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Other intangible assets, net

114,954

^[1]

67,647

63,553

Other assets

164,895

136,469

Total assets

1,589,872

1,474,045

Current liabilities

Accounts payable

50,341

41,261

Accrued expenses

319,189

275,023

Total Current Liabilities

77,840

82,727

447,370

399,011

Long-term debt

310,790

334,165

Other liabilities

127,116

76,799

Total liabilities

885,276

809,975

Commitments and contingencies (Notes 11 and 21)

Stockholders' equity

Class A common stock - 500 million shares authorized, $.001 par value, 90.6 million shares issued

Additional paid-in capital

466,349

439,635

Treasury stock, at cost - 38.0 million and 37.9 million shares

(1,304,694)

(1,250,123)

Accumulated other comprehensive loss

(66,318)

(84,122)

Retained earnings

1,609,168

1,558,589

Total stockholders' equity

704,596

664,070

Total liabilities and stockholders' equity

$ 1,589,872

$ 1,474,045

[1]	Goodwill was recast to reflect current period presentation by geographic region at December 31, 2016.

Consolidated Balance Sheets (Parenthetical) - $ / shares shares in Millions	Dec. 31, 2017	Dec. 31, 2016
Stockholders' equity:
Common stock, shares authorized (in shares)	500.0	500.0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares issued (in shares)	90.6	90.6
Treasury stock (in shares)	37.9	38.0

Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Consolidated Statements of Income [Abstract]
Revenue	$ 2,279,099	$ 2,207,797	$ 2,247,047
Cost of sales	502,078	500,457	489,510
Gross profit	1,777,021	1,707,340	1,757,537
Operating expenses:
Selling expenses	938,024	922,083	951,372
General and administrative expenses	564,514	554,153	561,463
Total operating expenses	1,502,538	1,476,236	1,512,835
Operating income	274,483	231,104	244,702
Other income (expense), net (Note 23)	(8,916)	(18,265)	(32,743)
Income before provision for income taxes	265,567	212,839	211,959
Provision for income taxes	136,130	69,753	78,913
Net income	$ 129,437	$ 143,086	$ 133,046
Net income per share:
Basic (in dollars per share)	$ 2.45	$ 2.58	$ 2.29
Diluted (in dollars per share)	$ 2.36	$ 2.55	$ 2.25
Weighted-average common shares outstanding:
Basic (in shares)	52,806	55,412	57,997
Diluted (in shares)	54,852	56,097	59,057

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Consolidated Statements of Comprehensive Income [Abstract]
Net income	$ 129,437	$ 143,086	$ 133,046
Other comprehensive income:
Foreign currency translation adjustment, net of taxes of $114, $2,483 and $(8,056), respectively	18,264	(13,127)	(18,967)
Net unrealized gains/(losses) on foreign currency cash flow hedges, net of taxes of $(325), $784 and $84, respectively	(152)	(1,423)	590
Less: Reclassification adjustment for realized losses/(gains) in current earnings, net of taxes of $756, $(935) and $169, respectively	(308)	1,697	(1,371)
Total other comprehensive income	17,804	(12,853)	(19,748)
Comprehensive income	$ 147,241	$ 130,233	$ 113,298

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other comprehensive income:
Foreign currency translation adjustment, tax	$ (8,056)	$ 2,483	$ 114
Net unrealized gains/(losses) on foreign currency cash flow hedges, tax	84	784	(325)
Reclassification adjustment for realized losses/(gains) in current earnings, tax	$ 169	$ (935)	$ 756

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock [Member] Class A [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Loss [Member]	Retained Earnings [Member]	Total
Balance at beginning of period at Dec. 31, 2014	$ 91	$ 414,394	$ (862,608)	$ (51,521)	$ 1,442,082	$ 942,438
Stockholders' Equity [Roll Forward]
Net income	0	0	0	0	133,046	133,046
Other comprehensive income, net of tax	0	0	0	(19,748)	0	(19,748)
Repurchase of Class A common stock (Note 12)	0	0	(164,094)	0	0	(164,094)
Exercise of employee stock options/vesting of stock awards	0	(6,324)	9,639	0	0	3,315
Excess tax benefit from equity awards	0	4,451	0	0	0	4,451
Stock-based compensation	0	7,400	0	0	0	7,400
Cash dividends	0	0	0	0	(81,187)	(81,187)
Balance at end of period at Dec. 31, 2015	91	419,921	(1,017,063)	(71,269)	1,493,941	825,621
Stockholders' Equity [Roll Forward]
Net income	0	0	0	0	143,086	143,086
Other comprehensive income, net of tax	0	0	0	(12,853)	0	(12,853)
Repurchase of Class A common stock (Note 12)	0	0	(247,208)	0	0	(247,208)
Exercise of employee stock options/vesting of stock awards	0	159	14,148	0	0	14,307
Excess tax benefit from equity awards	0	3,840	0	0	0	3,840
Stock-based compensation	0	8,890	0	0	0	8,890
Equity component of convertible note issuance (net)	0	6,825	0	0	0	6,825
Cash dividends	0	0	0	0	(78,438)	(78,438)
Balance at end of period at Dec. 31, 2016	91	439,635	(1,250,123)	(84,122)	1,558,589	664,070
Stockholders' Equity [Roll Forward]
Cumulative effect adjustment from adoption of ASU 2016-09 \| Accounting Standards Update 2016-09 [Member]	0	2,800	0	0	(2,800)	0
Net income	0	0	0	0	129,437	129,437
Other comprehensive income, net of tax	0	0	0	17,804	0	17,804
Repurchase of Class A common stock (Note 12)	0	0	(71,731)	0	0	(71,731)
Exercise of employee stock options/vesting of stock awards	0	9,479	14,964	0	0	24,443
Stock-based compensation	0	19,314	0	0	0	19,314
Acquisition of noncontrolling interests	0	(11,067)	0	0	0	(11,067)
Acquisition of equity method investment (0.2 million shares)	0	6,188	2,196	0	0	8,384
Cash dividends	0	0	0	0	(76,058)	(76,058)
Balance at end of period at Dec. 31, 2017	$ 91	$ 466,349	$ (1,304,694)	$ (66,318)	$ 1,609,168	$ 704,596

Consolidated Statements of Stockholder's Equity (Parenthetical) - shares shares in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Stockholders' Equity [Roll Forward]
Employee stock options (in shares)	1.2	1.1	0.7
Acquisition of equity method investment with treasury stock (in shares)	0.2

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net income	$ 129,437	$ 143,086	$ 133,046
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	71,564	72,397	71,365
Equity method earnings	(1,048)	0	0
Japan customs expense	0	31,355	0
Foreign currency (gains)/losses	(3,014)	8,863	27,235
Stock-based compensation	19,314	8,890	7,400
Deferred taxes	39,213	(17,652)	17,362
Changes in operating assets and liabilities:
Accounts receivable	(103)	3,357	(2,246)
Inventories, net	7,537	9,801	59,652
Prepaid expenses and other	14,250	37,789	13,572
Other assets	(11,658)	(3,969)	(15,752)
Accounts payable	6,834	13,443	(4,297)
Accrued expenses	22,490	(33,624)	15,902
Other liabilities	7,739	1,527	(1,130)
Net cash provided by operating activities	302,555	275,263	322,109
Cash flows from investing activities:
Purchases of property and equipment	(60,156)	(50,221)	(56,622)
Proceeds of investment sales	11,269	18,132	11,526
Purchases of investments	(11,332)	(17,080)	(15,750)
Acquisitions and investment in equity investee	(31,745)	(8,692)	0
Net cash used in investing activities	(91,964)	(57,861)	(60,846)
Cash flows from financing activities:
Payment of cash dividends	(76,058)	(78,438)	(81,187)
Repurchase of shares of common stock	(71,731)	(247,208)	(164,094)
Exercise of employee stock options and taxes paid related to the net shares settlement of stock awards	24,443	14,307	3,315
Income tax benefit of equity awards	0	5,651	5,337
Payments on long-term debt	(103,226)	(56,151)	(35,508)
Payment of debt issuance costs	0	(6,596)	0
Proceeds from long-term debt	67,000	233,721	36,217
Net cash used in financing activities	(159,572)	(134,714)	(235,920)
Effect of exchange rate changes on cash	18,134	(14,796)	(24,404)
Net increase in cash and cash equivalents	69,153	67,892	939
Cash and cash equivalents, beginning of period	357,246	289,354	288,415
Cash and cash equivalents, end of period	$ 426,399	$ 357,246	$ 289,354

The Company	12 Months Ended
The Company	Dec. 31, 2017
The Company [Abstract]
The Company	1. The Company Nu Skin Enterprises, Inc. (the "Company") is a leading, global direct selling company that develops and distributes premium-quality, innovative personal care products and nutritional supplements that are sold worldwide under the Nu Skin and Pharmanex brands and a small number of other products and services. Over the last several years, the Company has introduced new Pharmanex nutritional supplements and Nu Skin personal care products under its ageLOC anti-aging brand. The Company reports revenue from seven segments: Mainland China; South Korea; South Asia/Pacific, which consists of Australia, Brunei, French Polynesia, Indonesia, Malaysia, New Caledonia, New Zealand, the Philippines, Singapore, Thailand and Vietnam; Americas, which consists of the United States, Canada and Latin America; Japan; Hong Kong/Taiwan, which also includes Macau; and Europe, Middle East and Africa ("EMEA"), which consists of several markets in Europe as well as Israel, Russia, Ukraine and South Africa (the Company's subsidiaries operating in these markets in each segment are collectively referred to as the "Subsidiaries").

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2017

Summary of Significant Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Consolidation

The consolidated financial statements include the accounts of the Company and the Subsidiaries. All significant intercompany accounts and transactions are eliminated in consolidation.

Use of estimates

The preparation of these financial statements, in conformity with accounting principles generally accepted in the United States of America, required management to make estimates and assumptions that affected the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities, at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results may differ from these estimates.

Cash and cash equivalents

Cash equivalents are short-term, highly liquid instruments with original maturities of 90 days or less.

Inventories

Inventories consist primarily of merchandise purchased for resale and are stated at the lower of standard cost or net realizable value, using a standard cost method which approximates the first-in, first-out method. The Company had reserves of its inventory carrying value totaling $8.0 million and $8.1 million as of December 31, 2016 and 2017, respectively.

Inventories consist of the following (U.S. dollars in thousands):

	December 31,
	2016		2017

Raw materials	$	108,276	$	87,683
Finished goods		141,660		165,771
	$	249,936	$	253,454

Reserves of inventories consist of the following (U.S. dollars in thousands):

	2015			2016			2017

Beginning balance	$	56,034		$	20,744		$	7,995
Additions		38,605			24,906			16,382
Write-offs		(73,895	)		(37,655	)		(16,296	)
Ending balance	$	20,744		$	7,995		$	8,081

Property and equipment

Property and equipment are stated at cost less accumulated depreciation. Depreciation is recorded using the straight-line method over the following estimated useful lives:

	Buildings		39 years
	Furniture and fixtures		5 - 7 years
	Computers and equipment		3 -- 5 years
	Leasehold improvements		Shorter of estimated useful life or lease term
	Scanners		3 years
	Vehicles		3 - 5 years

Expenditures for maintenance and repairs are charged to expense as incurred. When an asset is sold or otherwise disposed of, the cost and associated accumulated depreciation are removed from the accounts and the resulting gain or loss is recognized in the statement of income. Property and equipment are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. An impairment loss is recognized if the carrying amount of the asset exceeds its fair value.

Goodwill and other intangible assets

Goodwill is recorded when the cost of acquired businesses exceeds the fair value of the identifiable net assets acquired. Goodwill and intangible assets with indefinite useful lives are not amortized, but are assessed for impairment annually on June 30. In addition, impairment testing is conducted when events occur or circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying amount. Goodwill and intangible assets with indefinite useful lives would be written down to fair value if considered impaired. Guidance under Accounting Standards Codification ("ASC") 350, Intangibles - Goodwill and Other, requires an entity to test goodwill for impairment on at least an annual basis. The Company had the option to perform a qualitative assessment to determine whether further impairment testing is necessary or to perform a quantitative assessment by comparing the fair value of a reporting unit to its carrying amount, including goodwill. Under the qualitative assessment, an entity is not required to calculate the fair value of a reporting unit unless the entity determines that it is more likely than not that its fair value is less than its carrying amount. If under the quantitative assessment the fair value of a reporting unit is less than its carrying amount, then the amount of the impairment loss, if any, must be measured. The Company used the quantitative assessment for all periods presented. Intangible assets with finite useful lives are amortized to their estimated residual values over such finite lives using the straight-line method and reviewed for impairment whenever events or circumstances warrant such a review.

No impairment charges were recorded for goodwill or intangibles during the periods presented.

Revenue recognition

Revenue is recognized when products are shipped, which is when title and risk of loss pass to the purchaser of the products. A reserve for product returns is accrued based on historical experience totaling $6.1 million and $4.5 million as of December 31, 2016 and 2017, respectively. During the years ended December 31, 2015, 2016 and 2017, the Company recorded sales returns of $65.6 million, $61.2 million and $53.8 million, respectively. The Company generally requires cash or credit card payment at the point of sale. Accounts receivable generally represents amounts due from credit card companies and are generally collected within a few days of the purchase. As such, the Company has determined that no allowance for doubtful accounts is necessary. Amounts received prior to shipment of products and title passage to the purchaser of the products are recorded as deferred revenue. The Company's sales compensation plans generally do not provide rebates or selling discounts for purchasing its products and services. The Company classifies selling discounts and rebates, if any, as a reduction of revenue at the time the sale is recorded.

Through the Company's product subscription and loyalty programs, which can vary from market to market, participants who commit to purchases on a monthly basis receive a discount from suggested retail or wholesale prices, as applicable. The Company applies this discount at the time of each purchase and not through a larger discount on the initial purchase. Participants may cancel their commitment at any time, however some markets charge a one-time early cancellation fee. All purchases under these programs are subject to the Company's standard product payment and return policies. In accordance with ASC 605-50, the Company classifies selling discounts and rebates, as a reduction of revenue at the time the sale is recorded.

Shipping and handling costs

Shipping and handling costs are recorded as cost of sales and are expensed as incurred.

Advertising expenses

Advertising costs are expensed as incurred. Advertising expense incurred for the years ended December 31, 2015, 2016 and 2017 totaled $11.0 million, $15.9 million and $15.6 million, respectively.

Selling expenses

Selling expenses are the Company's most significant expense and are classified as operating expenses. Selling expenses include distributor commissions as well as wages, benefits, bonuses and other labor and unemployment expenses the Company pays to its sales force in Mainland China. In each of the Company's markets, except Mainland China, Sales Leaders can earn "multi-level" compensation under the Company's global sales compensation plan, including commissions for product sales to their consumer groups as well as the product sales made through the sales network they have developed and trained. The Company does not pay commissions on sales materials.

Outside of Mainland China, the Company's distributors may make profits by purchasing the products from the Company at a discount and selling them to consumers with a mark-up. The Company does not account for nor pay additional commissions on these mark-ups received by distributors. In many markets, the Company also allows individuals who are not members of its sales force, referred to as "preferred customers," to buy products directly from the Company at a discount. The Company pays commissions on preferred customer purchases to the referring member of its sales force.

Research and development

Research and development costs are expensed as incurred and are included in general and administrative expenses in the accompanying consolidated statements of income and totaled $20.1 million, $24.3 million and $22.0 million in 2015, 2016 and 2017, respectively.

Deferred tax assets and liabilities

The Company accounts for income taxes in accordance with the Income Taxes Topic of the Financial Accounting Standards Codification. These standards establish financial accounting and reporting standards for the effects of income taxes that result from an enterprise's activities during the current and preceding years. The Company takes an asset and liability approach for financial accounting and reporting of income taxes. The Company pays income taxes in many foreign jurisdictions based on the profits realized in those jurisdictions, which can be significantly impacted by terms of intercompany transactions between the Company and its foreign affiliates. Deferred tax assets and liabilities are created in this process. The Company has netted these deferred tax assets and deferred tax liabilities by jurisdiction. Valuation allowances are established when necessary to reduce deferred tax assets to the amounts expected to be ultimately realized.

Uncertain tax positions

The Company files income tax returns in the U.S. federal jurisdiction, and in various state and foreign jurisdictions. The Company is no longer subject to tax examinations from the IRS for all years for which tax returns have been filed before 2011. With a few exceptions, the Company is no longer subject to state and local income tax examination by tax authorities for the years before 2011. In 2009, the Company entered into a voluntary program with the IRS called Compliance Assurance Process ("CAP"). The objective of CAP is to contemporaneously work with the IRS to achieve federal tax compliance and resolve all or most of the issues prior to filing of the tax return. The Company has elected to participate in the CAP program for 2018 and may elect to continue participating in CAP for future tax years; the Company may withdraw from the program at any time. In major foreign jurisdictions, the Company is generally no longer subject to income tax examinations for years before 2011. However, statutes in certain markets may be as long as ten years for transfer pricing related issues. Along with the IRS examination of 2011, the Company is currently under examination in certain foreign jurisdictions; however, the outcomes of those reviews are not yet determinable. In the first quarter of 2018, the Company received a preliminary tax assessment from Indonesia. The Company is currently evaluating the impact of the preliminary findings on its tax rate for the first quarter of 2018.

A reconciliation of the beginning and ending amount of unrecognized tax benefits included in other liabilities is as follows (U.S. dollars in thousands):

	2015			2016			2017

Gross balance at January 1	$	5,987		$	7,772		$	5,290
Increases related to prior year tax positions		1,677			185		─
Decreases related to prior year tax positions	─			─				(277	)
Increases related to current year tax positions		1,119			918			669
Settlements	─				(3,369	)		(159	)
Decreases due to lapse of statutes of limitations		(667	)		(252	)		(187	)
Currency adjustments		(344	)		36			178
Gross balance at December 31	$	7,772		$	5,290		$	5,514

At December 31, 2017, the Company had $5.5 million in unrecognized tax benefits of which $5.2 million, if recognized, would affect the effective tax rate. In comparison, at December 31, 2016, the Company had $5.3 million in unrecognized tax benefits of which $1.0 million, if recognized, would affect the effective tax rate. The Company's unrecognized tax benefits relate to multiple foreign and domestic jurisdictions. Due to potential increases in unrecognized tax benefits from the multiple jurisdictions in which the Company operates, as well as the expiration of various statutes of limitation, it is reasonably possible that the Company's gross unrecognized tax benefits, net of foreign currency adjustments, may increase within the next 12 months by a range of approximately $2.5 to $3.5 million.

During the years ended December 31, 2015, 2016 and 2017 the Company recognized $0.4 million, $(0.8) million and $0.7 million, respectively in interest and penalties expenses/(benefits). The Company had $1.7 million, $0.9 million and $1.6 million of accrued interest and penalties related to uncertain tax positions at December 31, 2015, 2016 and 2017, respectively. Interest and penalties related to uncertain tax positions are recognized as a component of income tax expense.

Net income per share

Net income per share is computed based on the weighted-average number of common shares outstanding during the periods presented. Additionally, diluted earnings per share data gives effect to all potentially dilutive common shares that were outstanding during the periods presented (Note 12).

Foreign currency translation

A significant portion of the Company's business operations occur outside of the United States. The local currency of each of the Company's Subsidiaries is considered its functional currency, except for the Company's subsidiaries in Singapore and Venezuela where the U.S. dollar is used. All assets and liabilities are translated into U.S. dollars at exchange rates existing at the balance sheet dates, revenue and expenses are translated at weighted-average exchange rates and stockholders' equity is recorded at historical exchange rates. The resulting foreign currency translation adjustments are recorded as a separate component of stockholders' equity in the consolidated balance sheets and transaction gains and losses are included in other income (expense) in the consolidated financial statements. Net of tax, the accumulated other comprehensive loss related to the foreign currency translation adjustments are $71.6 million (net of tax of $10.9 million), $84.7 million (net of tax of $13.4 million) and $66.4 million (net of tax of $5.8 million), at December 31, 2015, 2016 and 2017, respectively.

Classification of Venezuela as a Highly Inflationary Economy and Devaluation of Its Currency

Since 2010, Venezuela has been considered a highly inflationary economy. A market is considered to have a highly inflationary economy if it has a cumulative inflation rate of approximately 100% or more over a three-year period as well as other qualitative factors including historic inflation rate trends (increasing and decreasing), the capital intensiveness of the operation and other pertinent economic factors. The functional currency in highly inflationary economies is required to be the functional currency of the entity's parent company (which for the Company's Venezuela subsidiary is the U.S. dollar), and transactions denominated in the local currency are remeasured to the functional currency. The remeasurement of bolivars into U.S. dollars creates foreign currency transaction gains or losses, which the Company includes in its consolidated statement of income.

In the first quarter of 2015, a new foreign exchange mechanism ("SIMADI") was announced, which utilizes a variable exchange rate that was approximately 193 bolivars per U.S. dollar as of March 31, 2015. As a result of this new exchange mechanism, in 2015, the Company recorded charges totaling $10.2 million in other income (expense) to reflect additional foreign currency translation losses on its net monetary assets denominated in bolivars.

The current operating environment in Venezuela continues to be challenging, with high inflation in the country, government restrictions on foreign exchange and pricing controls, and the possibility of the government announcing further devaluations to its currency. Currency restrictions enacted by the Venezuelan government have impacted the ability of the Company to exchange foreign currency at the official rate to pay for imported products, license fees, commissions and other service fees. During the third quarter of 2016 the Company ceased business operations in Venezuela.

