Under Armour (UA) 10-K 20 Feb 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2014	Jun. 30, 2014	Jan. 31, 2015
Entity Information [Line Items]
Document Type	10-K
Amendment Flag	FALSE
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Trading Symbol	UA
Entity Registrant Name	Under Armour, Inc.
Entity Central Index Key	1336917
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float		$10,314,358,804
Class A Common Stock
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding			177,312,580
Class B Convertible Common Stock
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding			36,600,000

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Assets
Cash and cash equivalents	$593,175	$347,489
Accounts receivable, net	279,835	209,952
Inventories	536,714	469,006
Prepaid expenses and other current assets	87,177	63,987
Deferred income taxes	52,498	38,377
Total current assets	1,549,399	1,128,811
Property and equipment, net	305,564	223,952
Goodwill	123,256	122,244
Intangible assets, net	26,230	24,097
Deferred income taxes	33,570	31,094
Other long term assets	57,064	47,543
Total assets	2,095,083	1,577,741
Liabilities and Stockholders’ Equity
Revolving credit facility	0	100,000
Accounts payable	210,432	165,456
Accrued expenses	147,681	133,729
Current maturities of long term debt	28,951	4,972
Other current liabilities	34,563	22,473
Total current liabilities	421,627	426,630
Long term debt, net of current maturities	255,250	47,951
Other long term liabilities	67,906	49,806
Total liabilities	744,783	524,387
Commitments and contingencies (see Note 7)
Stockholders’ equity
Additional paid-in capital	508,350	397,248
Retained earnings	856,687	653,842
Accumulated other comprehensive income (loss)	-14,808	2,194
Total stockholders’ equity	1,350,300	1,053,354
Total liabilities and stockholders’ equity	2,095,083	1,577,741
Class A Common Stock
Stockholders’ equity
Common Stock, Value, Issued	59	57
Total stockholders’ equity	59	57
Class B Convertible Common Stock
Stockholders’ equity
Common Stock, Value, Issued	12	13
Total stockholders’ equity	$12	$13

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Class A Common Stock
Par value per share	$0.00	$0.00
Shares authorized	400,000,000	400,000,000
Shares issued	177,295,988	171,628,708
Shares authorized	177,295,988	171,628,708
Class B Convertible Common Stock
Par value per share	$0.00	$0.00
Shares authorized	36,600,000	40,000,000
Shares issued	36,600,000	40,000,000
Shares authorized	36,600,000	40,000,000

Consolidated_Statements_of_Inc

Consolidated Statements of Income (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Net revenues	$3,084,370	$2,332,051	$1,834,921
Cost of goods sold	1,572,164	1,195,381	955,624
Gross profit	1,512,206	1,136,670	879,297
Selling, general and administrative expenses	1,158,251	871,572	670,602
Income from operations	353,955	265,098	208,695
Interest expense, net	-5,335	-2,933	-5,183
Other expense, net	-6,410	-1,172	-73
Income before income taxes	342,210	260,993	203,439
Provision for income taxes	134,168	98,663	74,661
Net income	$208,042	$162,330	$128,778
Net income available per common share
Basic (USD Per Share)	$0.98	$0.77	$0.62
Diluted (USD Per Share)	$0.95	$0.75	$0.61
Weighted average common shares outstanding
Basic (In Shares)	213,227	210,696	208,686
Diluted (In Shares)	219,380	215,958	212,760

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Net income	$208,042	$162,330	$128,778
Other comprehensive income (loss):
Foreign currency translation adjustment	-16,743	-897	423
Unrealized gain (loss) on cash flow hedge, net of tax of ($408), $505 and $58 for the years ended December 31, 2014, 2013 and 2012.	-259	723	-83
Total other comprehensive income (loss)	-17,002	-174	340
Comprehensive income	$191,040	$162,156	$129,118

Consolidated_Statements_of_Com1

Consolidated Statements of Comprehensive Income (Parenthetical) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Unrealized gain (loss) on cash flow hedge, tax	($408)	$505	$58

Consolidated_Statements_Of_Sto

Consolidated Statements Of Stockholders' Equity And Comprehensive Income (USD $)	Total	Class A Common Stock	Class B Convertible Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
In Thousands, unless otherwise specified
Beginning balance at Dec. 31, 2011	$636,432	$54	$14	$268,172	$366,164	$2,028
Beginning balance (shares) at Dec. 31, 2011		161,984	45,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (shares)	2,436	2,436
Exercise of stock options	12,372	2		12,370
Shares withheld in consideration of employee tax obligations relative to stock-based compensation arrangements (shares)		-76
Shares withheld in consideration of employee tax obligations relative to stock-based compensation arrangements	-1,761				-1,761
Issuance of Class A Common Stock, net of forfeitures (shares)		178
Issuance of Class A Common Stock, net of forfeitures	3,246			3,246
Class B Convertible Common Stock converted to Class A Common Stock (shares)		2,400	-2,400
Class B Convertible Common Stock converted to Class A Common Stock	0	0	0
Stock-based compensation expense	19,845			19,845
Net excess tax benefits from stock-based compensation arrangements	17,670			17,670
Comprehensive income	129,118				128,778	340
Ending balance at Dec. 31, 2012	816,922	56	14	321,303	493,181	2,368
Ending balance (shares) at Dec. 31, 2012		166,922	42,600
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (shares)	1,822	1,822
Exercise of stock options	12,159	0		12,159
Shares withheld in consideration of employee tax obligations relative to stock-based compensation arrangements (shares)		-47
Shares withheld in consideration of employee tax obligations relative to stock-based compensation arrangements	-1,669				-1,669
Issuance of Class A Common Stock, net of forfeitures (shares)		332
Issuance of Class A Common Stock, net of forfeitures	3,439			3,439
Class B Convertible Common Stock converted to Class A Common Stock (shares)		2,600	-2,600
Class B Convertible Common Stock converted to Class A Common Stock	0	1	-1
Stock-based compensation expense	43,184			43,184
Net excess tax benefits from stock-based compensation arrangements	17,163			17,163
Comprehensive income	162,156				162,330	-174
Ending balance at Dec. 31, 2013	1,053,354	57	13	397,248	653,842	2,194
Ending balance (shares) at Dec. 31, 2013		171,629	40,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (shares)	1,454	1,454
Exercise of stock options	11,259	1		11,258
Shares withheld in consideration of employee tax obligations relative to stock-based compensation arrangements (shares)		-95
Shares withheld in consideration of employee tax obligations relative to stock-based compensation arrangements	-5,197				-5,197
Issuance of Class A Common Stock, net of forfeitures (shares)		908
Issuance of Class A Common Stock, net of forfeitures	12,067			12,067
Class B Convertible Common Stock converted to Class A Common Stock (shares)		3,400	-3,400
Class B Convertible Common Stock converted to Class A Common Stock	0	1	-1
Stock-based compensation expense	50,812			50,812
Net excess tax benefits from stock-based compensation arrangements	36,965			36,965
Comprehensive income	191,040				208,042	-17,002
Ending balance at Dec. 31, 2014	$1,350,300	$59	$12	$508,350	$856,687	($14,808)
Ending balance (shares) at Dec. 31, 2014		177,296	36,600