Fair value of financial instruments

The carrying value of financial instruments including cash and cash equivalents, accounts receivable and accounts payable approximate fair values due to the short-term nature of these instruments. The Company's current investments as of December 31, 2017 include certificates of deposits and pre-refunded municipal bonds that are classified by management as held-to-maturity as the Company had the positive intent and ability to hold to maturity. The carrying value of these current investments approximate fair values due to the short-term nature of these instruments. As of December 31, 2016 and 2017, the long-term debt fair value is $497.4 million and $515.2 million, respectively. The estimated fair value of the Company's debt is based on interest rates available for debt with similar terms and remaining maturities. The fair value of the Convertible Note is highly dependent upon the Company's stock price at the valuation date. The Company has classified these instruments as Level 2 in the fair value hierarchy. Fair value estimates are made at a specific point in time, based on relevant market information.

The FASB Codification defines fair value as the price that would be received to sell an asset or paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants at the measurement date. On a quarterly basis, the Company measures at fair value certain financial assets, including cash equivalents. Accounting standards specify a hierarchy of valuation techniques based on whether the inputs to those valuation techniques are observable or unobservable. Observable inputs reflect data obtained from independent sources, while unobservable inputs reflect the Company's market assumptions. These two types of inputs have created the following fair-value hierarchy:

•	Level 1 – quoted prices in active markets for identical assets or liabilities;

•	Level 2 – inputs, other than the quoted prices in active markets, that are observable either directly or indirectly;

•	Level 3 – unobservable inputs based on the Company's own assumptions.

Accounting standards permit companies, at their option, to measure many financial instruments and certain other items at fair value. The Company has elected not to apply the fair value option to existing eligible items.

Stock-based compensation

All share-based payments, including grants of stock options and restricted stock units, are required to be recognized in the Company's financial statements based upon their respective grant date fair values. The Black-Scholes option-pricing model is used to estimate the fair value of stock options. The determination of the fair value of stock options is affected by the Company's stock price and a number of assumptions, including expected volatility, expected life, risk-free interest rate and expected dividends. The Company uses historical volatility as the expected volatility assumption required in the Black-Scholes model. The expected life of the stock options is based on historical data trended into the future. The risk-free interest rate assumption is based on observed interest rates appropriate for the expected terms of the Company's stock options. The fair value of the Company's restricted stock units is based on the closing market price of its stock on the date of grant less the Company's expected dividend yield. The Company recognizes stock-based compensation net of any estimated forfeitures over the requisite service period of the award.

The total compensation expense related to equity compensation plans was $7.4 million, $8.9 million and $19.3 million for the years ended December 31, 2015, 2016 and 2017, respectively. In 2015, 2016 and 2017, these amounts reflect the reversal of $7.6 million, $9.6 million and none, respectively, for certain performance-based awards that were no longer expected to vest. For the years ended December 31, 2015, 2016 and 2017, all stock-based compensation expense was recorded within general and administrative expenses.

Reporting comprehensive income

Comprehensive income is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources, and it includes all changes in equity during a period except those resulting from investments by owners and distributions to owners.

Accounting for derivative instruments and hedging activities

The Company recognizes all derivatives as either assets or liabilities, with the instruments measured at fair value.

The Company's Subsidiaries enter into significant transactions with each other and third parties that may not be denominated in the respective Subsidiaries' functional currencies. The Company regularly monitors its foreign currency risks and seeks to reduce its exposure to fluctuations in foreign exchange rates using foreign currency exchange contracts and through certain intercompany loans of foreign currency.

Hedge effectiveness is assessed at inception and throughout the life of the hedge to ensure the hedge qualifies for hedge accounting treatment. Changes in fair value associated with hedge ineffectiveness, if any, are recorded in the results of operations currently. In the event that an anticipated transaction is no longer likely to occur, the Company recognizes the change in fair value of the derivative in its results of operations currently.

Changes in the fair value of derivatives are recorded in current earnings or accumulated other comprehensive loss, depending on the intended use of the derivative and its resulting designation. The gains and losses in accumulated other comprehensive loss stemming from these derivatives will be reclassified into earnings in the period during which the hedged forecasted transaction affects earnings. The fair value of the receivable and payable amounts related to these unrealized gains and losses is classified as other current assets and liabilities. The Company does not use such derivative financial instruments for trading or speculative purposes. Gains and losses on certain intercompany loans of foreign currency are recorded as other income (expense) in the consolidated statements of income.

Recent accounting pronouncements

In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). The new revenue recognition standard provides a five-step analysis of transactions to determine when and how revenue is recognized. The core principle is that a company should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The new standard will be effective for the Company in the first quarter of 2018. As a result of adopting this new accounting guidance, the Company will change the method of accounting for its loyalty points program from a cost provision method to a deferred revenue method. The Company is continuing to evaluate the impact this ASU, and related amendments and interpretive guidance, will have on its consolidated financial statements. The Company plans to adopt the new standard in the first quarter of 2018 using the modified retrospective transition method.

In July 2015, the FASB issued ASU 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory. This guidance requires an entity to measure inventory at the lower of cost and net realizable value, rather than at the lower of cost or market. This ASU was effective for the Company beginning on January 1, 2017. The adoption of this guidance did not have a significant impact on the Company's consolidated financial statements.

In February 2016, the FASB issued ASU 2016-02, Leases (Subtopic 842). ASU 2016-02 will require companies to recognize lease assets and lease liabilities on the balance sheet and disclose key information about leasing arrangements. For public companies, this standard is effective for annual reporting periods beginning after December 15, 2018, and early adoption is permitted. The Company is currently evaluating the impact of this standard on its consolidated financial position, results of operations, and cash flows.

In March 2016, the FASB issued ASU 2016-09, Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. The objective of this update was to simplify several aspects of the accounting for employee share-based payment transactions, including accounting for income taxes related to share-based compensation, the related classification in the statement of cash-flows, and accounting for share award forfeitures. This ASU was effective for the Company beginning on January 1, 2017. Prior to January 1, 2017, excess tax benefits were recognized in equity. As permitted, the Company elected to classify excess tax benefits as an operating activity in the Statement of Cash Flows instead of as a financing activity on a prospective basis and did not retroactively adjust prior periods. As also permitted by the new guidance, beginning January 1, 2017 the Company has elected to account for share award forfeitures as they occur. Previously, share-based compensation expense was recorded net of estimated forfeitures. A cumulative adjustment of $2.8 million was recorded to retained earnings and additional paid-in capital as of January 1, 2017. Prior periods were not retroactively adjusted.

In the second half of 2016, the FASB issued ASU Nos. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments, and 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. The objective of these updates is to reduce the diversity in practice in the classification of certain cash receipts and cash payments, and the presentation of restricted cash within an entity's statement of cash flows, respectively. These ASUs are effective for interim and annual fiscal periods beginning after December 15, 2017. Early adoption is permitted. The adoption of this guidance is not expected to have a material impact on the Company's consolidated financial statements.

In January 2017, the FASB issued ASU 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business. This guidance revises the definition of a business as it relates to acquisitions, disposals, goodwill impairments and consolidations. This ASU is effective for annual periods beginning after December 15, 2017. Early adoption is permitted. The adoption of this guidance is not expected to have a material impact on the Company's consolidated financial statements.

In January 2017, the FASB issued ASU 2017-04, Intangibles – Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment. This guidance simplifies the required test of goodwill for impairment by eliminating Step 2 from the goodwill impairment test. If a company determines in Step 1 of the goodwill impairment test that the carrying value of a reporting unit is less than the fair value, an impairment in that amount should be recorded to the income statement, rather than proceeding to Step 2. This ASU is effective for interim and annual impairment tests in fiscal years beginning after December 15, 2019. Early adoption is permitted. The adoption of this guidance is not expected to have a material impact on the Company's consolidated financial statements.

In December 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities. The new standard makes more financial and non-financial hedging strategies eligible for hedge accounting. It also amends the presentation and disclosure requirements and changes how companies assess effectiveness. For public companies, the amendments in this ASU are effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption is permitted in any interim period. The adoption of this guidance is not expected to have a material impact on the Company's consolidated financial statements.

Prepaid Expenses and Other

12 Months Ended

Dec. 31, 2017

Prepaid Expenses and Other [Abstract]

Prepaid Expenses and Other

3. Prepaid Expenses and Other

Prepaid expenses and other consist of the following (U.S. dollars in thousands):

	December 31,
	2016		2017

Deferred charges	$	9,319	$	4,256
Prepaid income taxes		6,799	─
Prepaid inventory and import costs		10,857		9,397
Prepaid rent, insurance and other occupancy costs		13,398		14,558
Prepaid promotion and event cost		4,126		3,581
Prepaid other taxes		4,778		5,559
Forward contracts		1,371		158
Deposits		1,079		1,147
Other		13,349		14,237
	$	65,076	$	52,893

Property and Equipment

12 Months Ended

Dec. 31, 2017

Property and Equipment

4. Property and Equipment

Property and equipment are comprised of the following (U.S. dollars in thousands):

	December 31,
	2016			2017

Land	$	33,158		$	33,667
Buildings		266,436			274,632
Construction in progress⁽¹⁾		31,124			53,125
Furniture and fixtures		82,194			95,378
Computers and equipment		143,014			156,994
Leasehold improvements		109,863			123,479
Scanners		10,578			11,212
Vehicles		2,090			2,339
		678,457			750,826
Less: accumulated depreciation		(233,725	)		(286,239	)
	$	444,732		$	464,587

⁽¹⁾

Construction in progress includes $25.8 million and $43.4 million as of December 31, 2016 and 2017, respectively, of eligible capitalized internal-use software development costs which will be reclassified to computers and equipment when placed into service.

Depreciation of property and equipment totaled $61.6 million, $60.8 million and $58.3 million for the years ended December 31, 2015, 2016 and 2017, respectively.

Goodwill

12 Months Ended

Dec. 31, 2017

Lease and Financing Obligations [Abstract]

5. Goodwill

During the first quarter of 2017, the Company realigned its operational segments and reporting structure to reflect how the business will be managed going forward. As part of this realignment, the Company divided its single operating segment into seven geographical reporting segments. The Company's reporting units for goodwill are its operating segments, which are also its reportable segments. As a result of the segment changes, the historical goodwill of $115.0 million was allocated to the seven reportable segments.

The following table presents goodwill allocated to the Company's reportable segments for the periods ended December 30, 2017 and December 31, 2016 (U.S. dollars in thousands):

	December 31, 2016⁽¹⁾		December 31, 2017

Mainland China	$	32,179	$	32,179
South Korea		29,261		29,261
Americas		9,449		9,449
South Asia/Pacific		18,537		18,537
Japan		16,019		16,019
Hong Kong/Taiwan		6,634		6,634
EMEA		2,875		2,875
Total	$	114,954	$	114,954

⁽¹⁾

Goodwill was recast to reflect current period presentation by geographic region at December 31, 2016.

Goodwill is not amortized, rather it is subject to annual impairment tests. Annual impairment tests were completed resulting in no impairment charges for any of the periods shown.

Other Intangible Assets

12 Months Ended

Dec. 31, 2017

Other Intangible Assets [Abstract]

Other Intangible Assets

6. Other Intangible Assets

Other intangible assets consist of the following (U.S. dollars in thousands):

	Carrying Amount at December 31,
Indefinite life intangible assets:	2016		2017

Trademarks and trade names	$	24,599	$	24,599
Other indefinite lived intangibles		3,763		3,763
	$	28,362	$	28,362

	December 31, 2016				December 31, 2017
Finite life intangible assets:	Gross Carrying Amount		Accumulated Amortization		Gross Carrying Amount		Accumulated Amortization		Weighted-average Amortization Period

Scanner technology	$	46,482	$	36,624	$	46,482	$	39,657	18 years
Developed technology		22,500		18,383		22,500		19,207	20 years
Distributor network		11,598		11,598		11,598		11,598	15 years
Trademarks		2,592		1,011		2,785		1,197	15 years
Other		46,219		26,584		57,550		29,971	8 years
	$	129,391	$	94,200	$	140,915	$	101,630	15 years

Amortization of finite-life intangible assets totaled $8.6 million, $8.4 million and $8.1 million for the years ended December 31, 2015, 2016 and 2017, respectively. In the year ended December 31, 2015, the Company wrote-off approximately $12.0 million of fully amortized intangible assets.

The estimated annual amortization expense for each of the five succeeding fiscal years are as follows (U.S. dollars in thousands):

Year Ending December 31,

	2018	$	8,978
	2019		8,876
	2020		4,898
	2021		4,148
	2022		5,201

Indefinite life intangible assets are not amortized, rather they are subject to annual impairment tests. Annual impairment tests were completed resulting in no impairment charges for any of the periods shown. Finite life intangibles are amortized over their useful lives unless circumstances occur that cause the Company to revise such lives or review such assets for impairment.

Other Assets

12 Months Ended

Dec. 31, 2017

Other Assets [Abstract]

Other Assets

7. Other Assets

Other assets consist of the following (U.S. dollars in thousands):

	December 31,
	2016		2017

Deferred taxes	$	35,752	$	33,785
Deposits for noncancelable operating leases		38,858		43,375
Cash surrender value for life insurance policies		32,286		37,737
Other		29,573		49,998
	$	136,469	$	164,895

Accrued Expenses

12 Months Ended

Dec. 31, 2017

Accrued Expenses [Abstract]

Accrued Expenses

8. Accrued Expenses

Accrued expenses consist of the following (U.S. dollars in thousands):

	December 31,
	2016		2017

Accrued sales force commissions and other payments	$	126,153	$	151,549
Accrued income taxes	─			13,075
Accrued other taxes		31,748		44,580
Accrued payroll and other employee expenses		25,412		38,167
Accrued payable to vendors		28,456		29,874
Accrued royalties		4,767		2,623
Sales return reserve		6,125		4,523
Deferred revenue		13,494		12,669
Other		38,868		22,129
	$	275,023	$	319,189

Other Liabilities

12 Months Ended

Dec. 31, 2017

Other Liabilities [Abstract]

Other Liabilities

9. Other Liabilities

Other liabilities consist of the following (U.S. dollars in thousands):

	December 31,
	2016		2017

Deferred tax liabilities	$	643	$	36,718
Reserve for other tax liabilities		6,264		7,163
Liability for deferred compensation plan		36,730		43,248
Pension plan benefits reserve		5,631		6,359
Build to suit – financing obligation		9,543		10,290
Deferred rent and deferred tenant incentives		5,952		6,389
Asset retirement obligation		5,682		6,578
Other		6,354		10,371
	$	76,799	$	127,116

Long-Term Debt

12 Months Ended

Dec. 31, 2017

Long-Term Debt [Abstract]

Long-Term Debt

10. Long-Term Debt

Credit Agreement

On October 9, 2014, the Company entered into a Credit Agreement (the "Credit Agreement") with various financial institutions, and Bank of America, N.A. as administrative agent. The Credit Agreement provides for a $127.5 million term loan facility, a 6.6 billion Japanese yen term loan facility and a $187.5 million revolving credit facility, each with a term of five years. On October 10, 2014, the Company drew the full amount of the term loan facilities, and as of December 31, 2016 and 2017, the Company had an outstanding balance of $47.5 million on the revolving credit facility. Any additional amounts drawn under the revolving credit facility will bear interest at rates that will be determined in accordance with the Credit Agreement. The Credit Agreement requires that the Company maintains a consolidated leverage ratio not exceeding 2.25 to 1.00 and a consolidated interest coverage ratio of no less than 3.00 to 1.00. The Company believes these covenants provide it with greater flexibility to pay dividends and repurchase stock. The Company is in compliance with its debt covenants.

Convertible Note

On June 16, 2016, the Company issued $210.0 million of convertible senior notes (the "Convertible Notes") in a private offering to a Chinese investor (the "Holder"). The Convertible Notes are senior unsecured obligations which will rank equal in right of payment to all senior unsecured indebtedness of the Company, and will rank senior in right of payment to any indebtedness that is contractually subordinated to the Convertible Notes. Interest on the Convertible Notes is payable semiannually in arrears on June 15 and December 15 of each year, beginning on December 15, 2016 at a rate of 4.75% per annum.

The Convertible Notes mature on June 15, 2020, unless repurchased or converted prior to maturity. Prior to the stated maturity date, the Company may, at its option, redeem all or part of the Convertible Notes at a price equal to 100% of the principal amount thereof, plus accrued and unpaid interest, if any, provided that its common stock share price is equal to or exceeds 180% of the applicable conversion price for 20 or more trading days (including the final three trading days) in the 30 consecutive trading days prior to the Company's exercise of such redemption right. The Holder of the Convertible Notes may, at its option, cause the Company to repurchase all of such Holder's Convertible Notes or any portion thereof that is equal to $1,000 in principal amount or multiples of $1,000 upon a change in control or a termination of trading of the Company's common stock, as those terms are defined in the indenture governing the Convertible Notes. In addition, each holder of the Convertible Notes shall have the right, at such holder's option, to convert all or any portion thereof that is equal to $1,000 in principal amount or multiples of $1,000 at any time beginning six calendar months following June 16, 2016, at the then-applicable conversion rate. Upon conversion by the Holder, the Convertible Notes will be settled in cash with respect to principal and any accrued and unpaid interest to such date and in the Company's common shares with respect to any additional amounts, based on the applicable conversion rate at such time. The Convertible Notes had an initial conversion rate of 21.5054 common shares per $1,000 principal amount of the Convertible Notes (which is equal to an initial conversion price of approximately $46.50 per common share). Throughout the term of the Convertible Notes, the conversion rate may be adjusted upon the occurrence of certain specified events.

Of the $210.0 million in proceeds received from the issuance of the Convertible Notes, $199.1 million was allocated to long-term debt (the "Liability Component") and $10.9 million was allocated to additional paid-in-capital (the "Equity Component") within the Company's consolidated balance sheet. The Liability Component was calculated by measuring the fair value of a similar debt instrument that does not have an associated conversion feature. The amount allocated to the Equity Component, which represents the conversion option, was calculated by deducting the fair value of the Liability Component from the par value of the Convertible Notes. The Company determined that the conversion option does not require separate accounting treatment as a derivative instrument because it is both indexed to the Company's own stock and would be classified in stockholders' equity if freestanding. The Equity Component will not be remeasured as long as it continues to meet the conditions for equity classification. The excess of the principal amount of the Liability Component over its carrying amount (the "Debt Discount") will be amortized to interest expense over the term of the Convertible Notes. As a result, the Liability Component will be accreted up to the Convertible Notes' $210.0 million face value, resulting in additional non-cash interest expense being recognized within the Company's consolidated statement of income. The effective interest rate on the Convertible Notes is approximately 7.1% per annum.

The net carrying amount of the Liability Component is as follows (U.S. dollars in thousands):

	December 31, 2017

Principal	$	210,000
Unamortized debt discount (conversion option)		(7,078	)
Total long-term debt, net		202,922
Unamortized debt discount (issuance costs)		(4,050	)
Net carrying amount	$	198,872

The net carrying amount of the Liability Component was recorded to long-term debt within the Company's consolidated balance sheet.

The Company incurred approximately $6.6 million of issuance costs related to the issuance of the Convertible Notes. Of the $6.6 million in issuance costs incurred, $6.3 million and $0.3 million were recorded to deferred financing cost and additional paid-in capital, respectively, in proportion to the allocation of the proceeds of the Convertible Notes. The $6.3 million recorded to deferred financing cost on the Company's consolidated balance sheet as a reduction of long-term debt is being amortized over the contractual term of the Convertible Notes using the effective interest method.

During the year ended December 31, 2017, the Company recognized $14.0 million in interest expense related to the Convertible Notes, which included $10.0 million of contractual interest and $4.0 million in amortization of debt issuance costs and in amortization of the Debt Discount.

The following table summarizes the Company's debt facilities as of December 31, 2016 and 2017:

Facility or Arrangement	Original Principal Amount	Balance as of December 31, 2016	Balance as of December 31, 2017⁽¹⁾⁽²⁾	Interest Rate	Repayment terms

Credit Agreement term loan facility:

U.S. dollar denominated:	$127.5 million	$108.4 million	$94.8 million	Variable 30 day: 4.319%	One half of the principal amount payable in increasing quarterly installments over a five-year period beginning on December 31, 2014, with the remainder payable at the end of the five-year term.

Japanese yen denominated:	6.6 billion yen	5.6 billion yen ($47.9 million as of December 31, 2016)	4.9 billion yen ($43.5 million as of December 31, 2017)	Variable 30 day: 2.75%	One half of the principal amount payable in increasing quarterly installments over a five-year period beginning on December 31, 2014, with the remainder payable at the end of the five-year term.

Credit Agreement revolving credit facility:

		$47.5 million	$47.5 million	Variable 30 day: 4.319%	Revolving line of credit expires October 2019.

South Korea subsidiary loan:	$20.0 million	$10.0 million	─	1.12%	Loan was paid off in March 2017.

Japan subsidiary loan:	2.0 billion yen	1.3 billion yen ($11.4 million as of December 31, 2016)	0.7 billion yen ($5.9 million as of December 31, 2017)	0.66%	Payable in semi-annual installments over three years that began on January 31, 2016.

Convertible note	$210.0 million	$210.0 million	$210.0 million	4.75%	Principal amount payable on June 15, 2020.

⁽¹⁾

As of December 31, 2017, the current portion of the Company's debt (i.e. becoming due in the next 12 months) included $16.7 million of the balance of its U.S. dollar denominated debt under the Credit Agreement facility, $7.7 million of the balance of its Japanese yen-denominated debt under the Credit Agreement facility and $5.9 million of the Japan subsidiary loan. The Company has classified the $47.5 million borrowed under the revolving line of credit as short term because it is the Company's intention to use the line of credit to borrow and pay back funds over short periods of time.

⁽²⁾

The carrying value of the debt reflects the amounts stated in the above table less a debt discount of $9.1 million and debt issuance costs of $4.0 million (consisting of $11.1 million related to the Convertible Note and $2.0 million related to the credit agreement), which is not reflected in this table.

Interest expense relating to debt totaled $7.9 million, $15.6 million and $22.2 million for the years ended December 31, 2015, 2016 and 2017, respectively.

Maturities of all long-term debt at December 31, 2017, based on the year-end exchange rate, are as follows (U.S. dollars in thousands):

Year Ending December 31,

2018	$	77,840
2019		113,928
2020		210,000
2021	─
2022	─
Thereafter	─
Total⁽¹⁾	$	401,768

⁽¹⁾	The carrying value of the debt reflects the amounts stated in the above table less a debt discount of $13.1 million, which is not reflected in this table.

Lease and Financing Obligations

12 Months Ended

Dec. 31, 2017

Lease and Financing Obligations

11. Lease and Financing Obligations

In 2014, the Company's subsidiary in South Korea entered into a lease agreement (the "Lease") with a third-party landlord for a new regional headquarters. As part of the Lease, the landlord agreed to renovate an existing building (the "Existing Building") and construct a new building (the "New Building") adjacent to the Existing Building. The Lease provided that when such renovations and construction were completed, the Company and the landlord would enter into a new lease agreement (the "New Lease") for the Existing Building and the New Building. In April 2015, the Company and the landlord entered into the New Lease on terms generally consistent with the 2014 lease. The New Lease term is for the period May 1, 2015 through April 30, 2025, with an option to extend the agreement for 10 years.

The Company accounts for its lease of the Existing Building as an operating lease. As an inducement to enter into the Lease, the landlord agreed to make certain improvements on behalf of the Company to the Existing Building. The improvements have been accounted for by the Company as a tenant incentive.

The Company has concluded that it is the deemed owner (for accounting purposes only) of the New Building during the construction period under build-to-suit lease accounting. Construction of the New Building began in June 2014 and was completed in June 2015. During the construction period, the Company recorded estimated project construction costs as a construction in progress asset in "Property and equipment, net" and a corresponding long-term liability in "Other liabilities," respectively, in its consolidated balance sheets. In addition, the amounts that the Company has paid or incurred for normal tenant improvements were also recorded to the construction-in-progress asset.

At the end of the construction period in June 2015, the Company concluded that the New Lease of the New Building did not meet "sale-leaseback" criteria; therefore, the asset and obligation recognized during construction will remain recorded in the Company's consolidated balance sheets. As of December 31, 2015, the completed building and normal tenant improvements under the lease have been reclassified from construction in progress to buildings and leasehold improvements, respectively. The Company accounts for the New Lease of the New Building as a financing with the associated lease payments allocated between the New Building and the underlying parcel of land on a relative fair value basis. Rent expense attributed to the underlying parcel of land, and representing the imputed cost to lease the land, is accounted for on a straight-line basis as the land element is an operating lease.

Lease payments attributed to the New Building are allocated between principal and interest expense using the effective interest method. The principal portion of the lease payment attributed to the New Building is reflected as a principal reduction of the financing obligation. In addition, the asset, which represents the total estimated cost of construction of the New Building at the end of the construction period, is being depreciated over the initial ten-year term of the New Lease to its expected residual value. At the conclusion of the New Lease, the Company will de-recognize both the net book value of the asset and the unamortized portion of the financing obligation. The amount of asset depreciation and financing obligation amortization is structured at the outset such that the remaining residual book value of the asset is equal to the remaining financing obligation at the end of the lease term.

As of December 31, 2016, the Company had recognized $18.9 million as the value of the New Building offset by accumulated depreciation of $0.8 million and a financing obligation of $10.0 million, net of a $9.1 million deposit paid directly to the landlord, as part of other liabilities in its consolidated balance sheet. As of December 31, 2017, the Company had recognized $20.8 million as the value of the New Building offset by accumulated depreciation of $1.5 million and a financing obligation of $10.8 million, net of a $10.3 million deposit paid directly to the landlord, as part of other liabilities in its consolidated balance sheet.

As of December 31, 2016, the tenant incentive asset and deferred tenant incentive liability associated with the Existing Building totaled $4.9 million and $4.5 million, respectively. As of December 31, 2017, the tenant incentive asset and deferred tenant incentive liability associated with the Existing Building totaled $4.9 million and $4.5 million, respectively.

In addition to the lease arrangements described above, the Company leases office space and computer hardware under noncancelable long-term operating leases. Most leases include renewal options of at least three years.

Minimum future operating leases and financing obligations at December 31, 2017 are as follows (U.S. dollars in thousands):

Year Ending December 31,	Operating Leases		Financing Obligations

2018	$	41,788	$	736
2019		27,088		758
2020		14,907		781
2021		10,036		790
2022		7,672		804
Thereafter		13,250		2,027
Total minimum lease payments	$	114,741	$	5,896

Rent expense for operating leases totaled $52.4 million, $48.2 million and $50.7 million for the years ended December 31, 2015, 2016 and 2017, respectively. Interest expense associated with the financing obligations was $0.1 million, $0.2 million and $0.2 million for the years ended December 31, 2015, 2016 and 2017, respectively.

Capital Stock

12 Months Ended

Dec. 31, 2017

Capital Stock [Abstract]

Capital Stock

12. Capital Stock

The Company's authorized capital stock consists of 25 million shares of preferred stock, par value $.001 per share, 500 million shares of Class A common stock, par value $.001 per share, and 100 million shares of Class B common stock, par value $.001 per share. The shares of Class A common stock and Class B common stock are identical in all respects, except for voting rights and certain conversion rights and transfer restrictions, as follows: (1) each share of Class A common stock entitles the holder to one vote on matters submitted to a vote of the Company's stockholders and each share of Class B common stock entitles the holder to ten votes on each such matter; (2) stock dividends of Class A common stock may be paid only to holders of Class A common stock and stock dividends of Class B common stock may be paid only to holders of Class B common stock; (3) if a holder of Class B common stock transfers such shares to a person other than a permitted transferee, as defined in the Company's Certificate of Incorporation, such shares will be converted automatically into shares of Class A common stock; and (4) Class A common stock has no conversion rights; however, each share of Class B common stock is convertible into one share of Class A common stock, in whole or in part, at any time at the option of the holder. All outstanding Class B shares have been converted to Class A shares. As of December 31, 2016 and 2017, there were no preferred or Class B common shares outstanding.

Weighted-average common shares outstanding

The following is a reconciliation of the weighted-average common shares outstanding for purposes of computing basic and diluted net income per share (in thousands):

	Year Ended December 31,
	2015		2016		2017

Basic weighted-average common shares outstanding		57,997		55,412		52,806
Effect of dilutive securities: Stock awards and options		1,060		683		1,110
Convertible note		—		2		936
Diluted weighted-average common shares outstanding		59,057		56,097		54,852

For the years ended December 31, 2015, 2016 and 2017, other stock options totaling 1.8 million, 2.0 million and 0.4 million, respectively, were excluded from the calculation of diluted earnings per share because they were anti-dilutive. The convertible note has a dilutive impact on EPS when the average market price of the Company's common stock for a given period exceeds the initial conversion price. See Note 10 for discussion of initial conversion price and conversion rate.

Repurchases of common stock

In 1998, the Company's board of directors approved a stock repurchase plan authorizing the Company to repurchase $10.0 million of its outstanding shares of Class A common stock on the open market or in private transactions. The Company's board from time to time increased the amount authorized under the 1998 stock repurchase plan, including an increase of $400.0 million announced in August 2013. In October 2015, the Company's board terminated the 1998 stock repurchase plan and approved a new repurchase plan with an initial authorization amount of $500.0 million. The repurchases are used primarily for strategic initiatives and to offset dilution from the Company's equity incentive plans and from conversion of the Convertible Notes. During the years ended December 31, 2015, 2016 and 2017, the Company repurchased 3.8 million, 4.5 million and 1.2 million shares of Class A common stock for an aggregate price of $164.1 million, $247.2 million and $71.7 million, respectively. At December 31, 2017, $128.0 million was available for repurchases under the 2015 stock repurchase plan.

Stock-Based Compensation

12 Months Ended

Dec. 31, 2017

Stock-Based Compensation [Abstract]

Stock-Based Compensation

13. Stock–Based Compensation

At December 31, 2017, the Company had the following stock-based employee compensation plans:

Equity Incentive Plans

In April 2010, the Company's Board of Directors approved the Nu Skin Enterprises, Inc. 2010 Omnibus Incentive Plan (the "2010 Omnibus Incentive Plan"). This plan was approved by the Company's stockholders at the Company's 2010 Annual Meeting of Stockholders held in May 2010. The 2010 Omnibus Incentive Plan provides for granting of a variety of equity-based awards including stock options, stock appreciation rights, restricted stock, restricted stock units, other share-based awards, performance cash, performance shares and performance units to executives, other employees, independent consultants and directors of the Company and its subsidiaries. Options granted under the 2010 Omnibus Incentive Plan are generally non-qualified stock options, but the 2010 Omnibus Incentive Plan permits some stock options granted to qualify as "incentive stock options" under the U.S. Internal Revenue Code. The exercise price of a stock option generally is equal to the fair market value of the Company's common stock on the stock option grant date. The contractual term of a stock option granted under the 2010 Omnibus Incentive Plan is seven years. Currently, all shares issued upon the exercise of stock options are from the Company's treasury shares. Subject to certain adjustments, 7.0 million shares were authorized for issuance under the 2010 Omnibus Incentive Plan. On June 3, 2013, the Company's stockholders approved an Amended and Restated 2010 Omnibus Incentive Plan, which among other things increased the number of shares available for awards by 3.2 million shares. On May 24, 2016, the Company's stockholders approved a Second Amended and Restated 2010 Omnibus Incentive Plan, which among other things increased the number of shares available for awards by 3.8 million shares.

In July 2013, the compensation committee of the board of directors approved the grant of performance stock options to certain key employees under the Amended and Restated 2010 Omnibus Incentive Plan. Vesting for the options is performance based, with the options vesting in four installments if the Company's earnings per share equal or exceed the four established performance levels, measured in terms of diluted earnings per share. One fourth of the options will vest upon earnings per share meeting or exceeding the first performance level, one fourth of the options will vest upon earnings per share meeting or exceeding the second performance level, one fourth of the options will vest upon earnings per share meeting or exceeding the third performance level and one fourth of the options will vest upon earnings per share meeting or exceeding the fourth performance level. The unvested options will terminate upon the Company's failure to meet certain performance thresholds for each of years 2013 through 2019. In addition, all unvested options will terminate on March 30, 2020. The Company has also issued other performance-based awards to a limited number of participants that similarly vest, or become eligible for vesting, upon achievement of various performance targets.

The fair value of stock option awards was estimated using the Black-Scholes option-pricing model with the following assumptions and weighted-average fair values as follows:

	December 31,
Stock Options:	2015		2016		2017

Weighted-average grant date fair value of grants	$	16.26	$	12.59	$	18.84
Risk-free interest rate⁽¹⁾		1.7%		1.4%		2.1%
Dividend yield⁽²⁾		2.1%		2.3%		2.5%
Expected volatility⁽³⁾		46.8%		47.9%		48.2%
Expected life in months⁽⁴⁾	65 months		68 months		68 months

⁽¹⁾

The risk-free interest rate is based upon the rate on a zero-coupon U.S. Treasury bill, for periods within the contractual life of the option, in effect at the time of the grant.

⁽²⁾

The dividend yield is based on the average of historical stock prices and actual dividends paid.

⁽³⁾

Expected volatility is based on the historical volatility of the Company's stock price, over a period similar to the expected life of the option.

⁽⁴⁾

The expected term of the option is based on the historical employee exercise behavior, the vesting terms of the respective option, and a contractual life of either seven or ten years.

Options under the plans as of December 31, 2017 and changes during the year ended December 31, 2017 were as follows:

	Shares (in thousands)			Weighted-average Exercise Price		Weighted- average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in thousands)

Options activity – service based
Outstanding at December 31, 2016		2,207.0		$	39.93
Granted	─			─
Exercised		(324.4	)		34.71
Forfeited/cancelled/expired		(489.7	)		43.85
Outstanding at December 31, 2017		1,392.9			39.76		4.36	$	41,756
Exercisable at December 31, 2017		725.5			43.14		3.55		20,237

Options activity – performance based
Outstanding at December 31, 2016		3,725.9		$	58.23
Granted		298.0			50.93
Exercised		(853.0	)		30.86
Forfeited/cancelled/expired		(869.4	)		70.17
Outstanding at December 31, 2017		2,301.5			62.89		3.61	$	26,206
Exercisable at December 31, 2017		294.1			35.58		4.17		9,601

Options activity – all options
Outstanding at December 31, 2016		5,932.9		$	51.42
Granted		298.0			50.93
Exercised		(1,177.4	)		31.92
Forfeited/cancelled/expired		(1,359.1	)		60.69
Outstanding at December 31, 2017		3,694.4			54.17		3.90	$	67,962
Exercisable at December 31, 2017		1,019.6			40.96		3.73		29,838

The aggregate intrinsic value in the table above represents the total pretax intrinsic value (the difference between the Company's closing stock price on the last trading day of the respective years and the exercise price, multiplied by the number of in-the-money options) that would have been received by the option holders had all option holders exercised their options on December 31, 2017. This amount varies based on the fair market value of the Company's stock.

Cash proceeds, tax benefits and intrinsic value related to total stock options exercised during 2015, 2016 and 2017, were as follows (U.S. dollars in thousands):

	December 31,
	2015		2016		2017

Cash proceeds from stock options exercised	$	13,041	$	15,707	$	26,980
Tax benefit realized for stock options exercised		4,451		3,840		6,457
Intrinsic value of stock options exercised		12,085		30,587		42,749

Nonvested restricted stock awards as of December 31, 2017 and changes during the year ended December 31, 2017 were as follows:

	Number of Shares (in thousands)			Weighted-average Grant Date Fair Value

Nonvested at December 31, 2016		596.4		$	53.62

Granted		261.6			50.95
Vested		(203.2	)		53.94
Forfeited		(91.9	)		60.30

Nonvested at December 31, 2017		562.9			51.17

Stock-based compensation expense is recognized on a straight-line basis, except for performance-based awards for which expense is recognized using a graded-attribution method if the results are materially different than the straight-line method. The Company recognized $2.6 million, $5.8 million and $4.0 million of expense related to service condition stock options in 2015, 2016 and 2017, respectively; and $10.9 million, $10.5 million and $11.3 million of expense related to service condition restricted stock units in 2015, 2016 and 2017, respectively. For performance stock options and performance stock units, an expense is recorded each period for the estimated expense associated with the projected achievement of the performance-based targets. The Company recognized $6.5 million of income, $7.1 million of income and $3.9 million of expense related to performance stock options in 2015, 2016 and 2017, respectively; and $0.4 million of expense, $0.3 million of income and $0.1 million of expense related to performance stock units in 2015, 2016 and 2017, respectively. The amounts in 2015 and 2016 reflect the reversal of stock compensation for awards no longer expected to vest.

As of December 31, 2017, there was $6.4 million of unrecognized stock-based compensation expense related to nonvested stock option awards. That cost is expected to be recognized over a weighted-average period of 1.9 years. As of December 31, 2017, there was $16.3 million of unrecognized stock-based compensation expense related to nonvested restricted stock awards. That cost is expected to be recognized over a weighted-average period of 2.4 years.

Fair Value

12 Months Ended

Dec. 31, 2017

Fair Value [Abstract]

Fair Value

14. Fair Value

The following tables present the fair value hierarchy for those assets and liabilities measured at fair value on a recurring basis (U.S. dollars in thousands):

	Fair Value at December 31, 2016
	Level 1		Level 2		Level 3		Total

Financial assets (liabilities):
Cash equivalents and current investments	$	50,307	$	─	$	─	$	50,307
Other long-term assets		2,782	─		─			2,782
Forward contracts	─			1,371	─			1,371
Life insurance contracts	─		─			32,286		32,286
Total	$	53,089	$	1,371	$	32,286	$	86,746

	Fair Value at December 31, 2017
	Level 1		Level 2		Level 3		Total

Financial assets (liabilities):
Cash equivalents and current investments	$	36,531	$	─	$	─	$	36,531
Other long-term assets		3,726	─		─			3,726
Forward contracts	─			158	─			158
Life insurance contracts	─		─			37,737		37,737
Total	$	40,257	$	158	$	37,737	$	78,152

The following methods and assumptions were used to determine the fair value of each class of assets and liabilities recorded at fair value in the consolidated balance sheets:

Cash equivalents and current investments: Cash equivalents and current investments primarily consist of highly rated money market funds with maturities of three months or less, and are purchased daily at par value with specified yield rates. Due to the high ratings and short-term nature of the funds, the Company considers all cash equivalents and current investments as Level 1. Current investments include $10.9 million and $11.8 million as of December 31, 2016 and 2017, respectively, that is restricted for the Company's voluntary participation in a consumer protection cooperative in South Korea.

Forward contracts: To hedge foreign currency risks, the Company uses foreign currency exchange forward contracts, where possible and practical. These forward contracts are valued using standard valuation formulas with assumptions about foreign currency exchange rates derived from existing exchange rates as discussed in Note 18, "Derivative Financial Instruments".

Life insurance contracts: ASC 820 preserves practicability exceptions to fair value measurements provided by other applicable GAAP. The guidance in ASC 715-30-35-60 allows a reporting entity, as a practical expedient, to use cash surrender value or conversion value as an expedient for fair value when it is present. Accordingly, the Company determines the fair value of its life insurance contracts as the cash-surrender value of life insurance policies held in its Rabbi Trust as disclosed in Note 17, "Executive Deferred Compensation Plan".

The following table provides a summary of changes in fair value of the Company's Level 3 marketable securities (U.S. dollars in thousands):

Life Insurance Contracts	2016			2017

Beginning balance at January 1	$	27,292		$	32,287
Actual return on plan assets:
Relating to assets still held at the reporting date		2,196			4,917
Purchases and issuances		3,051			895
Sales and settlements		(252	)		(362	)
Transfers into Level 3	─			─
Ending balance at December 31	$	32,287		$	37,737

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Income Taxes

12 Months Ended

Dec. 31, 2017

Income Taxes [Abstract]

Income Taxes

15. Income Taxes

On December 22, 2017, tax reform legislation known as the Tax Cuts and Jobs Act (the Tax Reform Act) was enacted in the United States (U.S.). The Tax Reform Act significantly revises the U.S. corporate income tax by, among other things, lowering the corporate income tax rate to 21%, implementing a modified territorial tax system and imposing a one-time repatriation tax on deemed repatriated earnings and profits of U.S.-owned foreign subsidiaries (the Toll Charge).

Pursuant to the Securities and Exchange Commission Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act (SAB 118), given the amount and complexity of the changes in tax law resulting from the Tax Reform Act, the Company has not finalized the accounting for the income tax effects of the Tax Reform Act. This includes the provisional amounts recorded related to the Toll Charge, the recording of a valuation allowance relating to foreign tax credits, the write-off and remeasurement of deferred tax assets and deferred tax liabilities and the change in the Company's indefinite reinvestment assertion. Further, the Company is in the process of analyzing the effects of new taxes due on certain foreign income, such as GILTI (global intangible low-taxed income), BEAT (base-erosion anti-abuse tax), FDII (foreign-derived intangible income), limitations on the deductibility of executive compensation, limitations on interest expense deductions (if certain conditions apply), and other provisions of the Tax Reform Act that are effective starting in 2018. Because of the complexity of the new GILTI tax rules, we are continuing to evaluate this provision of the Tax Act and the application of ASC 740. Under U.S. GAAP, we are allowed to make an accounting policy choice of either (1) treating taxes due on future U.S. inclusions in taxable income related to GILTI as a current-period expense when incurred (the "period cost method") or (2) factoring such amounts into a company's measurement of its deferred taxes (the "deferred method"). Our selection of an accounting policy with respect to the new GILTI tax rules will depend, in part, on analyzing our global income to determine whether we expect to have future U.S. inclusions in taxable income related to GILTI and, if so, what the impact is expected to be. We are not yet able to reasonably estimate the effect of this provision of the Tax Act. Therefore, we have not made any adjustments related to potential GILTI tax in our financial statements and have not made a policy decision regarding whether to record deferred taxes on GILTI.

The Company has preliminarily accounted for the effects of the Tax Reform Act, which resulted in a charge of $47.7 million to deferred income tax expense in the fourth quarter 2017, comprised of a $52.0 million charge from recognition of a valuation allowance on foreign tax credit carryforwards, $7.3 million charge related to reversal of indefinite reinvestment, $4.1 million charge related to the reduction in FIN 48 assets, a benefit of $7.7 million due to the write-off of net outside basis deferred tax liabilities, a benefit of $3.1 million related to the tax effect on OCI and a benefit of $4.9 million from the estimated impact of remeasurement of U.S. deferred tax assets and liabilities at a lower enacted corporate income tax rate.

The Toll Charge is based on the Company's post-1986 earnings and profits (E&P) of U.S.-owned foreign subsidiaries for which the Company had previously deferred U.S. income taxes. The total estimated Toll Charge of $96 million is estimated to be offset entirely by foreign tax credits. The Company currently estimates that no additional cash taxes will be paid as a result of the Toll Charge. Due to the modified territorial system that has been implemented in the U.S. the company wrote-off the net outside basis deferred tax liabilities balances after analyzing the impacts of the Toll Charge resulting in a tax benefit of $7.7 million.

As of December 22, 2017, the company no longer considers undistributed earnings and profits of U.S. owned subsidiaries to be indefinitely reinvested and recorded a tax expense of $7.3 million related to foreign withholding taxes on unremitted foreign earnings that were previously asserted to be indefinitely reinvested in the fourth quarter of 2017.