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities
Net income	$208,042	$162,330	$128,778
Adjustments to reconcile net income to net cash used in operating activities
Depreciation and amortization	72,093	50,549	43,082
Unrealized foreign currency exchange rate losses (gains)	11,739	1,905	-2,464
Loss on disposal of property and equipment	261	332	524
Stock-based compensation	50,812	43,184	19,845
Deferred income taxes	-17,584	-18,832	-12,973
Changes in reserves and allowances	31,350	13,945	13,916
Changes in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable	-101,057	-35,960	-53,433
Inventories	-84,658	-156,900	4,699
Prepaid expenses and other assets	-33,345	-19,049	-4,060
Accounts payable	49,137	14,642	35,370
Accrued expenses and other liabilities	28,856	56,481	21,966
Income taxes payable and receivable	3,387	7,443	4,511
Net cash provided by operating activities	219,033	120,070	199,761
Cash flows from investing activities
Purchases of property and equipment	-140,528	-87,830	-50,650
Purchase of business	-10,924	-148,097	0
Purchases of other assets	-860	-475	-1,310
Change in loans receivable	0	-1,700	0
Change in restricted cash	0	0	5,029
Net cash used in investing activities	-152,312	-238,102	-46,931
Cash flows from financing activities
Proceeds from revolving credit facility	0	100,000	0
Payments on revolving credit facility	100,000	0	0
Proceeds from term loan	250,000	0	0
Payments on term loan	-13,750	0	-25,000
Proceeds from long term debt	0	0	50,000
Payments on long term debt	-4,972	-5,471	-44,330
Excess tax benefits from stock-based compensation arrangements	36,965	17,167	17,868
Proceeds from exercise of stock options and other stock issuances	15,776	15,099	14,776
Payments of debt financing costs	-1,713	0	-1,017
Net cash provided by financing activities	182,306	126,795	12,297
Effect of exchange rate changes on cash and cash equivalents	-3,341	-3,115	1,330
Net increase in cash and cash equivalents	245,686	5,648	166,457
Cash and cash equivalents
Beginning of period	347,489	341,841	175,384
End of period	593,175	347,489	341,841
Increase in accrual for property and equipment	4,922	3,786	12,137
Noncash or Part Noncash Acquisition, Value of Assets Acquired	11,233	0	0
Cash paid for income taxes	103,284	85,570	57,739
Cash paid for interest, net of capitalized interest	$4,146	$1,505	$3,306

Description_of_the_Business

Description of the Business	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
Description of the Business	Description of the Business
	Under Armour, Inc. is a developer, marketer and distributor of branded performance apparel, footwear and accessories. These products are sold worldwide and worn by athletes at all levels, from youth to professional on playing fields around the globe, as well as by consumers with active lifestyles.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies
	Basis of Presentation
	The accompanying consolidated financial statements include the accounts of Under Armour, Inc. and its wholly owned subsidiaries (the “Company”). All intercompany balances and transactions have been eliminated. The accompanying consolidated financial statements were prepared in accordance with accounting principles generally accepted in the United States of America.
	On June 11, 2012 and March 17, 2014 the Board of Directors declared two-for-one stock splits of the Company's Class A and Class B common stock, which were effected in the form of a 100% common stock dividend distributed on July 9, 2012 and April 14, 2014, respectively. Stockholders' equity and all references to share and per share amounts in the accompanying consolidated financial statements have been retroactively adjusted to reflect these two-for-one stock splits for all periods presented.
	Cash and Cash Equivalents
	The Company considers all highly liquid investments with an original maturity of three months or less at date of inception to be cash and cash equivalents. Included in interest expense, net for the years ended December 31, 2014, 2013 and 2012 was interest income of $192.0 thousand, $23.7 thousand and $25.2 thousand, respectively, related to cash and cash equivalents.
	Concentration of Credit Risk
	Financial instruments that subject the Company to significant concentration of credit risk consist primarily of accounts receivable. The majority of the Company’s accounts receivable is due from large sporting goods retailers. Credit is extended based on an evaluation of the customer’s financial condition and collateral is not required. The Company had two customers in North America that individually accounted for 23.4% and 11.1% of accounts receivable as of December 31, 2014. The Company's largest customer accounted for 14.4%, 16.6% and 16.6% of net revenues for the years ended December 31, 2014, 2013 and 2012, respectively.
	Allowance for Doubtful Accounts
	The Company makes ongoing estimates relating to the collectability of accounts receivable and maintains an allowance for estimated losses resulting from the inability of its customers to make required payments. In determining the amount of the reserve, the Company considers historical levels of credit losses and significant economic developments within the retail environment that could impact the ability of its customers to pay outstanding balances and makes judgments about the creditworthiness of significant customers based on ongoing credit evaluations. Because the Company cannot predict future changes in the financial stability of its customers, actual future losses from uncollectible accounts may differ from estimates. If the financial condition of customers were to deteriorate, resulting in their inability to make payments, a larger reserve might be required. In the event the Company determines a smaller or larger reserve is appropriate, it would record a benefit or charge to selling, general and administrative expense in the period in which such a determination was made. As of December 31, 2014 and 2013, the allowance for doubtful accounts was $3.7 million and $2.9 million, respectively.
	Inventories
	Inventories consist primarily of finished goods. Costs of finished goods inventories include all costs incurred to bring inventory to its current condition, including inbound freight, duties and other costs. The Company values its inventory at standard cost which approximates landed cost, using the first-in, first-out method of cost determination. Market value is estimated based upon assumptions made about future demand and retail market conditions. If the Company determines that the estimated market value of its inventory is less than the carrying value of such inventory, it records a charge to cost of goods sold to reflect the lower of cost or market. If actual market conditions are less favorable than those projected by the Company, further adjustments may be required that would increase the cost of goods sold in the period in which such a determination was made.
	Income Taxes
	Income taxes are accounted for under the asset and liability method. Deferred income tax assets and liabilities are established for temporary differences between the financial reporting basis and the tax basis of the Company’s assets and liabilities at tax rates expected to be in effect when such assets or liabilities are realized or settled. Deferred income tax assets are reduced by valuation allowances when necessary.
	Assessing whether deferred tax assets are realizable requires significant judgment. The Company considers all available positive and negative evidence, including historical operating performance and expectations of future operating performance. The ultimate realization of deferred tax assets is often dependent upon future taxable income and therefore can be uncertain. To the extent the Company believes it is more likely than not that all or some portion of the asset will not be realized, valuation allowances are established against the Company’s deferred tax assets, which increase income tax expense in the period when such a determination is made.
	Income taxes include the largest amount of tax benefit for an uncertain tax position that is more likely than not to be sustained upon audit based on the technical merits of the tax position. Settlements with tax authorities, the expiration of statutes of limitations for particular tax positions, or obtaining new information on particular tax positions may cause a change to the effective tax rate. The Company recognizes accrued interest and penalties related to unrecognized tax benefits in the provision for income taxes on the consolidated statements of income.
	Property and Equipment
	Property and equipment are stated at cost, including the cost of internal labor for software customized for internal use, less accumulated depreciation and amortization. Property and equipment is depreciated using the straight-line method over the estimated useful lives of the assets: 3 to 10 years for furniture, office equipment, software and plant equipment and 10 to 35 years for site improvements, buildings and building equipment. Leasehold and tenant improvements are amortized over the shorter of the lease term or the estimated useful lives of the assets. The cost of in-store apparel and footwear fixtures and displays are capitalized, included in furniture, fixtures and displays, and depreciated over 3 years. The Company periodically reviews assets’ estimated useful lives based upon actual experience and expected future utilization. A change in useful life is treated as a change in accounting estimate and is applied prospectively.
	The Company capitalizes the cost of interest for long term property and equipment projects based on the Company’s weighted average borrowing rates in place while the projects are in progress. Capitalized interest was $0.4 million and $0.4 million as of December 31, 2014 and 2013, respectively.
	Upon retirement or disposition of property and equipment, the cost and accumulated depreciation are removed from the accounts and any resulting gain or loss is reflected in selling, general and administrative expenses for that period. Major additions and betterments are capitalized to the asset accounts while maintenance and repairs, which do not improve or extend the lives of assets, are expensed as incurred.
	Goodwill, Intangible Assets and Long-Lived Assets
	Goodwill and intangible assets are recorded at their estimated fair values at the date of acquisition and are allocated to the reporting units that are expected to receive the related benefits. Goodwill and indefinite lived intangible assets are not amortized and are required to be tested for impairment at least annually or sooner whenever events or changes in circumstances indicate that the assets may be impaired. In conducting an annual impairment test, the Company first reviews qualitative factors to determine whether it is more likely than not that the fair value of the reporting unit is less than its carrying amount. If factors indicate that is the case, the Company performs a quantitative assessment over relevant reporting units, analyzing the expected present value of future cash flows and quantify the amount of impairment, if any. The Company performs its annual impairment tests in the fourth quarter of each fiscal year.
	The Company continually evaluates whether events and circumstances have occurred that indicate the remaining estimated useful life of long-lived assets may warrant revision or that the remaining balance may not be recoverable. These factors may include a significant deterioration of operating results, changes in business plans, or changes in anticipated cash flows. When factors indicate that an asset should be evaluated for possible impairment, the Company reviews long-lived assets to assess recoverability from future operations using undiscounted cash flows. If future undiscounted cash flows are less than the carrying value, an impairment is recognized in earnings to the extent that the carrying value exceeds fair value.
	Accrued Expenses
	At December 31, 2014, accrued expenses primarily included $61.4 million and $14.0 million of accrued compensation and benefits and marketing expenses, respectively. At December 31, 2013, accrued expenses primarily included $56.7 million and $11.9 million of accrued compensation and benefits and marketing expenses, respectively.
	Foreign Currency Translation and Transactions
	The functional currency for each of the Company’s wholly owned foreign subsidiaries is generally the applicable local currency. The translation of foreign currencies into U.S. dollars is performed for assets and liabilities using current foreign currency exchange rates in effect at the balance sheet date and for revenue and expense accounts using average foreign currency exchange rates during the period. Capital accounts are translated at historical foreign currency exchange rates. Translation gains and losses are included in stockholders’ equity as a component of accumulated other comprehensive income. Adjustments that arise from foreign currency exchange rate changes on transactions, primarily driven by intercompany transactions, denominated in a currency other than the functional currency are included in other expense, net on the consolidated statements of income.
	Derivatives and Hedging Activities
	The Company uses derivative financial instruments in the form of foreign currency forward and interest rate swap contracts to minimize the risk associated with foreign currency exchange rate and interest rate fluctuations. The Company accounts for derivative financial instruments pursuant to applicable accounting guidance. This guidance establishes accounting and reporting standards for derivative financial instruments and requires all derivatives to be recognized as either assets or liabilities on the balance sheet and to be measured at fair value. Unrealized derivative gain positions are recorded as other current assets or other long term assets, and unrealized derivative loss positions are recorded as accrued expenses or other long term liabilities, depending on the derivative financial instrument’s maturity date.
	Currently, the majority of the Company’s foreign currency forward contracts are not designated as cash flow hedges, and accordingly, changes in their fair value are included in other expense, net on the consolidated statements of income. During 2014, the Company began entering into foreign currency forward contracts designated as cash flow hedges, and consequently, changes in fair value, excluding any ineffective portion, are recorded in other comprehensive income until net income is affected by the variability in cash flows of the hedged transaction. The effective portion is generally released to net income after the maturity of the related derivative and is classified in the same manner as the underlying exposure. Additionally, the Company has designated its interest rate swap contract as a cash flow hedge and accordingly, the effective portion of changes in fair value are recorded in other comprehensive income and reclassified into interest expense over the life of the underlying debt obligation. The ineffective portion, if any, is recognized in current period earnings. The Company does not enter into derivative financial instruments for speculative or trading purposes.
	Revenue Recognition
	The Company recognizes revenue pursuant to applicable accounting standards. Net revenues consist of both net sales and license and other revenues. Net sales are recognized upon transfer of ownership, including passage of title to the customer and transfer of risk of loss related to those goods. Transfer of title and risk of loss is based upon shipment under free on board shipping point for most goods or upon receipt by the customer depending on the country of the sale and the agreement with the customer. In some instances, transfer of title and risk of loss takes place at the point of sale, for example, at the Company’s brand and factory house stores. The Company may also ship product directly from its supplier to the customer and recognize revenue when the product is delivered to and accepted by the customer. License and other revenues are primarily recognized based upon shipment of licensed products sold by the Company’s licensees. Sales taxes imposed on the Company’s revenues from product sales are presented on a net basis on the consolidated statements of income and therefore do not impact net revenues or costs of goods sold.
	The Company records reductions to revenue for estimated customer returns, allowances, markdowns and discounts. The Company bases its estimates on historical rates of customer returns and allowances as well as the specific identification of outstanding returns, markdowns and allowances that have not yet been received by the Company. The actual amount of customer returns and allowances, which is inherently uncertain, may differ from the Company’s estimates. If the Company determines that actual or expected returns or allowances are significantly higher or lower than the reserves it established, it would record a reduction or increase, as appropriate, to net sales in the period in which it makes such a determination. Provisions for customer specific discounts are based on contractual obligations with certain major customers. Reserves for returns, allowances, markdowns and discounts are recorded as an offset to accounts receivable as settlements are made through offsets to outstanding customer invoices. As of December 31, 2014 and 2013, there were $68.9 million and $43.8 million, respectively, in reserves for customer returns, allowances, markdowns and discounts.
	Advertising Costs
	Advertising costs are charged to selling, general and administrative expenses. Advertising production costs are expensed the first time an advertisement related to such production costs is run. Media (television, print and radio) placement costs are expensed in the month during which the advertisement appears, and costs related to event sponsorships are expensed when the event occurs. In addition, advertising costs include sponsorship expenses. Accounting for sponsorship payments is based upon specific contract provisions and the payments are generally expensed uniformly over the term of the contract after recording expense related to specific performance incentives once they are deemed probable. Advertising expense, including amortization of in-store marketing fixtures and displays, was $333.0 million, $246.5 million and $205.4 million for the years ended December 31, 2014, 2013 and 2012, respectively. At December 31, 2014 and 2013, prepaid advertising costs were $31.1 million and $22.0 million, respectively.
	Shipping and Handling Costs
	The Company charges certain customers shipping and handling fees. These fees are recorded in net revenues. The Company includes the majority of outbound handling costs as a component of selling, general and administrative expenses. Outbound handling costs include costs associated with preparing goods to ship to customers and certain costs to operate the Company’s distribution facilities. These costs, included within selling, general and administrative expenses, were $55.3 million, $46.1 million and $34.8 million for the years ended December 31, 2014, 2013 and 2012, respectively. The Company includes outbound freight costs associated with shipping goods to customers as a component of cost of goods sold.
	Minority Investment
	The Company holds a minority investment in Dome Corporation (“Dome”), the Company’s Japanese licensee. The Company invested ¥1,140.0 million, or $15.5 million, in exchange for 19.5% common stock ownership in Dome. As of December 31, 2014 and 2013, the carrying value of the Company’s investment was $13.4 million and $15.2 million, respectively, and was included in other long term assets on the consolidated balance sheet. The investment is subject to foreign currency translation rate fluctuations as it is held by the Company’s European subsidiary.
	The Company accounts for its investment in Dome under the cost method given that it does not have the ability to exercise significant influence. Additionally, the Company concluded that no event or change in circumstances occurred during the year ended December 31, 2014 that may have a significant adverse effect on the fair value of the investment.
	Earnings per Share
	Basic earnings per common share is computed by dividing net income available to common stockholders for the period by the weighted average number of common shares outstanding during the period. Any stock-based compensation awards that are determined to be participating securities, which are stock-based compensation awards that entitle the holders to receive dividends prior to vesting, are included in the calculation of basic earnings per share using the two class method. Diluted earnings per common share is computed by dividing net income available to common stockholders for the period by the diluted weighted average common shares outstanding during the period. Diluted earnings per share reflects the potential dilution from common shares issuable through stock options, warrants, restricted stock units and other equity awards. Refer to Note 11 for further discussion of earnings per share.
	Stock-Based Compensation
	The Company accounts for stock-based compensation in accordance with accounting guidance that requires all stock-based compensation awards granted to employees and directors to be measured at fair value and recognized as an expense in the financial statements. In addition, this guidance requires that excess tax benefits related to stock-based compensation awards be reflected as financing cash flows.
	The Company uses the Black-Scholes option-pricing model to estimate the fair market value of stock-based compensation awards. The Company uses the “simplified method” to estimate the expected life of options, as permitted by accounting guidance. The “simplified method” calculates the expected life of a stock option equal to the time from grant to the midpoint between the vesting date and contractual term, taking into account all vesting tranches. The risk free interest rate is based on the yield for the U.S. Treasury bill with a maturity equal to the expected life of the stock option. Expected volatility is based on the Company's historical average. Compensation expense is recognized net of forfeitures on a straight-line basis over the total vesting period, which is the implied requisite service period. Compensation expense for performance-based awards is recorded over the implied requisite service period when achievement of the performance target is deemed probable. The forfeiture rate is estimated at the date of grant based on historical rates.
	The Company issues new shares of Class A Common Stock upon exercise of stock options, grant of restricted stock or share unit conversion. Refer to Note 12 for further details on stock-based compensation.
	Management Estimates
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from these estimates.
	Fair Value of Financial Instruments
	The carrying amounts shown for the Company’s cash and cash equivalents, accounts receivable and accounts payable approximate fair value because of the short term maturity of those instruments. The fair value of the long term debt approximates its carrying value based on the variable nature of interest rates and current market rates available to the Company. The fair value of foreign currency forward contracts is based on the net difference between the U.S. dollars to be received or paid at the contracts’ settlement date and the U.S. dollar value of the foreign currency to be sold or purchased at the current forward exchange rate. The fair value of the interest rate swap contract is based on the net difference between the fixed interest to be paid and variable interest to be received over the term of the contract based on current market rates.
	Recently Issued Accounting Standards
	In May 2014, the Financial Accounting Standards Board (“FASB”) issued an Accounting Standards Update which supersedes the most current revenue recognition requirements. The new revenue recognition standard requires entities to recognize revenue in a way that depicts the transfer of goods or services to customers in an amount that reflects the consideration which the entity expects to be entitled to in exchange for those goods or services. This guidance is effective for annual and interim reporting periods beginning after December 15, 2016, with early adoption not permitted. The Company is currently evaluating the standard to determine the impact of its adoption on the Company's consolidated financial statements.
	In January 2015, the FASB issued an Accounting Standards Update which eliminates from GAAP the concept of extraordinary items and the need to separately classify, present, and disclose extraordinary events and transactions. This guidance is effective for annual and interim reporting periods beginning after December 15, 2015, with early adoption permitted provided that the guidance is applied from the beginning of the fiscal year of adoption. The adoption of this pronouncement is not expected to impact the Company's consolidated financial statements.
	Recently Adopted Accounting Standards
	In July 2013, the FASB issued an Accounting Standards Update which requires that an unrecognized tax benefit, or a portion of an unrecognized tax benefit, should be presented in the financial statements as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward, with certain exceptions. This guidance is effective for annual and interim reporting periods beginning after December 15, 2013. The adoption of this pronouncement did not have a material impact on the Company's consolidated financial statements.
	In February 2013, the FASB issued an Accounting Standards Update which requires companies to present either in a single note or parenthetically on the face of the financial statements, the effect of significant amounts reclassified from each component of accumulated other comprehensive income based on its source and the income statement line items affected by the reclassification. This guidance is effective for annual and interim reporting periods beginning after December 15, 2012. The adoption of this pronouncement did not have a material impact on the Company's consolidated financial statements.