The impact of the Tax Reform Act may differ from this estimate, possibly materially, during the one-year measurement period due to, among other things, further refinement of the Company's calculations, changes in interpretations and assumptions the Company has made, guidance that may be issued and actions the Company may take as a result of the Tax Reform Act.

Consolidated income before provision for income taxes consists of the following for the years ended December 31, 2015, 2016 and 2017 (U.S. dollars in thousands):

	2015		2016			2017

U.S.	$	134,473	$	(19,119	)	$	1,135
Foreign		77,486		231,958			264,432
Total	$	211,959	$	212,839		$	265,567

The provision for current and deferred taxes for the years ended December 31, 2015, 2016 and 2017 consists of the following (U.S. dollars in thousands):

	2015			2016			2017
Current
Federal	$	6,328		$	─		$	(14,358	)
State		1,483			(718	)		1,814
Foreign		50,403			70,652			104,688
		58,214			69,934			92,144
Deferred
Federal		16,556			(27,171	)		45,593
State		(674	)		1,104			(2,273	)
Foreign		4,817			25,886			666
		20,699			(181	)		43,986
Provision for income taxes	$	78,913		$	69,753		$	136,130

The principal components of deferred taxes are as follows (U.S. dollars in thousands):

	Year Ended December 31,
	2016			2017
Deferred tax assets:
Inventory differences	$	2,521		$	2,861
Foreign tax credit and other foreign benefits		145,169			52,408
Stock-based compensation		11,470			6,327
Accrued expenses not deductible until paid		32,796			39,326
Foreign currency exchange		4,826			2,001
Net operating losses		9,584			5,230
Capitalized research and development		358			197
Other		1,063			211
Gross deferred tax assets		207,787			108,561
Deferred tax liabilities:
Foreign currency exchange		105			874
Foreign withholding taxes	─				29,018
Intangibles step-up		12,107			6,568
Overhead allocation to inventory		4,820			3,977
Amortization of intangibles		19,091			11,475
Foreign outside basis in controlled foreign corporation		106,846		─
Other		20,572			2,676
Gross deferred tax liabilities		163,541			54,588
Valuation allowance		(9,137	)		(56,906	)
Deferred taxes, net	$	35,109		$	(2,933	)

At December 31, 2017, the Company had foreign operating loss carryforwards of $17.1 million for tax purposes, which will be available to offset future taxable income. If not used, $5.7 million of carryforwards will expire between 2018 and 2027, while $11.4 million do not expire. A valuation allowance has been placed on foreign operating loss carryforwards of $15.9 million. In addition, a valuation allowance has been recorded on the foreign tax credit carryforward of $52.0 million which will expire between 2026 and 2027. The Company uses the tax law ordering approach when determining when excess tax benefits have been realized.

The valuation allowance for the foreign tax credit carryforwards was recorded as a result of the Tax Reform Act. A valuation allowance has also been recognized for foreign operating loss carryforwards and unrealized foreign exchange losses. The valuation allowances were recognized for assets which it is more likely than not some portion or all of the deferred tax asset will not be realized. In making such determination, the Company considers all available positive and negative evidence, including future reversals of existing taxable temporary difference, projected future taxable income, tax planning strategies and recent financial operations. When the Company determines that there is sufficient positive evidence to utilize the foreign tax credits or the net operating losses, the valuation will be released which would reduce the provision for income taxes.

The deferred tax asset valuation adjustments for the years ended December 31, 2015, 2016 and 2017 are as follows (U.S. dollars in thousands):

	Year Ended December 31,
	2015			2016			2017

Balance at the beginning of period	$	35,999		$	49,271		$	9,137
Additions charged to cost and expenses		12,948			692			53,983	⁽⁵⁾
Decreases		(2,943	)⁽¹⁾		(40,442	)⁽⁴⁾		(6,400	)⁽⁶⁾
Adjustments		3,267	⁽²⁾		(384	)⁽²⁾		186	⁽²⁾
Balance at the end of the period	$	49,271	⁽³⁾	$	9,137		$	56,906

⁽¹⁾

Decreases in valuation allowance due to lapse in statute of limitation of the net operating losses carryforward which had no impact to the income statement.

⁽²⁾

Represents the net currency effects of translating valuation allowances at current rates of exchange.

⁽³⁾

The increase was due primarily to the deferred tax assets created by the unrealized loss in Venezuela for which the Company set up a full valuation allowance.

⁽⁴⁾

Decrease in valuation allowance due to lapse in statute of limitation of the net operating losses carryforward and due to the write off of Venezuelan deferred tax assets, which had no impact to the income statement.

⁽⁵⁾

Increase in valuation is due primarily to the $52.0 million that was recorded on the foreign tax credit carryforward. The additional amount is due to net operating losses in foreign markets.

⁽⁶⁾

Decrease is due primarily to the write-off of Brazil deferred tax assets, which had no impact to the income statement, as a valuation allowance had been previously recorded against the asset.

The components of deferred taxes, net on a jurisdiction basis are as follows (U.S. dollars in thousands):

	Year Ended December 31,
	2016		2017

Net noncurrent deferred tax assets	$	35,752	$	33,785

Net noncurrent deferred tax liabilities		643		36,718

Deferred taxes, net	$	35,109	$	(2,933	)

The Company is subject to regular audits by federal, state and foreign tax authorities. These audits may result in proposed assessments that may result in additional tax liabilities.

The actual tax rate for the years ended December 31, 2015, 2016 and 2017 compared to the statutory U.S. Federal tax rate is as follows:

	Year Ended December 31,
	2015			2016			2017

Income taxes at statutory rate		35.00	%		35.00	%		35.00	%
Indefinite reinvestment		.92			(1.98	)		2.75
Excess tax benefit from equity award	─			─				(2.38	)
Non-deductible expenses		0.09			0.11			0.17
Controlled foreign corporation losses		1.09			(2.63	)		(0.13	)
Valuation allowance recognized foreign tax credit	─			─				19.59
Write-off outside basis DTL	─			─				(2.89	)
Revaluation of deferred taxes	─			─				(1.28	)
Section 987 implementation	─				2.69		─
Other		0.13			(0.42	)		0.43
		37.23	%		32.77	%		51.26	%

The effective tax rate for 2017 was impacted largely due to the Tax Reform Act.

Employee Benefit Plan	12 Months Ended
Employee Benefit Plan	Dec. 31, 2017
Employee Benefit Plan [Abstract]
Employee Benefit Plan	16. Employee Benefit Plan The Company has a 401(k) defined-contribution plan which permits participating employees to defer up to a maximum of 100% of their compensation, subject to limitations established by the Internal Revenue Service. Employees age 18 and older are eligible to contribute to the plan starting the first day of employment. After completing at least one day of service, employees are eligible to receive matching contributions from the Company. In 2015, 2016, and 2017 the Company matched employees' base pay up to 4% each year. The Company's matching contributions cliff vest after two years of service. The Company recorded compensation expense of $2.8 million, $2.8 million and $3.2 million for the years ended December 31, 2015, 2016 and 2017, respectively, related to its contributions to the plan. The Company may make additional discretionary contributions to the plan of up to 10% of employees' base pay. The Company's discretionary contributions vest 20% per year for an employee's first five years of service. For the years ended December 31, 2015, 2016 and 2017 the Company did not make any additional discretionary contributions. The Company has a defined benefit pension plan for its employees in Japan. All employees of Nu Skin Japan, after certain years of service, are entitled to pension plan benefits when they terminate employment with Nu Skin Japan. The accrued pension liability was $4.8 million, $5.6 million and $6.1 million as of December 31, 2015, 2016 and 2017, respectively. Although Nu Skin Japan has not specifically funded this obligation, as it is not required to do so, Nu Skin Japan believes it maintains adequate cash balances for this defined benefit pension plan. The Company recorded pension expense of $0.7 million, $0.9 million and $0.7 million for the years ended December 31, 2015, 2016 and 2017, respectively.

Executive Deferred Compensation Plan	12 Months Ended
Executive Deferred Compensation Plan	Dec. 31, 2017
Executive Deferred Compensation Plan [Abstract]
Executive Deferred Compensation Plan	17. Executive Deferred Compensation Plan The Company has an executive deferred compensation plan for select management personnel. Under this plan, the Company may make a contribution of up to 10% of a participant's salary. In addition, each participant has the option to defer a portion of their compensation up to a maximum of 80% of their base salary and 100% of their bonuses. Participant contributions are immediately vested. Company contributions vest 50% after ten years of service and 5% each year of service thereafter. In addition, any unvested company contributions will fully vest on the earlier of: (a) the participant attaining 60 years of age; and (b) death or disability. The Company recorded compensation expense of $2.3 million, $1.5 million and $1.5 million for the years ended December 31, 2015, 2016 and 2017, respectively, related to its contributions to the plan. The total long-term deferred compensation liability under the deferred compensation plan was $36.7 million and $43.2 million for the years ended December 31, 2016 and 2017, respectively, related to its contributions to the plan and is included in other long-term liabilities. All benefits under the deferred compensation plan are unsecured obligations of the Company. The Company has contributed assets to a "rabbi trust" for the payment of benefits under the deferred compensation plan. As the assets of the trust are available to satisfy the claims of general creditors if the Company becomes insolvent, the amounts held in the trust are accounted for as an investment on the Company's consolidated balance sheet of $32.3 million and $37.7 million for the years ended December 31, 2016 and 2017, respectively.

Derivative Financial Instruments

12 Months Ended

Dec. 31, 2017

Derivative Financial Instruments [Abstract]

Derivative Financial Instruments

18. Derivative Financial Instruments

The Company enters into non-designated foreign currency derivatives, primarily comprised of foreign currency forward contracts, for which hedge accounting does not apply. The changes in the fair market value of these non-designated derivatives are included in other income/expense in the Company's consolidated statements of income. The Company uses non-designated foreign currency derivatives to hedge foreign-currency-denominated intercompany transactions and to partially mitigate the impact of foreign-currency fluctuations. The fair value of the non-designated foreign currency derivatives is based on third-party quotes that management considered when determining the fair value.

As of December 31, 2017, the Company did not hold any non-designated derivative contracts. As of December 31, 2016, the Company held non-designated derivative contracts with notional amounts of 11.5 billion South Korean won ($9.5 million) as of December 31, 2016. The fair values of these non-designated derivative contracts were $0.5 million and zero as of December 31, 2016 and 2017, respectively.

The following table summarizes gains (losses) related to derivative instruments not designated as hedging instruments during the years ended December 31, 2015, 2016 and 2017 (U.S. dollars in thousands):

		Amount of Gain (Loss) Recognized in Income
		Year Ended December 31,
Derivatives not designated as hedging instruments:	Location of Gain (Loss) Recognized in Income	2015		2016		2017

Foreign currency contracts	Other income (expense)	$	38	$	39	$	(485	)

The Company designates as cash-flow hedges those foreign currency forward contracts it enters to hedge forecasted intercompany transactions that are subject to foreign currency exposures. Changes in the fair value of these forward contracts designated as cash-flow hedges are recorded as a component of accumulated other comprehensive income (loss) within shareholders' equity (deficit), and are recognized in the consolidated statement of income during the period which approximates the time the hedged transaction is settled.

As of December 31, 2017, the Company held forward contracts designated as foreign currency cash flow hedges with notional amounts totaling 600 million Japanese yen ($5.5 million), and 1.4 billion Japanese yen ($12.0 million) as of December 31, 2016 to hedge forecasted foreign-currency-denominated intercompany transactions. The fair value of these hedges were $0.9 million and $0.2 million as of December 31, 2016 and 2017, respectively. The contracts held at December 31, 2017 have maturities through June 2018, and accordingly, all unrealized gains and losses on foreign currency cash flow hedges included in accumulated other comprehensive loss will be recognized in current earnings over the next 6 months.

The following table summarizes gains (losses) related to derivative instruments recorded in other comprehensive income (loss) during the years ended December 31, 2015, 2016 and 2017 (U.S. dollars in thousands):

	Amount of Gain (Loss) Recognized in Other Comprehensive Loss
	Year Ended December 31,
Derivatives designated as hedging instruments:	2015		2016			2017

Foreign currency forward contracts related to intercompany license fee, product sales, and selling expense hedges	$	590	$	(1,423	)	$	(152	)

The following table summarizes gains (losses) relating to derivative instruments reclassified from accumulated other comprehensive loss into income during the years ended December 31, 2015, 2016 and 2017 (U.S. dollars in thousands):

		Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income
		Year Ended December 31,
Derivatives designated as hedging instruments:	Location of Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income	2015		2016			2017

Foreign currency forward contracts related to intercompany license fees and product sales hedges	Revenue	$	1,731	$	(1,088	)	$	119
Foreign currency forward contracts related to intercompany selling expense hedges	Selling expenses	$	397	$	(1,544	)	$	358

As of December 31, 2016 and 2017, there were $0.6 million and $0.1 million, respectively, of unrealized gains/(losses) included in accumulated other comprehensive loss related to foreign currency cash flow hedges. The remaining $84.7 million and $66.4 million as of December 31, 2016 and 2017, respectively, in accumulated other comprehensive loss are related to cumulative translation adjustments. The Company assesses hedge effectiveness at least quarterly. During the years ended December 31, 2016 and 2017, all hedges were determined to be effective.

The Company reports its derivatives at fair value as either other current assets or accrued expenses within its consolidated balance sheet. See Note 14, "Fair Value".

Supplemental Cash Flow Information	12 Months Ended
Supplemental Cash Flow Information	Dec. 31, 2017
Supplemental Cash Flow Information [Abstract]
Supplemental Cash Flow Information	19. Supplemental Cash Flow Information Cash paid for interest totaled $7.0 million, $11.6 million and $18.4 million for the years ended December 31, 2015, 2016 and 2017, respectively. Cash paid for income taxes totaled $49.8 million, $40.9 million and $78.1 million for the years ended December 31, 2015, 2016 and 2017, respectively.

Segment Information

12 Months Ended

Dec. 31, 2017

Segment Information [Abstract]

Segment Information

20. Segment Information

As a result of the Company's management changes in the first quarter of 2017, the Company concluded that the Chief Operating Decision Maker, as defined in ASC 280, is now comprised of the CEO, President and CFO. This change required the Company to reevaluate its determination of operating segments. The Company's operating segments are based on geographic regions that generate revenue and hold its long-lived assets. The Company sells and distributes its products through a global network of customers and sales leaders in approximately 50 markets. The Company has divided these markets into seven operating segments, which are the Company's reportable segments: Mainland China, Hong Kong/Taiwan, South Korea, Japan, South Asia/Pacific, Americas and EMEA. The seven reportable segments generate revenue from the sale of personal care products and nutritional supplements under the Nu Skin and Pharmanex brands, have similar business characteristics and align with how the CODM function began assessing performance and allocating resources in the first quarter of 2017.

Profitability by segment as reported under US GAAP is driven primarily by the Company's international taxation policies. Segment contribution, which is the Company's segment profitability metric presented in the table below, excludes certain intercompany charges, specifically royalties, license fees, transfer pricing, discrete charges and other miscellaneous items. These charges have been included in Corporate and other expenses. Corporate and other expenses also include costs related to the Company's executive and administrative offices, information technology, research and development, marketing and supply chain functions not recorded at the segment level.

The accounting policies of the segments are the same as those described in Note 1 – The Company. The Company evaluates the performance of its segments based on revenue and segment contribution. Each segment records direct expenses related to its employees and its operations.

Summarized financial information for the Company's reportable segments is shown in the following tables. Asset information is not reviewed or included with the Company's internal management reporting. Therefore, the Company has not disclosed asset information for each reportable segment.

Revenue by Segment

	Year Ended December 31,
(U.S. dollars in thousands)	2015		2016		2017

Mainland China	$	565,527	$	610,414	$	716,991
South Korea		422,341		413,696		361,692
Americas		329,668		276,590		317,380
South Asia/Pacific		321,971		296,758		299,980
Japan		264,214		279,042		256,085
Hong Kong/Taiwan		206,140		183,979		166,696
EMEA		137,186		147,318		160,275
Total	$	2,247,047	$	2,207,797	$	2,279,099

Segment Contribution

	Year Ended December 31,
(U.S. dollars in thousands)	2015			2016			2017

Mainland China	$	73,422		$	135,174		$	211,625
South Korea		130,516			117,142			100,964
Americas		62,937			44,390			47,040
South Asia/Pacific		68,949			71,365			68,141
Japan		51,181			59,175			51,372
Hong Kong/Taiwan		40,718			35,978			27,958
EMEA		11,172			10,386			11,749
Total segment contribution		438,895			473,610			518,849
Corporate and other		(194,193	)		(242,506	)		(244,366	)
Operating income		244,702			231,104			274,483
Other income (expense)		(32,743	)		(18,265	)		(8,916	)
Income before provision for income taxes	$	211,959		$	212,839		$	265,567

Depreciation and Amortization

	Year Ended December 31,
(U.S. dollars in thousands)	2015		2016		2017

Mainland China	$	18,503	$	16,775	$	15,122
South Korea		5,882		6,787		6,499
Americas		2,545		2,617		1,608
South Asia/Pacific		2,022		2,388		2,372
Japan		3,434		3,782		3,554
Hong Kong/Taiwan		2,132		2,507		1,395
EMEA		1,498		1,387		985
Corporate and other		35,349		36,154		40,029
Total	$	71,365	$	72,397	$	71,564

Capital Expenditures

	Year Ended December 31,
(U.S. dollars in thousands)	2015		2016		2017

Mainland China	$	21,998	$	13,656	$	4,539
South Korea		9,983		556		469
Americas		400		1,095		744
South Asia/Pacific		2,959		2,282		1,809
Japan		1,903		1,288		994
Hong Kong/Taiwan		1,345		634		1,350
EMEA		1,430		1,224		1,168
Corporate and other		16,604		29,486		49,083
Total	$	56,622	$	50,221	$	60,156

Revenue by Major Market

A major market is defined as one with total revenue greater than 10% of consolidated total revenue. Based on this criteria, the Company has identified three major markets: Mainland China, South Korea and Japan. There are approximately 50 other markets, each of which individually is less than 10%. The table below also includes the Company's country of domicile (the U.S.). No single customer accounted for 10% or more of net sales for the periods presented. Sales are recorded in the jurisdiction in which the transactions occurred:

	Year Ended December 31,
(U.S. dollars in thousands)	2015		2016		2017

Mainland China	$	565,527	$	610,414	$	716,991
South Korea		422,341		413,696		361,692
Japan		264,214		279,042		256,085
United States		243,748		201,239		218,734
All others		751,217		703,406		725,597
Total	$	2,247,047	$	2,207,797	$	2,279,099

Revenue by Product Line

	Year Ended December 31,
(U.S. dollars in thousands)	2015		2016		2017

Nu Skin	$	1,363,539	$	1,308,135	$	1,456,386
Pharmanex		877,924		892,738		817,230
Other		5,584		6,924		5,483
Total	$	2,247,047	$	2,207,797	$	2,279,099

Long-Lived Assets by Major Market

A major market is defined as a market with long-lived assets greater than 10% of consolidated long-lived assets and also includes the Company's country of domicile (the U.S.). Long-lived assets in Mainland China consist primarily of property, plant and equipment related to manufacturing, distribution facilities and the Mainland China headquarters. Long-lived assets in the U.S. consist primarily of property, plant and equipment, including the Company's corporate offices and distribution facilities. Long-lived assets by major market are set forth below for the periods ended December 31, 2016 and 2017:

	Year Ended December 31,
(U.S. dollars in thousands)	2015		2016		2017

United States	$	271,058	$	283,868	$	302,884
Mainland China		110,839		97,867		97,046
South Korea		48,702		41,545		42,211
Japan		13,587		11,517		9,342
All others		10,351		9,935		13,104
Total	$	454,537	$	444,732	$	464,587

Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Dec. 31, 2017
Commitments and Contingencies [Abstract]
Commitments and Contingencies	21. Commitments and Contingencies The Company is subject to government regulations pertaining to product formulation, labeling and packaging, product claims and advertising, and the Company's direct selling system. The Company is also subject to the jurisdiction of numerous foreign tax and customs authorities. Any assertions or determination that either the Company or the Company's sales force is not in compliance with existing statutes, laws, rules or regulations could have a material adverse effect on the Company's operations. In addition, in any market or jurisdiction, the adoption of new statutes, laws, rules or regulations or changes in the interpretation of existing statutes, laws, rules or regulations could have a material adverse effect on the Company and its operations. Although management believes that the Company is in compliance in all material respects with the statutes, laws, rules and regulations of every jurisdiction in which it operates, no assurance can be given that the Company's compliance with applicable statutes, laws, rules and regulations will not be challenged by foreign authorities or that such challenges will not have a material adverse effect on the Company's financial position or results of operations or cash flows. The Company and its Subsidiaries are defendants in litigation, investigations and other proceedings involving various matters. In the opinion of the Company's management, based upon advice of its counsel handling such litigation, investigations and other proceedings, adverse outcomes, if any, will not likely result in a material effect on the Company's consolidated financial condition, results of operations or cash flows. The Company is subject to regular audits by federal, state and foreign tax authorities. These audits may result in additional tax liabilities. The Company believes it has appropriately provided for income taxes for all years. Several factors drive the calculation of its tax reserves. Some of these factors include: (i) the expiration of various statutes of limitations; (ii) changes in tax law and regulations; (iii) issuance of tax rulings; and (iv) settlements with tax authorities. Changes in any of these factors may result in adjustments to the Company's reserves, which would impact its reported financial results.

Dividends per Share	12 Months Ended
Dividends per Share	Dec. 31, 2017
Dividends per Share [Abstract]
Dividends per Share	22. Dividends per Share Quarterly cash dividends for the years ended December 31, 2016 and 2017 totaled $78.4 million and $76.1 million or $0.355 per share in all quarters of 2016 and $0.36 for all quarters of 2017. The board of directors has declared a quarterly cash dividend of $0.365 per share of Class A common stock to be paid on March 14, 2018 to stockholders of record on February 26, 2018.

Other Income (Expense), Net	12 Months Ended
Other Income (Expense), Net	Dec. 31, 2017
Other Income (Expense), Net [Abstract]
Other Income (Expense), Net	23. Other Income (Expense), Net Other income (expense), net was $32.7 million, $18.3 million and $8.9 million of expense in 2015, 2016 and 2017, respectively. In 2015, the Company recorded a charge of $10.2 million related to a new foreign exchange mechanism for Venezuela currency and incurred foreign currency translation expenses of $17.0 million. Other income (expense), net also includes $7.9 million, $15.6 million and $22.2 million in interest expense during 2015, 2016 and 2017, respectively. The Company cannot estimate the degree to which its operations will be impacted in the future, but it remains subject to these currency risks. However, the majority of these transaction losses are non-cash, non-operating losses.

Cost of Sales	12 Months Ended
Cost of Sales	Dec. 31, 2017
Cost of Sales [Abstract]
Cost of Sales	24. Cost of Sales The Tokyo District Court and, on appeal in 2017, the Tokyo High Court have upheld the Japan customs authorities' customs assessments related to the importation of several of the Company's products into Japan. We have appealed the High Court's decision to the Japan Supreme Court. As previously disclosed, the Company already recorded a charge of $31.4 million to cost of sales in the first quarter of 2016, when the District Court issued its decision. This charge represents the full amount being disputed. It was a non-cash item because the Company was previously required to pay the assessments.

Acquisitions	12 Months Ended
Acquisitions	Dec. 31, 2017
Acquisitions [Abstract]
Acquisitions	25. Acquisitions Vertical Eden, LLC In the first quarter of 2016, the Company purchased 70% of Vertical Eden, LLC, an early-stage company in the warehouse growing market, based in Alpine, Utah, for $3.3 million in cash and contingent consideration valued at $1.5 million which resulted in $2.5 million of goodwill. In the second quarter of 2017, the Company purchased the remaining 30% of Vertical Eden for $12.5 million in cash. The purchase of Vertical Eden includes specialized technology in remote programming and management of the entire crop growing cycle. As a result of this acquisition, the Company recorded approximately $4.4 million of intangible assets which are being amortized over the useful lives of 3 to 7 years. Treviso, LLC On February 28, 2017, the Company purchased a 35% membership interest in Treviso, LLC, which owns a manufacturing company, for a purchase price of $21.0 million and a possible earnout of $1.0 million. The purchase price included $12.6 million in cash and $8.4 million in the Company's stock (169,560 shares based on the closing stock price of $49.54 per share on February 28, 2017). Dr. Dana Beauty, LLC In the third quarter of 2017, the Company acquired certain assets of Dr. Dana Beauty, LLC for $7.0 million in cash. The acquisition, which was accounted for as an asset acquisition, includes contingent consideration of $4.3 million, which is considered a Level 3 liability. The assets acquired include trademarks, product formulas and other intellectual property primarily related to nail treatment.

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2017
Subsequent Events [Abstract]
Subsequent Events	26. Subsequent Events On January 22, 2018, the Company acquired the remaining 73% ownership in Innuvate Health Sciences, LLC ("Innuvate"), which owns a 92% interest in a nutritional product manufacturer. Prior to this acquisition, the Company owned 27% of Innuvate and accounted for it using the equity method. The remaining 8% ownership in the manufacturer will continue to be held by an unrelated third party. Under the terms of the agreement, the Company has agreed to pay $23.5 million in cash and shares of the Company in exchange for the 73% ownership in Innuvate, subject to adjustment for certain closing items. On February 12, 2018, the Company acquired the remaining 65% ownership in Treviso, LLC ("Treviso"), making Treviso a wholly owned subsidiary of the Company. Treviso is a personal care product manufacturer. Prior to this acquisition, the Company owned 35% of Treviso and accounted for it using the equity method. Under the terms of the purchase agreement, the Company has agreed to pay $54.9 million in cash and shares of the Company in exchange for the 65% ownership in Treviso, subject to adjustment for certain closing items. On February 12, 2018, the Company acquired 100% ownership in L&W Holdings, Inc. ("L&W") making L&W a wholly owned subsidiary of the Company. L&W is a packaging supplier company. Under the terms of the purchase agreement, the Company has agreed to pay $25.0 million in shares of the Company in exchange for 100% ownership in L&W, subject to adjustment for certain closing items. The Company is currently in the process of valuing the assets acquired and liabilities assumed as part of these transactions. Given the timing of the close of the transactions, the Company is not yet able to provide the amounts to be recognized for the major classes of assets acquired and liabilities assumed, as well as, other related disclosures. The Company will disclose this and other related information in its Form 10-Q for the quarter ended March 31, 2018.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2017

Summary of Significant Accounting Policies [Abstract]

Consolidation

The consolidated financial statements include the accounts of the Company and the Subsidiaries. All significant intercompany accounts and transactions are eliminated in consolidation.

Use of estimates

Cash and cash equivalents

Cash equivalents are short-term, highly liquid instruments with original maturities of 90 days or less.

Inventories

Inventories consist of the following (U.S. dollars in thousands):

	December 31,
	2016		2017

Raw materials	$	108,276	$	87,683
Finished goods		141,660		165,771
	$	249,936	$	253,454

Reserves of inventories consist of the following (U.S. dollars in thousands):

	2015			2016			2017

Beginning balance	$	56,034		$	20,744		$	7,995
Additions		38,605			24,906			16,382
Write-offs		(73,895	)		(37,655	)		(16,296	)
Ending balance	$	20,744		$	7,995		$	8,081

Goodwill and other intangible assets

Property and equipment are stated at cost less accumulated depreciation. Depreciation is recorded using the straight-line method over the following estimated useful lives:

	Buildings		39 years
	Furniture and fixtures		5 - 7 years
	Computers and equipment		3 -- 5 years
	Leasehold improvements		Shorter of estimated useful life or lease term
	Scanners		3 years
	Vehicles		3 - 5 years

No impairment charges were recorded for goodwill or intangibles during the periods presented.

Revenue recognition

Shipping and handling costs

Shipping and handling costs are recorded as cost of sales and are expensed as incurred.

Advertising expenses

Advertising costs are expensed as incurred. Advertising expense incurred for the years ended December 31, 2015, 2016 and 2017 totaled $11.0 million, $15.9 million and $15.6 million, respectively.

Selling expenses

Research and development

Deferred tax assets and liabilities

Uncertain tax positions

A reconciliation of the beginning and ending amount of unrecognized tax benefits included in other liabilities is as follows (U.S. dollars in thousands):

	2015			2016			2017

Gross balance at January 1	$	5,987		$	7,772		$	5,290
Increases related to prior year tax positions		1,677			185		─
Decreases related to prior year tax positions	─			─				(277	)
Increases related to current year tax positions		1,119			918			669
Settlements	─				(3,369	)		(159	)
Decreases due to lapse of statutes of limitations		(667	)		(252	)		(187	)
Currency adjustments		(344	)		36			178
Gross balance at December 31	$	7,772		$	5,290		$	5,514

Net income per share

Foreign currency translation

Classification of Venezuela as a Highly Inflationary Economy and Devaluation of Its Currency

Fair value of financial instruments

•	Level 1 – quoted prices in active markets for identical assets or liabilities;

•	Level 2 – inputs, other than the quoted prices in active markets, that are observable either directly or indirectly;

•	Level 3 – unobservable inputs based on the Company's own assumptions.

Stock-based compensation

Reporting comprehensive income

Accounting for derivative instruments and hedging activities

The Company recognizes all derivatives as either assets or liabilities, with the instruments measured at fair value.

Recent accounting pronouncements

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2017

Summary of Significant Accounting Policies [Abstract]

Inventories

Inventories consist of the following (U.S. dollars in thousands):

	December 31,
	2016		2017

Raw materials	$	108,276	$	87,683
Finished goods		141,660		165,771
	$	249,936	$	253,454

Inventory Reserves

Reserves of inventories consist of the following (U.S. dollars in thousands):

	2015			2016			2017

Beginning balance	$	56,034		$	20,744		$	7,995
Additions		38,605			24,906			16,382
Write-offs		(73,895	)		(37,655	)		(16,296	)
Ending balance	$	20,744		$	7,995		$	8,081

Estimated Useful Lives

Depreciation is recorded using the straight-line method over the following estimated useful lives:

	Buildings		39 years
	Furniture and fixtures		5 - 7 years
	Computers and equipment		3 -- 5 years
	Leasehold improvements		Shorter of estimated useful life or lease term
	Scanners		3 years
	Vehicles		3 - 5 years

Unrecognized Tax Benefits

A reconciliation of the beginning and ending amount of unrecognized tax benefits included in other liabilities is as follows (U.S. dollars in thousands):

	2015			2016			2017

Gross balance at January 1	$	5,987		$	7,772		$	5,290
Increases related to prior year tax positions		1,677			185		─
Decreases related to prior year tax positions	─			─				(277	)
Increases related to current year tax positions		1,119			918			669
Settlements	─				(3,369	)		(159	)
Decreases due to lapse of statutes of limitations		(667	)		(252	)		(187	)
Currency adjustments		(344	)		36			178
Gross balance at December 31	$	7,772		$	5,290		$	5,514

Prepaid Expenses and Other (Tables)

12 Months Ended

Dec. 31, 2017

Prepaid Expenses and Other [Abstract]

Prepaid Expenses and Other

Prepaid expenses and other consist of the following (U.S. dollars in thousands):

	December 31,
	2016		2017

Deferred charges	$	9,319	$	4,256
Prepaid income taxes		6,799	─
Prepaid inventory and import costs		10,857		9,397
Prepaid rent, insurance and other occupancy costs		13,398		14,558
Prepaid promotion and event cost		4,126		3,581
Prepaid other taxes		4,778		5,559
Forward contracts		1,371		158
Deposits		1,079		1,147
Other		13,349		14,237
	$	65,076	$	52,893

Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2017

Property and Equipment

Property and equipment are comprised of the following (U.S. dollars in thousands):

	December 31,
	2016			2017

Land	$	33,158		$	33,667
Buildings		266,436			274,632
Construction in progress⁽¹⁾		31,124			53,125
Furniture and fixtures		82,194			95,378
Computers and equipment		143,014			156,994
Leasehold improvements		109,863			123,479
Scanners		10,578			11,212
Vehicles		2,090			2,339
		678,457			750,826
Less: accumulated depreciation		(233,725	)		(286,239	)
	$	444,732		$	464,587

⁽¹⁾

Goodwill (Tables)

12 Months Ended

Dec. 31, 2017

Indefinite Life Intangible Assets

The following table presents goodwill allocated to the Company's reportable segments for the periods ended December 30, 2017 and December 31, 2016 (U.S. dollars in thousands):

	December 31, 2016⁽¹⁾		December 31, 2017

Mainland China	$	32,179	$	32,179
South Korea		29,261		29,261
Americas		9,449		9,449
South Asia/Pacific		18,537		18,537
Japan		16,019		16,019
Hong Kong/Taiwan		6,634		6,634
EMEA		2,875		2,875
Total	$	114,954	$	114,954

⁽¹⁾

Goodwill was recast to reflect current period presentation by geographic region at December 31, 2016.

Other Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2017

Other Intangible Assets [Abstract]

Other intangible assets consist of the following (U.S. dollars in thousands):

	Carrying Amount at December 31,
Indefinite life intangible assets:	2016		2017

Trademarks and trade names	$	24,599	$	24,599
Other indefinite lived intangibles		3,763		3,763
	$	28,362	$	28,362

Finite Life Intangible Assets

	December 31, 2016				December 31, 2017
Finite life intangible assets:	Gross Carrying Amount		Accumulated Amortization		Gross Carrying Amount		Accumulated Amortization		Weighted-average Amortization Period

Scanner technology	$	46,482	$	36,624	$	46,482	$	39,657	18 years
Developed technology		22,500		18,383		22,500		19,207	20 years
Distributor network		11,598		11,598		11,598		11,598	15 years
Trademarks		2,592		1,011		2,785		1,197	15 years
Other		46,219		26,584		57,550		29,971	8 years
	$	129,391	$	94,200	$	140,915	$	101,630	15 years

Future Amortization Expense

The estimated annual amortization expense for each of the five succeeding fiscal years are as follows (U.S. dollars in thousands):

Year Ending December 31,

	2018	$	8,978
	2019		8,876
	2020		4,898
	2021		4,148
	2022		5,201

Other Assets (Tables)

12 Months Ended

Dec. 31, 2017

Other Assets [Abstract]

Other Assets

Other assets consist of the following (U.S. dollars in thousands):

	December 31,
	2016		2017

Deferred taxes	$	35,752	$	33,785
Deposits for noncancelable operating leases		38,858		43,375
Cash surrender value for life insurance policies		32,286		37,737
Other		29,573		49,998
	$	136,469	$	164,895

Accrued Expenses (Tables)

12 Months Ended

Dec. 31, 2017

Accrued Expenses [Abstract]

Accrued Expenses

Accrued expenses consist of the following (U.S. dollars in thousands):

	December 31,
	2016		2017

Accrued sales force commissions and other payments	$	126,153	$	151,549
Accrued income taxes	─			13,075
Accrued other taxes		31,748		44,580
Accrued payroll and other employee expenses		25,412		38,167
Accrued payable to vendors		28,456		29,874
Accrued royalties		4,767		2,623
Sales return reserve		6,125		4,523
Deferred revenue		13,494		12,669
Other		38,868		22,129
	$	275,023	$	319,189

Other Liabilities (Tables)

12 Months Ended

Dec. 31, 2017

Other Liabilities [Abstract]

Other Liabilities

Other liabilities consist of the following (U.S. dollars in thousands):

	December 31,
	2016		2017

Deferred tax liabilities	$	643	$	36,718
Reserve for other tax liabilities		6,264		7,163
Liability for deferred compensation plan		36,730		43,248
Pension plan benefits reserve		5,631		6,359
Build to suit – financing obligation		9,543		10,290
Deferred rent and deferred tenant incentives		5,952		6,389
Asset retirement obligation		5,682		6,578
Other		6,354		10,371
	$	76,799	$	127,116

Long-Term Debt (Tables)

12 Months Ended

Dec. 31, 2017

Long-Term Debt [Abstract]

Convertible Note

The net carrying amount of the Liability Component is as follows (U.S. dollars in thousands):

	December 31, 2017

Principal	$	210,000
Unamortized debt discount (conversion option)		(7,078	)
Total long-term debt, net		202,922
Unamortized debt discount (issuance costs)		(4,050	)
Net carrying amount	$	198,872

Debt Facilities

The following table summarizes the Company's debt facilities as of December 31, 2016 and 2017:

Facility or Arrangement	Original Principal Amount	Balance as of December 31, 2016	Balance as of December 31, 2017⁽¹⁾⁽²⁾	Interest Rate	Repayment terms

Credit Agreement term loan facility:

U.S. dollar denominated:	$127.5 million	$108.4 million	$94.8 million	Variable 30 day: 4.319%	One half of the principal amount payable in increasing quarterly installments over a five-year period beginning on December 31, 2014, with the remainder payable at the end of the five-year term.

Japanese yen denominated:	6.6 billion yen	5.6 billion yen ($47.9 million as of December 31, 2016)	4.9 billion yen ($43.5 million as of December 31, 2017)	Variable 30 day: 2.75%	One half of the principal amount payable in increasing quarterly installments over a five-year period beginning on December 31, 2014, with the remainder payable at the end of the five-year term.

Credit Agreement revolving credit facility:

		$47.5 million	$47.5 million	Variable 30 day: 4.319%	Revolving line of credit expires October 2019.

South Korea subsidiary loan:	$20.0 million	$10.0 million	─	1.12%	Loan was paid off in March 2017.

Japan subsidiary loan:	2.0 billion yen	1.3 billion yen ($11.4 million as of December 31, 2016)	0.7 billion yen ($5.9 million as of December 31, 2017)	0.66%	Payable in semi-annual installments over three years that began on January 31, 2016.

Convertible note	$210.0 million	$210.0 million	$210.0 million	4.75%	Principal amount payable on June 15, 2020.

⁽¹⁾

⁽²⁾

Maturities of Long-Term Debt

Maturities of all long-term debt at December 31, 2017, based on the year-end exchange rate, are as follows (U.S. dollars in thousands):

Year Ending December 31,

2018	$	77,840
2019		113,928
2020		210,000
2021	─
2022	─
Thereafter	─
Total⁽¹⁾	$	401,768

⁽¹⁾	The carrying value of the debt reflects the amounts stated in the above table less a debt discount of $13.1 million, which is not reflected in this table.

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21475-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(e),(f))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21538-112644

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21506-112644

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28541-108399

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21521-112644

+ Details

Lease and Financing Obligations (Tables)

12 Months Ended

Dec. 31, 2017

Lease and Financing Obligations [Abstract]

Minimum Future Operating Leases and Financing Obligations

Minimum future operating leases and financing obligations at December 31, 2017 are as follows (U.S. dollars in thousands):

Year Ending December 31,	Operating Leases		Financing Obligations

2018	$	41,788	$	736
2019		27,088		758
2020		14,907		781
2021		10,036		790
2022		7,672		804
Thereafter		13,250		2,027
Total minimum lease payments	$	114,741	$	5,896

Capital Stock (Tables)

12 Months Ended

Dec. 31, 2017

Capital Stock [Abstract]

Weighted-Average Common Shares Outstanding

The following is a reconciliation of the weighted-average common shares outstanding for purposes of computing basic and diluted net income per share (in thousands):

	Year Ended December 31,
	2015		2016		2017

Basic weighted-average common shares outstanding		57,997		55,412		52,806
Effect of dilutive securities: Stock awards and options		1,060		683		1,110
Convertible note		—		2		936
Diluted weighted-average common shares outstanding		59,057		56,097		54,852

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2017

Stock-Based Compensation [Abstract]

Stock Option Valuation Assumptions

The fair value of stock option awards was estimated using the Black-Scholes option-pricing model with the following assumptions and weighted-average fair values as follows:

	December 31,
Stock Options:	2015		2016		2017

Weighted-average grant date fair value of grants	$	16.26	$	12.59	$	18.84
Risk-free interest rate⁽¹⁾		1.7%		1.4%		2.1%
Dividend yield⁽²⁾		2.1%		2.3%		2.5%
Expected volatility⁽³⁾		46.8%		47.9%		48.2%
Expected life in months⁽⁴⁾	65 months		68 months		68 months

⁽¹⁾

The risk-free interest rate is based upon the rate on a zero-coupon U.S. Treasury bill, for periods within the contractual life of the option, in effect at the time of the grant.

⁽²⁾

The dividend yield is based on the average of historical stock prices and actual dividends paid.

⁽³⁾

Expected volatility is based on the historical volatility of the Company's stock price, over a period similar to the expected life of the option.

⁽⁴⁾

The expected term of the option is based on the historical employee exercise behavior, the vesting terms of the respective option, and a contractual life of either seven or ten years.

Stock Options

Options under the plans as of December 31, 2017 and changes during the year ended December 31, 2017 were as follows:

	Shares (in thousands)			Weighted-average Exercise Price		Weighted- average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in thousands)

Options activity – service based
Outstanding at December 31, 2016		2,207.0		$	39.93
Granted	─			─
Exercised		(324.4	)		34.71
Forfeited/cancelled/expired		(489.7	)		43.85
Outstanding at December 31, 2017		1,392.9			39.76		4.36	$	41,756
Exercisable at December 31, 2017		725.5			43.14		3.55		20,237

Options activity – performance based
Outstanding at December 31, 2016		3,725.9		$	58.23
Granted		298.0			50.93
Exercised		(853.0	)		30.86
Forfeited/cancelled/expired		(869.4	)		70.17
Outstanding at December 31, 2017		2,301.5			62.89		3.61	$	26,206
Exercisable at December 31, 2017		294.1			35.58		4.17		9,601

Options activity – all options
Outstanding at December 31, 2016		5,932.9		$	51.42
Granted		298.0			50.93
Exercised		(1,177.4	)		31.92
Forfeited/cancelled/expired		(1,359.1	)		60.69
Outstanding at December 31, 2017		3,694.4			54.17		3.90	$	67,962
Exercisable at December 31, 2017		1,019.6			40.96		3.73		29,838

Stock Options Exercised

Cash proceeds, tax benefits and intrinsic value related to total stock options exercised during 2015, 2016 and 2017, were as follows (U.S. dollars in thousands):

	December 31,
	2015		2016		2017

Cash proceeds from stock options exercised	$	13,041	$	15,707	$	26,980
Tax benefit realized for stock options exercised		4,451		3,840		6,457
Intrinsic value of stock options exercised		12,085		30,587		42,749

Nonvested Restricted Stock Awards

Nonvested restricted stock awards as of December 31, 2017 and changes during the year ended December 31, 2017 were as follows:

	Number of Shares (in thousands)			Weighted-average Grant Date Fair Value

Nonvested at December 31, 2016		596.4		$	53.62

Granted		261.6			50.95
Vested		(203.2	)		53.94
Forfeited		(91.9	)		60.30

Nonvested at December 31, 2017		562.9			51.17

Fair Value (Tables)

12 Months Ended

Dec. 31, 2017

Fair Value [Abstract]

Assets and Liabilities Measured at Fair Value on a Recurring Basis

The following tables present the fair value hierarchy for those assets and liabilities measured at fair value on a recurring basis (U.S. dollars in thousands):

	Fair Value at December 31, 2016
	Level 1		Level 2		Level 3		Total

Financial assets (liabilities):
Cash equivalents and current investments	$	50,307	$	─	$	─	$	50,307
Other long-term assets		2,782	─		─			2,782
Forward contracts	─			1,371	─			1,371
Life insurance contracts	─		─			32,286		32,286
Total	$	53,089	$	1,371	$	32,286	$	86,746

	Fair Value at December 31, 2017
	Level 1		Level 2		Level 3		Total

Financial assets (liabilities):
Cash equivalents and current investments	$	36,531	$	─	$	─	$	36,531
Other long-term assets		3,726	─		─			3,726
Forward contracts	─			158	─			158
Life insurance contracts	─		─			37,737		37,737
Total	$	40,257	$	158	$	37,737	$	78,152

Changes in Fair Value of Level 3 Marketable Securities

The following table provides a summary of changes in fair value of the Company's Level 3 marketable securities (U.S. dollars in thousands):

Life Insurance Contracts	2016			2017

Beginning balance at January 1	$	27,292		$	32,287
Actual return on plan assets:
Relating to assets still held at the reporting date		2,196			4,917
Purchases and issuances		3,051			895
Sales and settlements		(252	)		(362	)
Transfers into Level 3	─			─
Ending balance at December 31	$	32,287		$	37,737

- Definition

Tabular disclosure of financial instruments measured at fair value, including those classified in shareholders' equity measured on a recurring or nonrecurring basis. Disclosures include, but are not limited to, fair value measurements recorded and the reasons for the measurements, level within the fair value hierarchy in which the fair value measurements are categorized and transfers between levels 1 and 2. Nonrecurring fair value measurements are those that are required or permitted in the statement of financial position in particular circumstances.