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2014
Acquisitions [Abstract]
Business Combination Disclosure [Text Block]	Acquisitions
	MapMyFitness
	On December 6, 2013, the Company acquired 100% of the outstanding equity of MapMyFitness, Inc., a digital connected fitness platform, for $150.0 million in cash. The purchase price was financed through $100.0 million in debt under the Company's existing revolving credit facility and cash on hand.
	The acquisition was accounted for as a business combination. The Company allocated the total purchase price to the tangible and intangible assets acquired and liabilities assumed based on their estimated fair values on the acquisition date, with the remaining unallocated purchase price recorded as goodwill. As a result of the initial purchase price allocation, the Company recorded intangible assets of $20.6 million, goodwill of $122.2 million, and other net assets of $6.6 million, primarily consisting of $4.7 million of net deferred tax assets.
	Intangible assets consist of $12.0 million of technology, $5.0 million of trade name, and $3.6 million of customer relationships. The Company estimated the acquisition date fair values of the intangible assets based on income based discounted cash flow models using estimates and assumptions regarding future operations. The Company will amortize the intangible assets on a straight-line basis over their estimated useful lives of two to seven years.
	The goodwill recorded as a result of the acquisition primarily reflects unidentified intangible assets acquired, including the value of integrating and innovating acquired technologies and engaging and growing the digital community. The acquired goodwill has been allocated primarily within the Company's North America operating segment as well as the MapMyFitness operating segment. The goodwill associated with this acquisition is not deductible for tax purposes.
	In connection with this acquisition, the Company incurred acquisition related expenses of approximately $2.5 million. These expenses were included in selling, general and administrative expenses on the consolidated statements of income during the year ended December 31, 2013. This acquisition did not have a material impact to the Company’s consolidated statements of income during the year ended December 31, 2013.
	During the three months ended March 31, 2014, the Company finalized its valuation of the assets acquired and liabilities assumed as of the acquisition date and no adjustments were made to the preliminary purchase price allocation recorded as of December 31, 2013.