+ References + Details

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Taxes [Abstract]

Consolidated Income Before Provision for Income Taxes

Consolidated income before provision for income taxes consists of the following for the years ended December 31, 2015, 2016 and 2017 (U.S. dollars in thousands):

	2015		2016			2017

U.S.	$	134,473	$	(19,119	)	$	1,135
Foreign		77,486		231,958			264,432
Total	$	211,959	$	212,839		$	265,567

Current and Deferred Taxes

The provision for current and deferred taxes for the years ended December 31, 2015, 2016 and 2017 consists of the following (U.S. dollars in thousands):

	2015			2016			2017
Current
Federal	$	6,328		$	─		$	(14,358	)
State		1,483			(718	)		1,814
Foreign		50,403			70,652			104,688
		58,214			69,934			92,144
Deferred
Federal		16,556			(27,171	)		45,593
State		(674	)		1,104			(2,273	)
Foreign		4,817			25,886			666
		20,699			(181	)		43,986
Provision for income taxes	$	78,913		$	69,753		$	136,130

Deferred Tax Assets and Liabilities

The principal components of deferred taxes are as follows (U.S. dollars in thousands):

	Year Ended December 31,
	2016			2017
Deferred tax assets:
Inventory differences	$	2,521		$	2,861
Foreign tax credit and other foreign benefits		145,169			52,408
Stock-based compensation		11,470			6,327
Accrued expenses not deductible until paid		32,796			39,326
Foreign currency exchange		4,826			2,001
Net operating losses		9,584			5,230
Capitalized research and development		358			197
Other		1,063			211
Gross deferred tax assets		207,787			108,561
Deferred tax liabilities:
Foreign currency exchange		105			874
Foreign withholding taxes	─				29,018
Intangibles step-up		12,107			6,568
Overhead allocation to inventory		4,820			3,977
Amortization of intangibles		19,091			11,475
Foreign outside basis in controlled foreign corporation		106,846		─
Other		20,572			2,676
Gross deferred tax liabilities		163,541			54,588
Valuation allowance		(9,137	)		(56,906	)
Deferred taxes, net	$	35,109		$	(2,933	)

Deferred Tax Asset Valuation Adjustments

The deferred tax asset valuation adjustments for the years ended December 31, 2015, 2016 and 2017 are as follows (U.S. dollars in thousands):

	Year Ended December 31,
	2015			2016			2017

Balance at the beginning of period	$	35,999		$	49,271		$	9,137
Additions charged to cost and expenses		12,948			692			53,983	⁽⁵⁾
Decreases		(2,943	)⁽¹⁾		(40,442	)⁽⁴⁾		(6,400	)⁽⁶⁾
Adjustments		3,267	⁽²⁾		(384	)⁽²⁾		186	⁽²⁾
Balance at the end of the period	$	49,271	⁽³⁾	$	9,137		$	56,906

⁽¹⁾

Decreases in valuation allowance due to lapse in statute of limitation of the net operating losses carryforward which had no impact to the income statement.

⁽²⁾

Represents the net currency effects of translating valuation allowances at current rates of exchange.

⁽³⁾

The increase was due primarily to the deferred tax assets created by the unrealized loss in Venezuela for which the Company set up a full valuation allowance.

⁽⁴⁾

⁽⁵⁾

Increase in valuation is due primarily to the $52.0 million that was recorded on the foreign tax credit carryforward. The additional amount is due to net operating losses in foreign markets.

⁽⁶⁾

Decrease is due primarily to the write-off of Brazil deferred tax assets, which had no impact to the income statement, as a valuation allowance had been previously recorded against the asset.

Deferred Taxes, Net on a Jurisdiction Basis

The components of deferred taxes, net on a jurisdiction basis are as follows (U.S. dollars in thousands):

	Year Ended December 31,
	2016		2017

Net noncurrent deferred tax assets	$	35,752	$	33,785

Net noncurrent deferred tax liabilities		643		36,718

Deferred taxes, net	$	35,109	$	(2,933	)

Reconciliation of Statutory to Effective Tax Rate

The actual tax rate for the years ended December 31, 2015, 2016 and 2017 compared to the statutory U.S. Federal tax rate is as follows:

	Year Ended December 31,
	2015			2016			2017

Income taxes at statutory rate		35.00	%		35.00	%		35.00	%
Indefinite reinvestment		.92			(1.98	)		2.75
Excess tax benefit from equity award	─			─				(2.38	)
Non-deductible expenses		0.09			0.11			0.17
Controlled foreign corporation losses		1.09			(2.63	)		(0.13	)
Valuation allowance recognized foreign tax credit	─			─				19.59
Write-off outside basis DTL	─			─				(2.89	)
Revaluation of deferred taxes	─			─				(1.28	)
Section 987 implementation	─				2.69		─
Other		0.13			(0.42	)		0.43
		37.23	%		32.77	%		51.26	%

Derivative Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2017

Derivative Financial Instruments [Abstract]

Gains (Losses) Related to Derivative Instruments Not Designated as Hedging Instruments

		Amount of Gain (Loss) Recognized in Income
		Year Ended December 31,
Derivatives not designated as hedging instruments:	Location of Gain (Loss) Recognized in Income	2015		2016		2017

Foreign currency contracts	Other income (expense)	$	38	$	39	$	(485	)

Gains (Losses) Related to Derivative Instruments Designated as Cash Flow Hedges

	Amount of Gain (Loss) Recognized in Other Comprehensive Loss
	Year Ended December 31,
Derivatives designated as hedging instruments:	2015		2016			2017

Foreign currency forward contracts related to intercompany license fee, product sales, and selling expense hedges	$	590	$	(1,423	)	$	(152	)

		Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income
		Year Ended December 31,
Derivatives designated as hedging instruments:	Location of Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income	2015		2016			2017

Foreign currency forward contracts related to intercompany license fees and product sales hedges	Revenue	$	1,731	$	(1,088	)	$	119
Foreign currency forward contracts related to intercompany selling expense hedges	Selling expenses	$	397	$	(1,544	)	$	358

Segment Information (Tables)

12 Months Ended

Dec. 31, 2017

Segment Information [Abstract]

Revenue by Segment

	Year Ended December 31,
(U.S. dollars in thousands)	2015		2016		2017

Mainland China	$	565,527	$	610,414	$	716,991
South Korea		422,341		413,696		361,692
Americas		329,668		276,590		317,380
South Asia/Pacific		321,971		296,758		299,980
Japan		264,214		279,042		256,085
Hong Kong/Taiwan		206,140		183,979		166,696
EMEA		137,186		147,318		160,275
Total	$	2,247,047	$	2,207,797	$	2,279,099

Segment Contribution

	Year Ended December 31,
(U.S. dollars in thousands)	2015			2016			2017

Mainland China	$	73,422		$	135,174		$	211,625
South Korea		130,516			117,142			100,964
Americas		62,937			44,390			47,040
South Asia/Pacific		68,949			71,365			68,141
Japan		51,181			59,175			51,372
Hong Kong/Taiwan		40,718			35,978			27,958
EMEA		11,172			10,386			11,749
Total segment contribution		438,895			473,610			518,849
Corporate and other		(194,193	)		(242,506	)		(244,366	)
Operating income		244,702			231,104			274,483
Other income (expense)		(32,743	)		(18,265	)		(8,916	)
Income before provision for income taxes	$	211,959		$	212,839		$	265,567

Depreciation and Amortization and Capital Expenditures

Depreciation and Amortization

	Year Ended December 31,
(U.S. dollars in thousands)	2015		2016		2017

Mainland China	$	18,503	$	16,775	$	15,122
South Korea		5,882		6,787		6,499
Americas		2,545		2,617		1,608
South Asia/Pacific		2,022		2,388		2,372
Japan		3,434		3,782		3,554
Hong Kong/Taiwan		2,132		2,507		1,395
EMEA		1,498		1,387		985
Corporate and other		35,349		36,154		40,029
Total	$	71,365	$	72,397	$	71,564

Capital Expenditures

	Year Ended December 31,
(U.S. dollars in thousands)	2015		2016		2017

Mainland China	$	21,998	$	13,656	$	4,539
South Korea		9,983		556		469
Americas		400		1,095		744
South Asia/Pacific		2,959		2,282		1,809
Japan		1,903		1,288		994
Hong Kong/Taiwan		1,345		634		1,350
EMEA		1,430		1,224		1,168
Corporate and other		16,604		29,486		49,083
Total	$	56,622	$	50,221	$	60,156

Revenue by Major Market

	Year Ended December 31,
(U.S. dollars in thousands)	2015		2016		2017

Mainland China	$	565,527	$	610,414	$	716,991
South Korea		422,341		413,696		361,692
Japan		264,214		279,042		256,085
United States		243,748		201,239		218,734
All others		751,217		703,406		725,597
Total	$	2,247,047	$	2,207,797	$	2,279,099

Revenue by Product Line

	Year Ended December 31,
(U.S. dollars in thousands)	2015		2016		2017

Nu Skin	$	1,363,539	$	1,308,135	$	1,456,386
Pharmanex		877,924		892,738		817,230
Other		5,584		6,924		5,483
Total	$	2,247,047	$	2,207,797	$	2,279,099

Long-Lived Assets by Major Market

	Year Ended December 31,
(U.S. dollars in thousands)	2015		2016		2017

United States	$	271,058	$	283,868	$	302,884
Mainland China		110,839		97,867		97,046
South Korea		48,702		41,545		42,211
Japan		13,587		11,517		9,342
All others		10,351		9,935		13,104
Total	$	454,537	$	444,732	$	464,587

The Company (Details)	12 Months Ended
The Company (Details)	Dec. 31, 2017 Segment
The Company [Abstract]
Number of segments	7

Summary of Significant Accounting Policies, Inventories (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Inventories [Abstract]
Raw materials	$ 87,683	$ 108,276
Finished goods	165,771	141,660
Inventories	253,454	249,936
Inventory Valuation Reserve [Member]
Valuation Allowance [Roll Forward]
Beginning balance	7,995	20,744	$ 56,034
Additions	16,382	24,906	38,605
Write-offs	(16,296)	(37,655)	(73,895)
Ending balance	$ 8,081	$ 7,995	$ 20,744

Summary of Significant Accounting Policies, Property and Equipment (Details)	12 Months Ended
	Dec. 31, 2017
Building [Member]
Property and Equipment [Abstract]
Useful life	39 years
Furniture and Fixtures [Member] \| Minimum [Member]
Property and Equipment [Abstract]
Useful life	5 years
Furniture and Fixtures [Member] \| Maximum [Member]
Property and Equipment [Abstract]
Useful life	7 years
Computers and Equipment [Member] \| Minimum [Member]
Property and Equipment [Abstract]
Useful life	3 years
Computers and Equipment [Member] \| Maximum [Member]
Property and Equipment [Abstract]
Useful life	5 years
Leasehold Improvements [Member]
Property and Equipment [Abstract]
Estimated useful life description	Shorter of estimated useful life or lease term
Scanners [Member]
Property and Equipment [Abstract]
Useful life	3 years
Vehicles [Member] \| Minimum [Member]
Property and Equipment [Abstract]
Useful life	3 years
Vehicles [Member] \| Maximum [Member]
Property and Equipment [Abstract]
Useful life	5 years

Summary of Significant Accounting Policies, Revenue Recognition (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue Recognition [Abstract]
Sales returns	$ 53.8	$ 61.2	$ 65.6
Allowance for Product Returns [Member]
Revenue Recognition [Abstract]
Accrued reserve	$ 4.5	$ 6.1

Summary of Significant Accounting Policies, Advertising Expenses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Advertising Expense [Abstract]
Advertising costs incurred	$ 15.6	$ 15.9	$ 11.0

Summary of Significant Accounting Policies, Research and Development (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Research and Development [Abstract]
Research and development expense	$ 22.0	$ 24.3	$ 20.1

Summary of Significant Accounting Policies, Uncertain Tax Positions (Details) - Multiple Foreign and Domestic Authorities [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of Unrecognized Tax Benefits [Roll Forward]
Gross balance at beginning of year	$ 5,290	$ 7,772	$ 5,987
Increases related to prior year tax positions	0	185	1,677
Decrease related to prior year tax positions	(277)	0	0
Increases related to current year tax positions	669	918	1,119
Settlements	(159)	(3,369)	0
Decreases due to lapse of statutes of limitations	(187)	(252)	(667)
Currency adjustments			(344)
Currency adjustments	178	36
Gross balance at end of year	5,514	5,290	7,772
Uncertain Tax Positions [Abstract]
Unrecognized tax benefits that would impact effective tax rate	5,200	1,000
Interest and penalties expenses/(benefits)	700	(800)	400
Accrued interest and penalties	1,600	$ 900	$ 1,700
Minimum [Member]
Uncertain Tax Positions [Abstract]
Estimated increase in gross unrecognized tax benefits within next 12 months	2,500
Maximum [Member]
Uncertain Tax Positions [Abstract]
Estimated increase in gross unrecognized tax benefits within next 12 months	$ 3,500

Summary of Significant Accounting Policies, Foreign Currency Translation (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Foreign Currency Translation [Abstract]
Cumulative translation adjustment related to foreign currency adjustment	$ (66.4)	$ (84.7)	$ (71.6)
Cumulative translation adjustment related to foreign currency adjustment, tax	$ 5.8	$ 13.4	$ 10.9

Summary of Significant Accounting Policies, Classification of Venezuela as a Highly Inflationary Economy and Devaluation of Its Currency (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($)	Mar. 31, 2015 Bs. / $
Operations in Venezuela [Abstract]
Foreign currency transaction losses on net monetary assets denominated in bolivar	$ 10.2
Other Income (Expense), Net [Member]
Operations in Venezuela [Abstract]
Foreign currency transaction losses on net monetary assets denominated in bolivar	$ 10.2
Venezuela [Member]
Operations in Venezuela [Abstract]
Foreign currency exchange rate for SIMADI \| Bs. / $		193

Summary of Significant Accounting Policies, Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Fair Value of Financial Instruments [Abstract]
Long-term debt fair value	$ 515.2	$ 497.4

Summary of Significant Accounting Policies, Stock-Based Compensation (Details) - General and Administrative Expense [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Stock-Based Compensation [Abstract]
Compensation expense related to equity compensation plans	$ 19.3	$ 8.9	$ 7.4
Reversal of compensation expense for certain performance based awards no longer expected to vest	$ 0.0	$ 9.6	$ 7.6

Summary of Significant Accounting Policies, Recent Accounting Pronouncements (Details) - Accounting Standards Update 2016-09 [Member] $ in Thousands	Dec. 31, 2016 USD ($)
Accounting Pronouncements [Abstract]
Cumulative adjustment	$ 0
Retained Earnings [Member]
Accounting Pronouncements [Abstract]
Cumulative adjustment	(2,800)
Additional Paid-in Capital [Member]
Accounting Pronouncements [Abstract]
Cumulative adjustment	$ 2,800

Prepaid Expenses and Other (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Prepaid Expenses and Other [Abstract]
Deferred charges	$ 4,256	$ 9,319
Prepaid income taxes	0	6,799
Prepaid inventory and import costs	9,397	10,857
Prepaid rent, insurance and other occupancy costs	14,558	13,398
Prepaid promotion and event cost	3,581	4,126
Prepaid other taxes	5,559	4,778
Forward contracts	158	1,371
Deposits	1,147	1,079
Other	14,237	13,349
Total prepaid expenses and other	$ 52,893	$ 65,076

Property and Equipment (Details) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Less: accumulated depreciation

$ 750,826

$ 678,457

(286,239)

(233,725)

Property and equipment, net

464,587

444,732

$ 454,537

Depreciation expense

58,300

60,800

$ 61,600

Land [Member]

33,667

33,158

Buildings [Member]

Construction in Progress [Member]

274,632

266,436

Furniture and Fixtures [Member]

^[1]

53,125

31,124

Computers and Equipment [Member]

95,378

82,194

Leasehold Improvements [Member]

156,994

143,014

123,479

109,863

Scanners [Member]

11,212

10,578

Vehicles [Member]

Internal-Use Software Development Costs [Member]

2,339

2,090

$ 43,400

$ 25,800

[1]	Construction in progress includes $25.8 million and $[___] million as of December 31, 2016 and 2017, respectively, of eligible capitalized internal-use software development costs which will be reclassified to computers and equipment when placed into service.

Goodwill (Details)
$ in Thousands

12 Months Ended

Dec. 31, 2017

USD ($)

Segment

Dec. 31, 2016

USD ($)

^[1]

Number of segments | Segment

$ 114,954

Mainland China [Member]

32,179

South Korea [Member]

29,261

Americas [Member]

South Asia/Pacific [Member]

9,449

18,537

Japan [Member]

Hong Kong/Taiwan [Member]

16,019

6,634

EMEA [Member]

$ 2,875

[1]	Goodwill was recast to reflect current period presentation by geographic region at December 31, 2016.

Other Intangible Assets, Indefinite Life Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Indefinite Life Intangible Assets [Abstract]
Indefinite life intangible assets	$ 28,362	$ 28,362
Trademarks and Trade Names [Member]
Indefinite Life Intangible Assets [Abstract]
Indefinite life intangible assets	24,599	24,599
Other Indefinite Lived Intangibles [Member]
Indefinite Life Intangible Assets [Abstract]
Indefinite life intangible assets	$ 3,763	$ 3,763

Other Intangible Assets, Finite Life Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Finite Life Intangible Assets [Abstract]
Gross carrying amount	$ 140,915	$ 129,391
Accumulated amortization	$ 101,630	94,200
Weighted-average amortization period	15 years
Amortization expense	$ 8,100	8,400	$ 8,600
Write-off of fully amortized intangible assets		12,000
Scanner Technology [Member]
Finite Life Intangible Assets [Abstract]
Gross carrying amount	46,482	46,482
Accumulated amortization	$ 39,657	36,624
Weighted-average amortization period	18 years
Developed Technology [Member]
Finite Life Intangible Assets [Abstract]
Gross carrying amount	$ 22,500	22,500
Accumulated amortization	$ 19,207	18,383
Weighted-average amortization period	20 years
Distribution Network [Member]
Finite Life Intangible Assets [Abstract]
Gross carrying amount	$ 11,598	11,598
Accumulated amortization	$ 11,598	11,598
Weighted-average amortization period	15 years
Trademarks [Member]
Finite Life Intangible Assets [Abstract]
Gross carrying amount	$ 2,785	2,592
Accumulated amortization	$ 1,197	1,011
Weighted-average amortization period	15 years
Other [Member]
Finite Life Intangible Assets [Abstract]
Gross carrying amount	$ 57,550	46,219
Accumulated amortization	$ 29,971	$ 26,584
Weighted-average amortization period	8 years

Other Intangible Assets, Annual Estimated Future Amortization Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Annual Estimated Future Amortization Expense [Abstract]
2018	$ 8,978
2019	8,876
2020	4,898
2021	4,148
2022	5,201
Impairment Charges [Abstract]
Indefinite life intangible assets impairment charge	$ 0	$ 0	$ 0

Other Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other Assets [Abstract]
Deferred taxes	$ 33,785	$ 35,752
Deposits for noncancelable operating leases	43,375	38,858
Cash surrender value for life insurance policies	37,737	32,286
Other	49,998	29,573
Total other assets	$ 164,895	$ 136,469

Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accrued Expenses [Abstract]
Accrued sales force commissions and other payments	$ 151,549	$ 126,153
Accrued income taxes	13,075	0
Accrued other taxes	44,580	31,748
Accrued payroll and other employee expenses	38,167	25,412
Accrued payable to vendors	29,874	28,456
Accrued royalties	2,623	4,767
Sales return reserve	4,523	6,125
Deferred revenue	12,669	13,494
Other	22,129	38,868
Total accrued expenses	$ 319,189	$ 275,023

Other Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other Liabilities [Abstract]
Deferred tax liabilities	$ 36,718	$ 643
Reserve for other tax liabilities	7,163	6,264
Liability for deferred compensation plan	43,248	36,730
Pension plan benefits reserve	6,359	5,631
Build to suit - financing obligation	10,290	9,543
Deferred rent and deferred tenant incentives	6,389	5,952
Asset retirement obligation	6,578	5,682
Other	10,371	6,354
Total other liabilities	$ 127,116	$ 76,799

Long-Term Debt, Credit Agreement (Details)
$ in Thousands, ¥ in Billions

12 Months Ended

Dec. 31, 2017

USD ($)

Dec. 31, 2017

JPY (¥)

Dec. 31, 2016

USD ($)

Dec. 31, 2016

JPY (¥)

Oct. 09, 2014

USD ($)

Oct. 09, 2014

JPY (¥)

Credit Agreement [Member] | Maximum [Member]

^[1]

$ 401,768

Consolidated leverage ratio

2.25

Credit Agreement [Member] | Minimum [Member]

Consolidated interest coverage ratio

3.00

Term Loan Facility [Member]

$ 127,500

5 years

Japanese Yen Term Loan Facility [Member]

$ 94,800

^[2],[3]

$ 108,400

Original principal amount | ¥

¥ 6.6

5 years

Revolving Credit Facility [Member]

$ 43,500

^[2],[3]

¥ 4.9

^[2],[3]

47,900

¥ 5.6

Borrowing capacity

$ 187,500

5 years

Equity component of convertible notes allocated to additional paid-in capital

$ 47,500

^[2],[3]

$ 47,500

[1]	The carrying value of the debt reflects the amounts stated in the above table less a debt discount of $13.1 million, which is not reflected in this table.
[2]	As of December 31, 2017, the current portion of the Company's debt (i.e. becoming due in the next 12 months) included $16.7 million of the balance of its U.S. dollar denominated debt under the Credit Agreement facility, $7.7 million of the balance of its Japanese yen-denominated debt under the Credit Agreement facility and $5.9 million of the Japan subsidiary loan. The Company has classified the $47.5 million borrowed under the revolving line of credit as short term because it is the Company's intention to use the line of credit to borrow and pay back funds over short periods of time.
[3]	The carrying value of the debt reflects the amounts stated in the above table less a debt discount of $9.1 million and debt issuance costs of $4.0 million (consisting of $11.1 million related to the Convertible Note and $2.0 million related to the credit agreement), which is not reflected in this table.