Property_And_Equipment_Net

Property And Equipment, Net	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	4. Property and Equipment, Net
	Property and equipment consisted of the following:
		December 31,
	(In thousands)	2014			2013
	Leasehold and tenant improvements	$	128,088		$	97,776
	Furniture, fixtures and displays	80,035			68,045
	Buildings	46,419			45,903
	Software	67,506			51,984
	Office equipment	51,531			39,551
	Plant equipment	70,317			45,509
	Land	17,628			17,628
	Construction in progress	57,677			28,471
	Other	3,175			1,219
	Subtotal property and equipment	522,376			396,086
	Accumulated depreciation	(216,812		)	(172,134		)
	Property and equipment, net	$	305,564		$	223,952
	Construction in progress primarily includes costs incurred for software systems, leasehold improvements and in-store fixtures and displays not yet placed in use.
	Depreciation expense related to property and equipment was $63.6 million, $48.3 million and $39.8 million for the years ended December 31, 2014, 2013 and 2012, respectively.

Goodwill_and_Intangible_Assets

Goodwill and Intangible Assets, Net	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets Disclosure	. Goodwill and Intangible Assets, Net
	The following table summarizes changes in the carrying amount of the Company’s goodwill by reportable segment as of the periods indicated:
	(In thousands)		North America		Other foreign countries and businesses			Total
	Balance as of December 31, 2013		$	119,799	$	2,445		$	122,244
	Goodwill acquired		—		1,012			1,012
	Balance as of December 31, 2014		$	119,799	$	3,457		$	123,256
	During 2014, the Company acquired $1.0 million of goodwill in connection with the acquisition of certain assets of its former distributor in Mexico, which was accounted for as a business combination.
	The following table summarizes the Company’s intangible assets as of the periods indicated:
			31-Dec-14							31-Dec-13
	(In thousands)		Gross		Accumulated			Net Carrying		Gross		Accumulated			Net Carrying
			Carrying		Amortization			Amount		Carrying		Amortization			Amount
			Amount							Amount
	Intangible assets subject to amortization:
	Technology		$	12,000	$	(1,907	)	$	10,093	$	12,000	$	(126	)	$	11,874
	Trade name		5,000		(1,353		)	3,647		5,000		(53		)	4,947
	Customer relationships		11,927		(4,692		)	7,235		3,600		(38		)	3,562
	Lease-related intangible assets		3,896		(2,762		)	1,134		3,896		(2,605		)	1,291
	Other		2,196		(893		)	1,303		1,266		(532		)	734
	Total		$	35,019	$	(11,607	)	$	23,412	$	25,762	$	(3,354	)	$	22,408
	Indefinite-lived intangible assets							2,818							1,689
	Intangible assets, net							$	26,230						$	24,097
	Technology, trade-name and customer relationship intangible assets were acquired with the purchase of MapMyFitness and are amortized on a straight-line basis over 84 months, 48 months and 24 months, respectively. Customer relationship intangible assets were also acquired with the acquisition of certain assets of the Company's former distributor in Mexico and are amortized on a straight-line basis over 36 months. Lease-related intangible assets were acquired with the purchase of the Company’s corporate headquarters and are amortized over the remaining third party lease terms, which ranged from 9 months to 15 years on the date of purchase. Other intangible assets are amortized using estimated useful lives of 55 months to 120 months with no residual value. Amortization expense, which is included in selling, general and administrative expenses, was $8.5 million, $1.6 million and $2.2 million for the years ended December 31, 2014, 2013 and 2012, respectively. The following is the estimated amortization expense for the Company’s intangible assets as of December 31, 2014:
	(In thousands)
	2015	$	7,862
	2016	6,118
	2017	3,236
	2018	2,074
	2019	1,966
	2020 and thereafter	2,156
	Amortization expense of intangible assets	$	23,412
	At December 31, 2014, 2013 and 2012, the Company determined that its goodwill and indefinite-lived intangible assets were not impaired.

Credit_Facility_and_Long_Term_

Credit Facility and Long Term Debt	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Credit Facility and Long Term Debt	Credit Facility and Long Term Debt
	Credit Facility
	In May 2014, the Company entered into a new unsecured $650.0 million credit facility and terminated its prior $325.0 million secured revolving credit facility. The credit agreement has a term of five years through May 2019, with permitted extensions under certain circumstances. The credit agreement provides for a committed revolving credit facility of $400.0 million, in addition to an aggregate term loan commitment of $250.0 million, consisting of a $150.0 million term loan, drawn at the closing of the credit agreement, and $100.0 million delayed draw term loan drawn in November 2014 for general corporate purposes. At the Company's request and the lenders' consent, the revolving credit facility or term loans may be increased by up to an additional $150.0 million. Borrowings under the revolving credit facility may be made in U.S. Dollars, Euros, Pounds Sterling, Japanese Yen and Canadian Dollars. Up to $50.0 million of the facility may be used for the issuance of letters of credit and up to $50.0 million of the facility may be used for the issuance of swingline loans. There were no significant letters of credit and no swingline loans outstanding as of December 31, 2014.
	The credit agreement contains negative covenants that, subject to significant exceptions, limit the ability of the Company and its subsidiaries to, among other things, incur additional indebtedness, make restricted payments, pledge their assets as security, make investments, loans, advances, guarantees and acquisitions, undergo fundamental changes and enter into transactions with affiliates. The Company is also required to maintain a ratio of consolidated EBITDA, as defined in the credit agreement, to consolidated interest expense of not less than 3.50 to 1.00 and is not permitted to allow the ratio of consolidated total indebtedness to consolidated EBITDA to be greater than 3.25 to 1.00 ("consolidated leverage ratio"). As of December 31, 2014, the Company was in compliance with these ratios. In addition, the credit agreement contains events of default that are customary for a facility of this nature, and includes a cross default provision whereby an event of default under other material indebtedness, as defined in the credit agreement, will be considered an event of default under the credit agreement.
	Borrowings under the credit agreement bear interest at a rate per annum equal to, at the Company’s option, either (a) an alternate base rate, or (b) a rate based on the rates applicable for deposits in the interbank market for U.S. Dollars or the applicable currency in which the loans are made (“adjusted LIBOR”), plus in each case an applicable margin. The applicable margin for loans will be adjusted by reference to a grid (the “Pricing Grid”) based on the consolidated leverage ratio and ranges between 1.00% to 1.25% for adjusted LIBOR loans and 0.00% to 0.25% for alternate base rate loans. The interest rate under both term loans was 1.2% during the year ended December 31, 2014. No balance was outstanding under the Company’s revolving credit facility as of December 31, 2014. Additionally, the Company pays a commitment fee on the average daily unused amount of the revolving credit facility, a ticking fee on the undrawn amounts under the delayed draw term loan and certain fees with respect to letters of credit. As of December 31, 2014, the commitment fee was 12.5 basis points.
	The Company used $100.0 million of the proceeds from the $150.0 million loan to repay the $100.0 million outstanding under the Company's prior revolving credit facility. The Company incurred and capitalized $1.7 million in deferred financing costs in connection with the credit facility.
	Other Long Term Debt
	The Company has long term debt agreements with various lenders to finance the acquisition or lease of qualifying capital investments. Loans under these agreements are collateralized by a first lien on the related assets acquired. At December 31, 2014, 2013 and 2012, the outstanding principal balance under these agreements was $2.0 million, $4.9 million and $11.9 million, respectively. Currently, advances under these agreements bear interest rates which are fixed at the time of each advance. The weighted average interest rates on outstanding borrowings were 3.1%, 3.3% and 3.7% for the years ended December 31, 2014, 2013 and 2012, respectively.
	In December 2012, the Company entered into a $50.0 million recourse loan collateralized by the land, buildings and tenant improvements comprising the Company's corporate headquarters. The loan has a seven year term and maturity date of December 2019. The loan bears interest at one month LIBOR plus a margin of 1.50%, and allows for prepayment without penalty. The loan includes covenants and events of default substantially consistent with the new credit agreement discussed above. The loan also requires prior approval of the lender for certain matters related to the property, including transfers of any interest in the property. As of December 31, 2014, 2013 and 2012, the outstanding balance on the loan was $46.0 million, $48.0 million and $50.0 million, respectively. The weighted average interest rate on the loan was 1.7% for the years ended December 31, 2014, 2013 and 2012.
	The following are the scheduled maturities of long term debt as of December 31, 2014:
	(In thousands)
	2015	$	28,951
	2016	27,000
	2017	27,000
	2018	27,000
	2019	138,250
	2020 and thereafter	36,000
	Total scheduled maturities of long term debt	284,201
	Less current maturities of long term debt	(28,951		)
	Long term debt obligations	$	255,250
	Interest expense, net was $5.3 million, $2.9 million and $5.2 million for the years ended December 31, 2014, 2013 and 2012, respectively. Interest expense includes the amortization of deferred financing costs and interest expense under the credit and long term debt facilities.
	The Company monitors the financial health and stability of its lenders under the credit and other long term debt facilities, however during any period of significant instability in the credit markets lenders could be negatively impacted in their ability to perform under these facilities.

Commitments_And_Contingencies

Commitments And Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	Commitments and Contingencies
	Obligations Under Operating Leases
	The Company leases warehouse space, office facilities, space for its brand and factory house stores and certain equipment under non-cancelable operating leases. The leases expire at various dates through 2028, excluding extensions at the Company’s option, and include provisions for rental adjustments. The table below includes executed lease agreements for brand and factory house stores that the Company did not yet occupy as of December 31, 2014 and does not include contingent rent the Company may incur at its stores based on future sales above a specified minimum or payments made for maintenance, insurance and real estate taxes. The following is a schedule of future minimum lease payments for non-cancelable real property operating leases as of December 31, 2014 as well as significant operating lease agreements entered into during the period after December 31, 2014 through the date of this report:
	(In thousands)
	2015		$	56,452
	2016		57,079
	2017		52,172
	2018		48,345
	2019		44,313
	2020 and thereafter		214,214
	Total future minimum lease payments		$	472,575
	Included in selling, general and administrative expense was rent expense of $59.0 million, $41.8 million and $31.1 million for the years ended December 31, 2014, 2013 and 2012, respectively, under non-cancelable operating lease agreements. Included in these amounts was contingent rent expense of $11.0 million, $7.8 million and $6.2 million for the years ended December 31, 2014, 2013 and 2012, respectively.
	Sponsorships and Other Marketing Commitments
	Within the normal course of business, the Company enters into contractual commitments in order to promote the Company’s brand and products. These commitments include sponsorship agreements with teams and athletes on the collegiate and professional levels, official supplier agreements, athletic event sponsorships and other marketing commitments. The following is a schedule of the Company’s future minimum payments under its sponsorship and other marketing agreements as of December 31, 2014, as well as significant sponsorship and other marketing agreements entered into during the period after December 31, 2014 through the date of this report:
	(In thousands)
	2015	$	90,056
	2016	71,654
	2017	56,734
	2018	44,982
	2019	33,155
	2020 and thereafter	96,345
	Total future minimum sponsorship and other marketing payments	$	392,926
	The amounts listed above are the minimum obligations required to be paid under the Company’s sponsorship and other marketing agreements. The amounts listed above do not include additional performance incentives and product supply obligations provided under certain agreements. It is not possible to determine how much the Company will spend on product supply obligations on an annual basis as contracts generally do not stipulate specific cash amounts to be spent on products. The amount of product provided to the sponsorships depends on many factors including general playing conditions, the number of sporting events in which they participate and the Company’s decisions regarding product and marketing initiatives. In addition, the costs to design, develop, source and purchase the products furnished to the endorsers are incurred over a period of time and are not necessarily tracked separately from similar costs incurred for products sold to customers.
	Other
	From time to time, the Company is involved in litigation and other proceedings, including matters related to commercial and intellectual property disputes, as well as trade, regulatory and other claims related to its business. The Company believes that all current proceedings are routine in nature and incidental to the conduct of its business, and that the ultimate resolution of any such proceedings will not have a material adverse effect on its consolidated financial position, results of operations or cash flows.
	In connection with various contracts and agreements, the Company has agreed to indemnify counterparties against certain third party claims relating to the infringement of intellectual property rights and other items. Generally, such indemnification obligations do not apply in situations in which the counterparties are grossly negligent, engage in willful misconduct, or act in bad faith. Based on the Company’s historical experience and the estimated probability of future loss, the Company has determined that the fair value of such indemnifications is not material to its consolidated financial position or results of operations.