Long-Term Debt, Convertible Note (Details)

12 Months Ended

Jun. 16, 2016

USD ($)

Dec. 31, 2017

USD ($)

$ / shares

Dec. 31, 2016

USD ($)

Dec. 31, 2015

USD ($)

Convertible Debt [Abstract]

$ 6,825,000

Net Carrying Amount of Liability Component [Abstract]

Principal

^[1]

$ 401,768,000

Unamortized debt discount (conversion option)

(9,100,000)

Unamortized debt discount (issuance costs)

(4,000,000)

Debt issuance costs

6,596,000

$ 0

Convertible Note [Member]

22,200,000

15,600,000

$ 7,900,000

Convertible Debt [Abstract]

$ 210,000,000

Redemption price, percentage of principal amount redeemed

4.75%

Maturity date

Jun. 15, 2020

100.00%

Threshold percentage of stock price trigger

180.00%

Threshold trading days | d

Threshold final trading days | d

Threshold consecutive trading days | d

Principal amount increments that can be repurchased upon a change in control or termination of trading of common stock

$ 1,000

Principal amount increments that can be converted

$ 1,000

Holding period following issue date before notes can be converted

6 months

Initial conversion rate (in shares) | shares

21.5054

Initial conversion price (in dollars per share) | $ / shares

$ 46.50

Proceeds from issuance of notes

210,000,000

Liability component of convertible notes

199,100,000

Equity component of convertible notes allocated to additional paid-in capital

$ 10,900,000

Effective interest rate

7.10%

Net Carrying Amount of Liability Component [Abstract]

Principal

$ 210,000,000

Unamortized debt discount (conversion option)

(7,078,000)

Total long-term debt, net

202,922,000

Unamortized debt discount (issuance costs)

(4,050,000)

Net carrying amount

198,872,000

Debt issuance costs

6,596,000

Additions to deferred financing cost

6,300,000

Adjustments to additional paid-in capital for debt issuance costs

300,000

Amortization of debt issuance costs and debt discount

14,000,000

Contractual interest

10,000,000

$ 4,000,000

[1]	The carrying value of the debt reflects the amounts stated in the above table less a debt discount of $13.1 million, which is not reflected in this table.

Long-Term Debt, Debt Facilities (Details)
$ in Thousands, ¥ in Billions

12 Months Ended

Dec. 31, 2017

USD ($)

Dec. 31, 2016

USD ($)

Dec. 31, 2015

USD ($)

Dec. 31, 2017

JPY (¥)

Dec. 31, 2016

JPY (¥)

Jun. 16, 2016

USD ($)

Oct. 09, 2014

USD ($)

Oct. 09, 2014

JPY (¥)

^[1]

$ 401,768

Unamortized debt discount

77,840

$ 82,727

9,100

Unamortized debt issuance costs

4,000

13,100

Credit Agreement [Member]

22,200

15,600

$ 7,900

Term Loan Facility [Member]

2,000

127,500

$ 127,500

$ 94,800

^[2],[3]

108,400

Variable 30 day: 4.319%

4.319%

Term of variable rate

30 days

Percentage of principal payable in installments

One half of the principal amount payable in increasing quarterly installments over a five-year period beginning on December 31, 2014, with the remainder payable at the end of the five-year term.

50.00%

Frequency of payment

Quarterly

5 years

Japanese Yen Term Loan Facility [Member]

$ 16,700

Original principal amount | ¥

¥ 6.6

$ 43,500

^[2],[3]

47,900

¥ 4.9

^[2],[3]

¥ 5.6

Variable 30 day: 2.75%

2.75%

Term of variable rate

30 days

Percentage of principal payable in installments

One half of the principal amount payable in increasing quarterly installments over a five-year period beginning on December 31, 2014, with the remainder payable at the end of the five-year term.

50.00%

Frequency of payment

Quarterly

5 years

Revolving Credit Facility [Member]

$ 7,700

$ 47,500

^[2],[3]

47,500

Variable 30 day: 4.319%

4.319%

Term of variable rate

30 days

Revolving line of credit expires October 2019.

South Korea Subsidiary Loan [Member]

5 years

$ 20,000

$ 0

^[2],[3]

10,000

1.12%

Japan Subsidiary Loan [Member]

Loan was paid off in March 2017.

Original principal amount | ¥

¥ 2.0

$ 5,900

^[2],[3]

11,400

¥ 0.7

^[2],[3]

¥ 1.3

0.66%

Payable in semi-annual installments over three years that began on January 31, 2016.

Frequency of payment

Semi-annual

3 years

Convertible Note [Member]

$ 5,900

Unamortized debt discount

210,000

$ 210,000

$ 210,000

7.10%

4.75%

Principal amount payable on June 15, 2020.

$ 7,078

Unamortized debt issuance costs

4,050

11,100

Maturities of Long-term Debt [Abstract]

$ 14,000

[1]	The carrying value of the debt reflects the amounts stated in the above table less a debt discount of $13.1 million, which is not reflected in this table.
[2]	As of December 31, 2017, the current portion of the Company's debt (i.e. becoming due in the next 12 months) included $16.7 million of the balance of its U.S. dollar denominated debt under the Credit Agreement facility, $7.7 million of the balance of its Japanese yen-denominated debt under the Credit Agreement facility and $5.9 million of the Japan subsidiary loan. The Company has classified the $47.5 million borrowed under the revolving line of credit as short term because it is the Company's intention to use the line of credit to borrow and pay back funds over short periods of time.
[3]	The carrying value of the debt reflects the amounts stated in the above table less a debt discount of $9.1 million and debt issuance costs of $4.0 million (consisting of $11.1 million related to the Convertible Note and $2.0 million related to the credit agreement), which is not reflected in this table.

Long-Term Debt, Maturities of Long-Term Debt (Details)
$ in Thousands

Dec. 31, 2017

USD ($)

$ 77,840

113,928

210,000

401,768

^[1]

Weighted average grant date fair value of grants (in dollars per share)

$ 13,100

[1]	The carrying value of the debt reflects the amounts stated in the above table less a debt discount of $13.1 million, which is not reflected in this table.

Lease and Financing Obligations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
New Building [Abstract]
Value of New Building	$ 750,826	$ 678,457
Accumulated depreciation	286,239	233,725
Deposit paid to landlord	43,375	38,858
Operating Leases, Minimum Future Obligations [Abstract]
2018	41,788
2019	27,088
2020	14,907
2021	10,036
2022	7,672
Thereafter	13,250
Total	114,741
Financing Obligations, Minimum Future Obligations [Abstract]
2018	736
2019	758
2020	781
2021	790
2022	804
Thereafter	2,027
Total minimum lease payments	5,896
Rent expense for operating leases	50,700	48,200	$ 52,400
Interest expense associated with financing obligation	$ 200	200	$ 100
New Regional Headquarters Building [Member]
New Building [Abstract]
Extension period for lease	10 years
Initial term of lease	10 years
Value of New Building	$ 20,800	18,900
Accumulated depreciation	1,500	800
Financing obligation	10,800	10,000
Deposit paid to landlord	10,300	9,100
Tenant incentive asset	4,900	4,900
Deferred tenant incentive liability	$ 4,500	$ 4,500
Office Space and Computer Hardware [Member]
New Building [Abstract]
Extension period for lease	3 years

Capital Stock (Details) $ / shares in Units, $ in Thousands	12 Months Ended
Capital Stock (Details) $ / shares in Units, $ in Thousands	Dec. 31, 2017 USD ($) Vote $ / shares shares	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) shares	Oct. 31, 2015 USD ($)	Aug. 31, 2013 USD ($)	Dec. 31, 1998 USD ($)
Capital Stock [Abstract]
Preferred stock, authorized (in shares)	25,000,000
Preferred stock, par value (in dollars per share) \| $ / shares	$ 0.001
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, par value (in dollars per share) \| $ / shares	$ 0.001	$ 0.001
Preferred stock, shares outstanding (in shares)	0	0
Weighted Average Shares Outstanding [Abstract]
Basic weighted-average common shares outstanding (in shares)	52,806,000	55,412,000	57,997,000
Effect of Dilutive Securities [Abstract]
Stock awards and options (in shares)	1,110,000	683,000	1,060,000
Convertible note (in shares)	936,000	2,000	0
Diluted weighted-average common shares outstanding (in shares)	54,852,000	56,097,000	59,057,000
Repurchases of Common Stock [Abstract]
Repurchase of Class A common stock \| $	$ 71,731	$ 247,208	$ 164,094
Amount available for repurchases \| $	$ 128,000
Stock Options [Member]
Effect of Dilutive Securities [Abstract]
Anti-dilutive shares excluded from calculation of diluted earnings per share (in shares)	400,000	2,000,000	1,800,000
Common Class A [Member]
Capital Stock [Abstract]
Common stock, shares authorized (in shares)	500,000,000
Common stock, par value (in dollars per share) \| $ / shares	$ 0.001
Number of votes per share \| Vote	1
Number of shares of class A common stock issued after conversion of Class B common stock (in shares)	1
Repurchases of Common Stock [Abstract]
Shares repurchased (in shares)	1,200,000	4,500,000	3,800,000
Authorized amount \| $				$ 500,000		$ 10,000
Increase in authorized amount \| $					$ 400,000
Common Class B [Member]
Capital Stock [Abstract]
Common stock, shares authorized (in shares)	100,000,000
Common stock, par value (in dollars per share) \| $ / shares	$ 0.001
Common stock, shares outstanding (in shares)	0	0
Number of votes per share \| Vote	10
Treasury Stock [Member]
Repurchases of Common Stock [Abstract]
Repurchase of Class A common stock \| $	$ 71,731	$ 247,208	$ 164,094

Stock-Based Compensation, Equity Incentive Plans (Details) shares in Millions			12 Months Ended
	May 24, 2016 shares	Jun. 03, 2013 shares	Dec. 31, 2017 Installment Level	Apr. 30, 2010 shares
2010 Omnibus Incentive Plan [Member]
Stock-Based Compensation [Abstract]
Number of shares authorized for issuance (in shares)				7.0
2010 Omnibus Incentive Plan [Member] \| Stock Options [Member] \| Minimum [Member]
Stock-Based Compensation [Abstract]
Contractual term of stock options granted			7 years
2010 Omnibus Incentive Plan [Member] \| Stock Options [Member] \| Maximum [Member]
Stock-Based Compensation [Abstract]
Contractual term of stock options granted			10 years
Amended and Restated 2010 Omnibus Incentive Plan [Member]
Stock-Based Compensation [Abstract]
Number of additional shares authorized for issuance (in shares)		3.2
Amended and Restated 2010 Omnibus Incentive Plan [Member] \| Performance-Based Options [Member]
Stock-Based Compensation [Abstract]
Number of installments for vesting \| Installment			4
Number of established performance levels for vesting \| Level			4
Amended and Restated 2010 Omnibus Incentive Plan [Member] \| Performance-Based Options [Member] \| First Performance Level [Member]
Stock-Based Compensation [Abstract]
Vesting percentage			25.00%
Amended and Restated 2010 Omnibus Incentive Plan [Member] \| Performance-Based Options [Member] \| Second Performance Level [Member]
Stock-Based Compensation [Abstract]
Vesting percentage			25.00%
Amended and Restated 2010 Omnibus Incentive Plan [Member] \| Performance-Based Options [Member] \| Third Performance Level [Member]
Stock-Based Compensation [Abstract]
Vesting percentage			25.00%
Amended and Restated 2010 Omnibus Incentive Plan [Member] \| Performance-Based Options [Member] \| Fourth Performance Level [Member]
Stock-Based Compensation [Abstract]
Vesting percentage			25.00%
Second Amended and Restated 2010 Omnibus Incentive Plan [Member]
Stock-Based Compensation [Abstract]
Number of additional shares authorized for issuance (in shares)	3.8

Stock-Based Compensation, Stock Option Valuation Assumptions (Details) - Stock Options [Member] - $ / shares

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Fair Value Assumptions [Abstract]

$ 18.84

$ 12.59

$ 16.26

Risk-free interest rate

^[1]

2.10%

1.40%

1.70%

Dividend yield

^[2]

2.50%

2.30%

2.10%

Expected volatility

^[3]

48.20%

47.90%

46.80%

Expected life in months

^[4]

68 months

65 months

[1]	The risk-free interest rate is based upon the rate on a zero coupon U.S. Treasury bill, for periods within the contractual life of the option, in effect at the time of the grant.
[2]	The dividend yield is based on the average of historical stock prices and actual dividends paid.
[3]	Expected volatility is based on the historical volatility of the Company's stock price, over a period similar to the expected life of the option.
[4]	The expected term of the option is based on the historical employee exercise behavior, the vesting terms of the respective option, and a contractual life of either seven or ten years.

Stock-Based Compensation, Stock Options (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) $ / shares shares
Stock Options [Member]
Number of Shares [Roll Forward]
Outstanding at beginning of year (in shares) \| shares	5,932,900
Granted (in shares) \| shares	298,000
Exercised (in shares) \| shares	(1,177,400)
Forfeited/cancelled/expired (in shares) \| shares	(1,359,100)
Outstanding at end of year (in shares) \| shares	3,694,400
Exercisable at end of year (in shares) \| shares	1,019,600
Weighted-Average Exercise Price [Roll Forward]
Outstanding at beginning of year (in dollars per share) \| $ / shares	$ 51.42
Granted (in dollars per share) \| $ / shares	50.93
Exercised (in dollars per share) \| $ / shares	31.92
Forfeited/cancelled/expired (in dollars per share) \| $ / shares	60.69
Outstanding at end of year (in dollars per share) \| $ / shares	54.17
Exercisable at end of year (in dollars per share) \| $ / shares	$ 40.96
Remaining Contractual Term and Aggregate Intrinsic Value [Abstract]
Outstanding options, weighted-average remaining contractual term	3 years 10 months 24 days
Outstanding options, aggregate intrinsic value \| $	$ 67,962
Exercisable options, weighted-average remaining contractual term	3 years 8 months 23 days
Exercisable options, aggregate intrinsic value \| $	$ 29,838
Service-Based Options [Member]
Number of Shares [Roll Forward]
Outstanding at beginning of year (in shares) \| shares	2,207,000
Granted (in shares) \| shares	0
Exercised (in shares) \| shares	(324,400)
Forfeited/cancelled/expired (in shares) \| shares	(489,700)
Outstanding at end of year (in shares) \| shares	1,392,900
Exercisable at end of year (in shares) \| shares	725,500
Weighted-Average Exercise Price [Roll Forward]
Outstanding at beginning of year (in dollars per share) \| $ / shares	$ 39.93
Granted (in dollars per share) \| $ / shares	0
Exercised (in dollars per share) \| $ / shares	34.71
Forfeited/cancelled/expired (in dollars per share) \| $ / shares	43.85
Outstanding at end of year (in dollars per share) \| $ / shares	39.76
Exercisable at end of year (in dollars per share) \| $ / shares	$ 43.14
Remaining Contractual Term and Aggregate Intrinsic Value [Abstract]
Outstanding options, weighted-average remaining contractual term	4 years 4 months 10 days
Outstanding options, aggregate intrinsic value \| $	$ 41,756
Exercisable options, weighted-average remaining contractual term	3 years 6 months 18 days
Exercisable options, aggregate intrinsic value \| $	$ 20,237
Performance-Based Options [Member]
Number of Shares [Roll Forward]
Outstanding at beginning of year (in shares) \| shares	3,725,900
Granted (in shares) \| shares	298,000
Exercised (in shares) \| shares	(853,000)
Forfeited/cancelled/expired (in shares) \| shares	(869,400)
Outstanding at end of year (in shares) \| shares	2,301,500
Exercisable at end of year (in shares) \| shares	294,100
Weighted-Average Exercise Price [Roll Forward]
Outstanding at beginning of year (in dollars per share) \| $ / shares	$ 58.23
Granted (in dollars per share) \| $ / shares	50.93
Exercised (in dollars per share) \| $ / shares	30.86
Forfeited/cancelled/expired (in dollars per share) \| $ / shares	70.17
Outstanding at end of year (in dollars per share) \| $ / shares	62.89
Exercisable at end of year (in dollars per share) \| $ / shares	$ 35.58
Remaining Contractual Term and Aggregate Intrinsic Value [Abstract]
Outstanding options, weighted-average remaining contractual term	3 years 7 months 10 days
Outstanding options, aggregate intrinsic value \| $	$ 26,206
Exercisable options, weighted-average remaining contractual term	4 years 2 months 1 day
Exercisable options, aggregate intrinsic value \| $	$ 9,601

Stock-Based Compensation, Stock Options Exercised (Details) - Stock Options [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Stock-Based Compensation [Abstract]
Cash proceeds from stock options exercised	$ 26,980	$ 15,707	$ 13,041
Tax benefit realized for stock options exercised	6,457	3,840	4,451
Intrinsic value of stock options exercised	$ 42,749	$ 30,587	$ 12,085

Stock-Based Compensation, Nonvested Restricted Stock Awards (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Stock-Based Compensation Expense [Abstract]
Stock-based compensation expense (income)	$ 19,314	$ 8,890	$ 7,400
Stock Options [Member]
Weighted-Average Grant Date Fair Value [Abstract]
Granted (in dollars per share)	$ 50.93
Unrecognized Stock-Based Compensation Expense [Abstract]
Unrecognized stock-based compensation expense	$ 6,400
Unrecognized stock-based compensation expense, period for recognition	1 year 10 months 24 days
Restricted Stock Awards [Member]
Number of Shares [Roll Forward]
Nonvested at beginning of year (in shares)	596,400
Granted (in shares)	261,600
Vested (in shares)	(203,200)
Forfeited (in shares)	(91,900)
Nonvested at end of year (in shares)	562,900	596,400
Weighted-Average Grant Date Fair Value [Abstract]
Nonvested, beginning balance (in dollars per share)	$ 53.62
Granted (in dollars per share)	50.95
Vested (in dollars per share)	53.94
Forfeited (in dollars per share)	60.30
Nonvested, Ending Balance (in dollars per share)	$ 51.17	$ 53.62
Unrecognized Stock-Based Compensation Expense [Abstract]
Unrecognized stock-based compensation expense	$ 16,300
Unrecognized stock-based compensation expense, period for recognition	2 years 4 months 24 days
Service-Based Options [Member]
Weighted-Average Grant Date Fair Value [Abstract]
Granted (in dollars per share)	$ 0
Stock-Based Compensation Expense [Abstract]
Stock-based compensation expense (income)	$ 4,000	$ 5,800	2,600
Service-Based Restricted Stock Units [Member]
Stock-Based Compensation Expense [Abstract]
Stock-based compensation expense (income)	$ 11,300	10,500	10,900
Performance-Based Options [Member]
Weighted-Average Grant Date Fair Value [Abstract]
Granted (in dollars per share)	$ 50.93
Stock-Based Compensation Expense [Abstract]
Stock-based compensation expense (income)	$ 3,900	(7,100)	(6,500)
Performance Stock Units [Member]
Stock-Based Compensation Expense [Abstract]
Stock-based compensation expense (income)	$ 100	$ (300)	$ 400

Fair Value (Details) - USD ($) $ in Thousands	12 Months Ended
Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value on a Recurring Basis [Member]
Financial Assets (Liabilities) [Abstract]
Cash equivalents and current investments	$ 36,531	$ 50,307
Other long-term assets	3,726	2,782
Forward contracts	158	1,371
Life insurance contracts	37,737	32,286
Financial assets (liabilities), net	78,152	86,746
Restricted current investments	11,800	10,900
Fair Value on a Recurring Basis [Member] \| Level 1 [Member]
Financial Assets (Liabilities) [Abstract]
Cash equivalents and current investments	36,531	50,307
Other long-term assets	3,726	2,782
Forward contracts	0	0
Life insurance contracts	0	0
Financial assets (liabilities), net	40,257	53,089
Fair Value on a Recurring Basis [Member] \| Level 2 [Member]
Financial Assets (Liabilities) [Abstract]
Cash equivalents and current investments	0	0
Other long-term assets	0	0
Forward contracts	158	1,371
Life insurance contracts	0	0
Financial assets (liabilities), net	158	1,371
Fair Value on a Recurring Basis [Member] \| Level 3 [Member]
Financial Assets (Liabilities) [Abstract]
Cash equivalents and current investments	0	0
Other long-term assets	0	0
Forward contracts	0	0
Life insurance contracts	37,737	32,286
Financial assets (liabilities), net	37,737	32,286
Insurance Company Contracts [Member]
Changes in Fair Value of Level 3 Marketable Securities [Roll Forward]
Beginning balance	32,287	27,292
Actual Return on Plan Assets [Abstract]
Relating to assets still held at the reporting date	4,917	2,196
Purchases and issuances	895	3,051
Sales and settlements	(362)	(252)
Transfers into Level 3	0	0
Ending balance	$ 37,737	$ 32,287

Income Taxes, Tax Cuts and Jobs Act (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Tax Cuts and Jobs Act of 2017 [Abstract]
Corporate income tax rate			35.00%	35.00%	35.00%
Charge to deferred income tax expense for effects of Tax Reform Act	$ 47.7
Recognition of valuation allowance on foreign tax credit carryforwards	52.0
Charge to deferred income tax expense related to reversal of indefinite reinvestment assertion	7.3
Charge to deferred income tax expense related to reduction in FIN 48 assets	4.1
Benefit related to write-off of net outside basis deferred tax liabilities	(7.7)
Benefit related to tax effect on OCI	(3.1)
Benefit related to estimated impact of remeasurement of deferred tax assets and liabilities	(4.9)
Estimated Toll Charge	$ 96.0
Plan [Member]
Tax Cuts and Jobs Act of 2017 [Abstract]
Corporate income tax rate		21.00%

Income Taxes, Consolidated Income Before Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Consolidated Income Before Provision for Income Taxes [Abstract]
U.S.	$ 1,135	$ (19,119)	$ 134,473
Foreign	264,432	231,958	77,486
Income before provision for income taxes	$ 265,567	$ 212,839	$ 211,959

Income Taxes, Current and Deferred Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current [Abstract]
Federal	$ (14,358)	$ 0	$ 6,328
State	1,814	(718)	1,483
Foreign	104,688	70,652	50,403
Current income tax expense (benefit)	92,144	69,934	58,214
Deferred [Abstract]
Federal	45,593	(27,171)	16,556
State	(2,273)	1,104	(674)
Foreign	666	25,886	4,817
Deferred income tax expense (benefit)	43,986	(181)	20,699
Provision for income taxes	$ 136,130	$ 69,753	$ 78,913

Income Taxes, Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Deferred Tax Assets [Abstract]
Inventory differences	$ 2,861	$ 2,521
Foreign tax credit and other foreign benefits	52,408	145,169
Stock-based compensation	6,327	11,470
Accrued expenses not deductible until paid	39,326	32,796
Foreign currency exchange	2,001	4,826
Net operating losses	5,230	9,584
Capitalized research and development	197	358
Other	211	1,063
Gross deferred tax assets	108,561	207,787
Deferred Tax Liabilities [Abstract]
Foreign currency exchange	874	105
Foreign withholding taxes	29,018	0
Intangibles step-up	6,568	12,107
Overhead allocation to inventory	3,977	4,820
Amortization of intangibles	11,475	19,091
Foreign outside basis in controlled foreign corporation	0	106,846
Other	2,676	20,572
Gross deferred tax liabilities	54,588	163,541
Valuation allowance	(56,906)	(9,137)
Deferred taxes, net		$ 35,109
Deferred taxes, net	(2,933)
Foreign [Member]
Operating Loss Carryforwards [Abstract]
Operating loss carryforwards	17,100
Operating loss carryforwards scheduled to expire	5,700
Operating loss carryforwards that will not expire	11,400
Valuation allowance on operating loss carryforwards	15,900
Tax Credit Carryforwards [Abstract]
Tax credit carryforward	$ 52,000
Foreign [Member] \| Minimum [Member]
Operating Loss Carryforwards [Abstract]
Expiration date	Dec. 31, 2018
Tax Credit Carryforwards [Abstract]
Expiration date	Dec. 31, 2026
Foreign [Member] \| Maximum [Member]
Operating Loss Carryforwards [Abstract]
Expiration date	Dec. 31, 2027
Tax Credit Carryforwards [Abstract]
Expiration date	Dec. 31, 2027

Income Taxes, Deferred Tax Asset Valuation Adjustments (Details) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Valuation Allowance [Roll Forward]

Recognition of valuation allowance on foreign tax credit carryforwards

$ 52,000

Deferred Tax Asset Valuation Allowance [Member]

Valuation Allowance [Roll Forward]

Beginning balance

$ 9,137

$ 49,271

^[1]

$ 35,999

Additions charged to cost and expenses

53,983

^[2]

692

12,948

Decreases

(6,400)

^[3]

(40,442)

^[4]

(2,943)

^[5]

Adjustments

^[6]

186

(384)

3,267

Ending balance

$ 56,906

$ 9,137

$ 49,271

^[1]

[1]	The increase was due primarily to the deferred tax assets created by the unrealized loss in Venezuela for which the Company set up a full valuation allowance.
[2]	Increase in valuation is due primarily to the $52.0 million that was recorded on the foreign tax credit carryforward. The additional amount is due to net operating losses in foreign markets.
[3]	Decrease is due primarily to the write-off of Brazil deferred tax assets, which had no impact to the income statement, as a valuation allowance had been previously recorded against the asset.
[4]	Decrease in valuation allowance due to lapse in statute of limitation of the net operating losses carryforward and due to the write off of Venezuelan deferred tax assets, which had no impact to the income statement.
[5]	Decreases in valuation allowance due to lapse in statute of limitation of the net operating losses carryforward which had no impact to the income statement.
[6]	Represents the net currency effects of translating valuation allowances at current rates of exchange.

Income Taxes, Components of Deferred Taxes, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Income Taxes [Abstract]
Net noncurrent deferred tax assets	$ 33,785	$ 35,752
Net noncurrent deferred tax liabilities	36,718	643
Deferred taxes, net		$ 35,109
Deferred taxes, net	$ (2,933)

Income Taxes, Reconciliation of Statutory to Effective Tax Rate (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Effective income tax rate, continuing operations, tax rate reconciliation [Abstract]
Income taxes at statutory rate	35.00%	35.00%	35.00%
Indefinite reinvestment	2.75%	(1.98%)	0.92%
Excess tax benefit from equity award	(2.38%)	0.00%	0.00%
Non-deductible expenses	0.17%	0.11%	0.09%
Controlled foreign corporation losses	(0.13%)	(2.63%)	1.09%
Valuation allowance recognized foreign tax credit	19.59%	0.00%	0.00%
Write-off outside basis DTL	(2.89%)	0.00%	0.00%
Revaluation of deferred taxes	(1.28%)	0.00%	0.00%
Section 987 implementation	0.00%	2.69%	0.00%
Other	0.43%	(0.42%)	0.13%
Effective income tax rate, continuing operations	51.26%	32.77%	37.23%

Employee Benefit Plan (Details) - USD ($) $ in Millions	12 Months Ended
Employee Benefit Plan (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
401(k) Defined Contribution Plan [Member]
401(k) Defined Contribution Plan [Abstract]
Maximum percentage of compensation that can be deferred	100.00%
Minimum age to make contributions	18 years
Requisite service period	1 day
Percent of employees' base pay matched by employer	4.00%	4.00%	4.00%
Vesting period for Company's matching contributions	2 years
Compensation expense	$ 3.2	$ 2.8	$ 2.8
Additional discretionary contribution by employer, maximum percentage of employees' base pay	10.00%
Additional discretionary contribution by employer, annual vesting percentage	20.00%
Vesting period for Company's additional discretionary contributions	5 years
Defined Benefit Pension Plan [Member] \| Japan [Member]
Defined Benefit Pension Plan [Abstract]
Accrued pension liability	$ 6.1	5.6	4.8
Pension expense	$ 0.7	$ 0.9	$ 0.7

Executive Deferred Compensation Plan (Details) - Executive [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Executive Deferred Compensation Plan [Abstract]
Percentage of matching contribution maximum	10.00%
Percentage of compensation deferred, maximum	80.00%
Percentage of bonus deferred, maximum	100.00%
Percentage vested after ten years of service	50.00%
Number of years of service to attain fifty percent vesting	10 years
Percentage vested per year after ten years of service	5.00%
Minimum age for unvested company contributions to fully vest	60 years
Compensation expense	$ 1.5	$ 1.5	$ 2.3
Long-term deferred compensation liability	43.2	36.7
Investment in Rabbi Trust	$ 37.7	$ 32.3

Derivative Financial Instruments (Details) $ in Thousands, ₩ in Millions, ¥ in Billions	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2017 JPY (¥)	Dec. 31, 2017 KRW (₩)	Dec. 31, 2016 JPY (¥)	Dec. 31, 2016 KRW (₩)
Foreign Currency Derivatives [Abstract]
Unrealized gains/(losses) related to foreign currency cash flow hedges included in accumulated other comprehensive loss	$ 100	$ 600
Cumulative translation adjustments included in accumulated other comprehensive loss	(66,400)	(84,700)	$ (71,600)
Foreign Currency Forward Contracts [Member] \| Not Designated as Hedging Instrument [Member] \| Fair Value Hedges [Member]
Foreign Currency Derivatives [Abstract]
Fair value	0	500
Foreign Currency Forward Contracts [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedges [Member]
Foreign Currency Derivatives [Abstract]
Fair value	$ 200	900
Term to recognize gains (losses) in current earnings	6 months
Foreign Currency Forward Contracts [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedges [Member] \| Japanese Yen [Member]
Foreign Currency Derivatives [Abstract]
Notional amount	$ 5,500	12,000		¥ 0.6		¥ 1.4
Foreign Currency Forward Contracts [Member] \| Other Comprehensive Loss [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedges [Member]
Foreign Currency Derivatives [Abstract]
Gain (loss) recognized in other comprehensive income loss	(152)	(1,423)	590
Foreign Currency Forward Contracts [Member] \| Other Income (Expense) [Member] \| Not Designated as Hedging Instrument [Member] \| Korean Won [Member]
Foreign Currency Derivatives [Abstract]
Notional amount	0	9,500			₩ 0		₩ 11,500
Foreign Currency Forward Contracts [Member] \| Other Income (Expense) [Member] \| Not Designated as Hedging Instrument [Member] \| Fair Value Hedges [Member]
Foreign Currency Derivatives [Abstract]
Gain (loss) recognized in income	(485)	39	38
Foreign Currency Forward Contracts [Member] \| Revenue [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedges [Member]
Foreign Currency Derivatives [Abstract]
Gain (loss) reclassified from accumulated other comprehensive loss into income	119	(1,088)	1,731
Foreign Currency Forward Contracts [Member] \| Selling Expenses [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedges [Member]
Foreign Currency Derivatives [Abstract]
Gain (loss) reclassified from accumulated other comprehensive loss into income	$ 358	$ (1,544)	$ 397

Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Supplemental Cash Flow Information [Abstract]
Cash paid for interest	$ 18.4	$ 11.6	$ 7.0
Cash paid for income taxes	$ 78.1	$ 40.9	$ 49.8

Segment Information, Revenue by Segment (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) Segment Market	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Segment Information [Abstract]
Number of markets \| Market	50
Number of segments \| Segment	7
Revenue by Segment [Abstract]
Revenue	$ 2,279,099	$ 2,207,797	$ 2,247,047
Operating Segment [Member]
Revenue by Segment [Abstract]
Revenue	2,279,099	2,207,797	2,247,047
Operating Segment [Member] \| Mainland China [Member]
Revenue by Segment [Abstract]
Revenue	716,991	610,414	565,527
Operating Segment [Member] \| South Korea [Member]
Revenue by Segment [Abstract]
Revenue	361,692	413,696	422,341
Operating Segment [Member] \| Americas [Member]
Revenue by Segment [Abstract]
Revenue	317,380	276,590	329,668
Operating Segment [Member] \| South Asia/Pacific [Member]
Revenue by Segment [Abstract]
Revenue	299,980	296,758	321,971
Operating Segment [Member] \| Japan [Member]
Revenue by Segment [Abstract]
Revenue	256,085	279,042	264,214
Operating Segment [Member] \| Hong Kong/Taiwan [Member]
Revenue by Segment [Abstract]
Revenue	166,696	183,979	206,140
Operating Segment [Member] \| EMEA [Member]
Revenue by Segment [Abstract]
Revenue	$ 160,275	$ 147,318	$ 137,186

Segment Information, Segment Contribution (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Contribution [Abstract]
Operating income	$ 274,483	$ 231,104	$ 244,702
Other income (expense)	(8,916)	(18,265)	(32,743)
Income before provision for income taxes	265,567	212,839	211,959
Operating Segment [Member]
Segment Contribution [Abstract]
Operating income	518,849	473,610	438,895
Operating Segment [Member] \| Mainland China [Member]
Segment Contribution [Abstract]
Operating income	211,625	135,174	73,422
Operating Segment [Member] \| South Korea [Member]
Segment Contribution [Abstract]
Operating income	100,964	117,142	130,516
Operating Segment [Member] \| Americas [Member]
Segment Contribution [Abstract]
Operating income	47,040	44,390	62,937
Operating Segment [Member] \| South Asia/Pacific [Member]
Segment Contribution [Abstract]
Operating income	68,141	71,365	68,949
Operating Segment [Member] \| Japan [Member]
Segment Contribution [Abstract]
Operating income	51,372	59,175	51,181
Operating Segment [Member] \| Hong Kong/Taiwan [Member]
Segment Contribution [Abstract]
Operating income	27,958	35,978	40,718
Operating Segment [Member] \| EMEA [Member]
Segment Contribution [Abstract]
Operating income	11,749	10,386	11,172
Corporate and Other [Member]
Segment Contribution [Abstract]
Operating income	$ (244,366)	$ (242,506)	$ (194,193)

Segment Information, Depreciation and Amortization and Capital Expenditures (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Summarized Financial Information [Abstract]
Depreciation and amortization	$ 71,564	$ 72,397	$ 71,365
Capital expenditures	60,156	50,221	56,622
Reportable Geographic Region [Member] \| Mainland China [Member]
Summarized Financial Information [Abstract]
Depreciation and amortization	15,122	16,775	18,503
Capital expenditures	4,539	13,656	21,998
Reportable Geographic Region [Member] \| South Korea [Member]
Summarized Financial Information [Abstract]
Depreciation and amortization	6,499	6,787	5,882
Capital expenditures	469	556	9,983
Reportable Geographic Region [Member] \| Americas [Member]
Summarized Financial Information [Abstract]
Depreciation and amortization	1,608	2,617	2,545
Capital expenditures	744	1,095	400
Reportable Geographic Region [Member] \| South Asia/Pacific [Member]
Summarized Financial Information [Abstract]
Depreciation and amortization	2,372	2,388	2,022
Capital expenditures	1,809	2,282	2,959
Reportable Geographic Region [Member] \| Japan [Member]
Summarized Financial Information [Abstract]
Depreciation and amortization	3,554	3,782	3,434
Capital expenditures	994	1,288	1,903
Reportable Geographic Region [Member] \| Hong Kong/Taiwan [Member]
Summarized Financial Information [Abstract]
Depreciation and amortization	1,395	2,507	2,132
Capital expenditures	1,350	634	1,345
Reportable Geographic Region [Member] \| EMEA [Member]
Summarized Financial Information [Abstract]
Depreciation and amortization	985	1,387	1,498
Capital expenditures	1,168	1,224	1,430
Corporate and Other [Member]
Summarized Financial Information [Abstract]
Depreciation and amortization	40,029	36,154	35,349
Capital expenditures	$ 49,083	$ 29,486	$ 16,604

Segment Information, Revenue by Major Market (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) Market	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Segment Information [Abstract]
Number of major markets \| Market	3
Number of markets \| Market	50
Segment Contribution [Abstract]
Revenue	$ 2,279,099	$ 2,207,797	$ 2,247,047
United States [Member]
Segment Contribution [Abstract]
Revenue	218,734	201,239	243,748
All Others [Member]
Segment Contribution [Abstract]
Revenue	725,597	703,406	751,217
Major Market [Member] \| Mainland China [Member]
Segment Contribution [Abstract]
Revenue	716,991	610,414	565,527
Major Market [Member] \| South Korea [Member]
Segment Contribution [Abstract]
Revenue	361,692	413,696	422,341
Major Market [Member] \| Japan [Member]
Segment Contribution [Abstract]
Revenue	$ 256,085	$ 279,042	$ 264,214

Segment Information, Revenue by Product Line (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue by Product Line [Abstract]
Revenue	$ 2,279,099	$ 2,207,797	$ 2,247,047
Nu Skin [Member]
Revenue by Product Line [Abstract]
Revenue	1,456,386	1,308,135	1,363,539
Pharmanex [Member]
Revenue by Product Line [Abstract]
Revenue	817,230	892,738	877,924
Other [Member]
Revenue by Product Line [Abstract]
Revenue	$ 5,483	$ 6,924	$ 5,584

Segment Information, Long Lived Assets by Major Market (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Long-Lived Assets by Major Market [Abstract]
Long-lived assets	$ 464,587	$ 444,732	$ 454,537
Major Markets [Member] \| United States [Member]
Long-Lived Assets by Major Market [Abstract]
Long-lived assets	302,884	283,868	271,058
Major Markets [Member] \| Mainland China [Member]
Long-Lived Assets by Major Market [Abstract]
Long-lived assets	97,046	97,867	110,839
Major Markets [Member] \| South Korea [Member]
Long-Lived Assets by Major Market [Abstract]
Long-lived assets	42,211	41,545	48,702
Major Markets [Member] \| Japan [Member]
Long-Lived Assets by Major Market [Abstract]
Long-lived assets	9,342	11,517	13,587
Major Markets [Member] \| All Others [Member]
Long-Lived Assets by Major Market [Abstract]
Long-lived assets	$ 13,104	$ 9,935	$ 10,351

Dividends per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Dividends per Share [Abstract]
Payment of cash dividends									$ 76,058	$ 78,438	$ 81,187
Dividend Declared 2016-Q1 [Member]
Dividends per Share [Abstract]
Cash dividend paid (in dollars per share)								$ 0.355
Dividend Declared 2016-Q2 [Member]
Dividends per Share [Abstract]
Cash dividend paid (in dollars per share)							$ 0.355
Dividend Declared 2016-Q3 [Member]
Dividends per Share [Abstract]
Cash dividend paid (in dollars per share)						$ 0.355
Dividend Declared 2016-Q4 [Member]
Dividends per Share [Abstract]
Cash dividend paid (in dollars per share)					$ 0.355
Dividend Declared 2017-Q1 [Member]
Dividends per Share [Abstract]
Cash dividend paid (in dollars per share)				$ 0.36
Dividend Declared 2017-Q2 [Member]
Dividends per Share [Abstract]
Cash dividend paid (in dollars per share)			$ 0.36
Dividend Declared 2017-Q3 [Member]
Dividends per Share [Abstract]
Cash dividend paid (in dollars per share)		$ 0.36
Dividend Declared 2017-Q4 [Member]
Dividends per Share [Abstract]
Cash dividend paid (in dollars per share)	$ 0.36
Dividend Declared 2018-Q1 [Member]
Dividends per Share [Abstract]
Dividend payable per share (in dollars per share)									$ 0.365
Dividend payable, date to be paid									Mar. 14, 2018
Dividend payable, date of record									Feb. 26, 2018

Other Income (Expense), Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other Income (Expense), Net [Abstract]
Other income (expense), net	$ (8,916)	$ (18,265)	$ (32,743)
Foreign currency transaction losses on net monetary assets denominated in bolivar			10,200
Foreign currency translation expenses			17,000
Interest expense	$ 22,200	$ 15,600	$ 7,900

Cost of Sales (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Cost of Sales (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cost of Sales [Abstract]
Customs expense	$ 31,400	$ 0	$ 31,355	$ 0

Acquisitions (Details) - USD ($)
$ / shares in Units, $ in Thousands

3 Months Ended

12 Months Ended

Feb. 28, 2017

Sep. 30, 2017

Jun. 30, 2017

Mar. 31, 2016

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Cash paid for acquisition

$ 31,745

$ 8,692

$ 0

Vertical Eden, LLC [Member]

$ 114,954

^[1]

Useful life

15 years

Percentage of entity acquired

30.00%

70.00%

Cash paid for acquisition

$ 12,500

$ 3,300

Contingent consideration

1,500

Vertical Eden, LLC [Member] | Minimum [Member]

$ 2,500

Intangible assets

$ 4,400

Vertical Eden, LLC [Member] | Maximum [Member]

Useful life

3 years

Useful life

7 years

Treviso, LLC [Member]

Percentage of entity acquired

35.00%

Purchase price

$ 21,000

Possible earnout

1,000

Investment in equity investee

12,600

Value of shares issued

$ 8,400

Number of shares issued (in shares)

169,560

Share price (in dollars per share)

$ 49.54

Dr. Dana Beauty, LLC [Member]