Stockholders_Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2014
Stockholders' Equity Note [Abstract]
Stockholders' Equity	Stockholders’ Equity
	The Company’s Class A Common Stock and Class B Convertible Common Stock have an authorized number of shares at December 31, 2014 of 400.0 million shares and 36.6 million shares, respectively, and each have a par value of $0.0003 1/3 per share. Holders of Class A Common Stock and Class B Convertible Common Stock have identical rights, including liquidation preferences, except that the holders of Class A Common Stock are entitled to one vote per share and holders of Class B Convertible Common Stock are entitled to 10 votes per share on all matters submitted to a stockholder vote. Class B Convertible Common Stock may only be held by Kevin Plank, the Company’s founder and Chief Executive Officer, or a related party of Mr. Plank, as defined in the Company’s charter. As a result, Mr. Plank has a majority voting control over the Company. Upon the transfer of shares of Class B Convertible Stock to a person other than Mr. Plank or a related party of Mr. Plank, the shares automatically convert into shares of Class A Common Stock on a one-for-one basis. In addition, all of the outstanding shares of Class B Convertible Common Stock will automatically convert into shares of Class A Common Stock on a one-for-one basis upon the death or disability of Mr. Plank or on the record date for any stockholders’ meeting upon which the shares of Class A Common Stock and Class B Convertible Common Stock beneficially owned by Mr. Plank is less than 15% of the total shares of Class A Common Stock and Class B Convertible Common Stock outstanding. Holders of the Company’s common stock are entitled to receive dividends when and if authorized and declared out of assets legally available for the payment of dividends.
	During the year ended December 31, 2014, 3.4 million shares of Class B Convertible Common Stock were converted into shares of Class A Common Stock on a one-for-one basis in connection with stock sales.

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
Fair Value Measurements	Fair Value Measurements
	Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (an exit price). The fair value accounting guidance outlines a valuation framework, creates a fair value hierarchy in order to increase the consistency and comparability of fair value measurements and the related disclosures, and prioritizes the inputs used in measuring fair value as follows:
	Level 1:	Observable inputs such as quoted prices in active markets;
	Level 2:	Inputs, other than quoted prices in active markets, that are observable either directly or indirectly; and
	Level 3:	Unobservable inputs for which there is little or no market data, which require the reporting entity to develop its own assumptions.
	Financial assets and (liabilities) measured at fair value are set forth in the table below:
			31-Dec-14							31-Dec-13
	(In thousands)		Level 1		Level 2			Level 3		Level 1		Level 2			Level 3
	Derivative foreign currency forward contracts (see Note 14)		$	—	$	806		$	—	$	—	$	12		$	—
	Interest rate swap contracts (see Note 14)		—		(607		)	—		—		1,087			—
	TOLI policies held by the Rabbi Trust (see Note 13)		—		4,734			—		—		4,625			—
	Deferred Compensation Plan obligations (see Note 13)		—		(4,525		)	—		—		(3,338		)	—
	Fair values of the financial assets and liabilities listed above are determined using inputs that use as their basis readily observable market data that are actively quoted and are validated through external sources, including third-party pricing services and brokers. The foreign currency forward contracts represent gains and losses on derivative contracts, which is the net difference between the U.S. dollar value to be received or paid at the contracts’ settlement date and the U.S. dollar value of the foreign currency to be sold or purchased at the current forward exchange rate. The interest rate swap contract represents gains and losses on the derivative contract, which is the net difference between the fixed interest to be paid and variable interest to be received over the term of the contract based on current market rates. The fair value of the trust owned life insurance (“TOLI”) policies held by the Rabbi Trust is based on the cash-surrender value of the life insurance policies, which are invested primarily in mutual funds and a separately managed fixed income fund. These investments are initially made in the same funds and purchased in substantially the same amounts as the selected investments of participants in the Under Armour, Inc. Deferred Compensation Plan (the “Deferred Compensation Plan”), which represent the underlying liabilities to participants in the Deferred Compensation Plan. Liabilities under the Deferred Compensation Plan are recorded at amounts due to participants, based on the fair value of participants’ selected investments.
	The carrying value of the Company's long term debt approximated its fair value as of December 31, 2014 and 2013. The fair value of the Company's long term debt was estimated based upon quoted prices for similar instruments (Level 2 input).

Provision_For_Income_Taxes

Provision For Income Taxes	12 Months Ended
	Dec. 31, 2014
Taxes Payable [Abstract]
Provision For Income Taxes	Provision for Income Taxes
	Income before income taxes is as follows:
		Year Ended December 31,
	(In thousands)	2014				2013				2012
	Income before income taxes:
	United States	$	269,503			$	196,558			$	155,514
	Foreign	72,707				64,435				47,925
	Total	$	342,210			$	260,993			$	203,439
	The components of the provision for income taxes consisted of the following:
		Year Ended December 31,
	(In thousands)	2014				2013				2012
	Current
	Federal	$	110,439			$	85,542			$	66,533
	State	24,419				19,130				12,962
	Other foreign countries	16,489				13,295				8,139
		151,347				117,967				87,634
	Deferred
	Federal	(15,368		)		(14,722		)		(9,606		)
	State	(4,073		)		(5,541		)		(3,563		)
	Other foreign countries	2,262				959				196
		(17,179		)		(19,304		)		(12,973		)
	Provision for income taxes	$	134,168			$	98,663			$	74,661
	A reconciliation from the U.S. statutory federal income tax rate to the effective income tax rate is as follows:
		Year Ended December 31,
		2014			2013			2012
	U.S. federal statutory income tax rate	35	%		35	%		35	%
	State taxes, net of federal tax impact	3.8			2.4			2.1
	Unrecognized tax benefits	1.9			2.5			2.7
	Nondeductible expenses	1			1.1			0.6
	Foreign rate differential	(4.5	)		(4.8	)		(4.9	)
	Foreign valuation allowance	2.5			1.5			0.8
	Other	(0.5	)		0.1			0.4
	Effective income tax rate	39.2	%		37.8	%		36.7	%
	The increase in the 2014 full year effective income tax rate, as compared to 2013, is primarily due to increased foreign investments driving a lower proportion of foreign taxable income in 2014 and state tax credits received in 2013.
	Deferred tax assets and liabilities consisted of the following:
			December 31,
	(In thousands)		2014				2013
	Deferred tax asset
	Stock-based compensation		$	35,161			$	25,472
	Allowance for doubtful accounts and other reserves		24,774				16,262
	Foreign net operating loss carryforward		16,302				13,829
	Accrued expenses		11,398				3,403
	Deferred rent		11,005				8,980
	Inventory obsolescence reserves		8,198				6,269
	Tax basis inventory adjustment		5,845				5,633
	Foreign tax credits		5,131				3,807
	U. S. net operating loss carryforward		4,733				10,119
	State tax credits, net of federal tax impact		4,245				5,342
	Deferred compensation		1,858				1,372
	Other		4,592				5,889
	Total deferred tax assets		133,242				106,377
	Less: valuation allowance		(15,550		)		(8,091		)
	Total net deferred tax assets		117,692				98,286
	Deferred tax liability
	Property, plant and equipment		(17,638		)		(13,375		)
	Intangible assets		(7,010		)		(8,627		)
	Prepaid expenses		(6,424		)		(6,380		)
	Other		(612		)		(447		)
	Total deferred tax liabilities		(31,684		)		(28,829		)
	Total deferred tax assets, net		$	86,008			$	69,457
	In connection with the Company's acquisition of MapMyFitness (see Note 3), the Company acquired $10.5 million in deferred tax assets associated with approximately $42.5 million in federal and state net operating loss (“NOLs”) carryforwards. The acquisition resulted in a “change of ownership” within the meaning of Section 382 of the Internal Revenue Code, and, as a result, such NOLs are subject to an annual limitation.
	As of December 31, 2014, the Company had $4.7 million in deferred tax assets associated with approximately $23.1 million in federal and state net operating losses from the acquisition of MapMyFitness remaining, which will expire beginning 2029 through 2033. Based upon the historical taxable income and projections of future taxable income over periods in which these NOLs will be deductible, the Company believes that it is more likely than not that the Company will be able to fully utilize these NOLs before the carry-forward periods expire beginning 2029 through 2033, and therefore a valuation allowance is not required.
	As of December 31, 2014, the Company had $16.3 million in deferred tax assets associated with approximately $62.0 million in foreign net operating loss carryforwards, which will expire beginning 2016 through 2020. As of December 31, 2014, the Company believes certain deferred tax assets associated with foreign net operating loss carryforwards will expire unused based on the Company's projections. Therefore, a valuation allowance of $6.1 million was recorded against the Company's net deferred tax assets in 2014.
	As of December 31, 2014, the Company had $5.1 million in deferred tax assets associated with foreign tax credits. As of December 31, 2014 the Company believes that a portion of the foreign taxes paid would not be creditable against its future income taxes. Therefore, a valuation allowance of $1.3 million was recorded against the Company's net deferred tax assets in 2014.
As of December 31, 2014, approximately $129.2 million of cash and cash equivalents was held by the Company's non-U.S. subsidiaries whose cumulative undistributed earnings total $176.8 million. Withholding and U.S. taxes have not been provided on the undistributed earnings as the earnings are being permanently reinvested in its non-U.S. subsidiaries. Determining the tax liability that would arise if these earnings were repatriated is not practical.
We utilize the “with and without” method for intraperiod allocation of income tax provisions.  Certain tax benefits associated with the Company’s stock-based compensation arrangements are recorded directly to Stockholders’ equity including benefit from excess tax deductions.
As of December 31, 2014 and 2013, the total liability for unrecognized tax benefits, including related interest and penalties, was approximately $31.3 million and $24.1 million, respectively. The following table represents a reconciliation of the Company's total unrecognized tax benefits balances, excluding interest and penalties, for the years ended December 31, 2014, 2013 and 2012:
		Year Ended December 31,
(In thousands)		2014				2013				2012
Beginning of year		$	21,712			$	15,297			$	9,783
Increases as a result of tax positions taken in a prior period		250				—				—
Decreases as a result of tax positions taken in a prior period		—				—				—
Increases as a result of tax positions taken during the current period		8,947				7,526				5,702
Decreases as a result of tax positions taken during the current period		—				—				—
Decreases as a result of settlements during the current period		—				—				—
Reductions as a result of a lapse of statute of limitations during the current period		(2,556		)		(1,111		)		(188		)
End of year		$	28,353			$	21,712			$	15,297
As of December 31, 2014, $26.3 million of unrecognized tax benefits, excluding interest and penalties, would impact the Company's effective tax rate if recognized.
As of December 31, 2014, 2013 and 2012, the liability for unrecognized tax benefits included $3.0 million, $2.4 million and $1.8 million, respectively, for the accrual of interest and penalties. For each of the years ended December 31, 2014, 2013 and 2012, the Company recorded $1.2 million, $1.0 million and $0.7 million, respectively, for the accrual of interest and penalties in its consolidated statements of income. The Company recognizes accrued interest and penalties related to unrecognized tax benefits in the provision for income taxes on the consolidated statements of income.
The Company files income tax returns in the U.S. federal jurisdiction and various state and foreign jurisdictions.  The Company is currently under audit by the Internal Revenue Service for the 2011 tax year and by the Canada Revenue Authority for the 2011 through 2012 tax years. The majority of the Company's returns for years before 2011 are no longer subject to U.S. federal, state and local or foreign income tax examinations by tax authorities
The total amount of unrecognized tax benefits relating to the Company's tax positions is subject to change based on future events including, but not limited to, the settlements of ongoing tax audits and assessments and the expiration of applicable statutes of limitations. Although the outcomes and timing of such events are highly uncertain, the Company does not anticipate that the balance of gross unrecognized tax benefits, excluding interest and penalties, will change significantly during the next twelve months. However, changes in the occurrence, expected outcomes, and timing of such events could cause the Company's current estimates to change materially in the future.

Earnings_per_Share

Earnings per Share	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
Earnings per Share	Earnings per Share
	The calculation of earnings per share for common stock shown below excludes the income attributable to outstanding restricted stock awards from the numerator and excludes the impact of these awards from the denominator. The following is a reconciliation of basic earnings per share to diluted earnings per share:
		Year Ended December 31,
	(In thousands, except per share amounts)	2014		2013		2012
	Numerator
	Net income	$	208,042	$	162,330	$	128,778
	Denominator
	Weighted average common shares outstanding	213,227		210,696		208,686
	Effect of dilutive securities	6,153		5,262		4,074
	Weighted average common shares and dilutive securities outstanding	219,380		215,958		212,760
	Earnings per share—basic	$	0.98	$	0.77	$	0.62
	Earnings per share—diluted	$	0.95	$	0.75	$	0.61
	Effects of potentially dilutive securities are presented only in periods in which they are dilutive. Stock options, restricted stock units and warrants representing 22.6 thousand, 116.9 thousand and 208.9 thousand shares of common stock were outstanding for the years ended December 31, 2014, 2013 and 2012, respectively, but were excluded from the computation of diluted earnings per share because their effect would be anti-dilutive.

StockBased_Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2014
Share-based Compensation, Allocation and Classification in Financial Statements [Abstract]
Stock-Based Compensation	Stock-Based Compensation
	Stock Compensation Plans
	The Under Armour, Inc. Amended and Restated 2005 Omnibus Long-Term Incentive Plan (the “2005 Plan”) provides for the issuance of stock options, restricted stock, restricted stock units and other equity awards to officers, directors, key employees and other persons. Stock options and restricted stock and restricted stock unit awards under the 2005 Plan generally vest ratably over a two to four year period. The contractual term for stock options is generally ten years from the date of grant. The Company generally receives a tax deduction for any ordinary income recognized by a participant in respect to an award under the 2005 Plan. The 2005 Plan terminates in 2015. As of December 31, 2014, 19.3 million shares are available for future grants of awards under the 2005 Plan.
	Total stock-based compensation expense for the years ended December 31, 2014, 2013 and 2012 was $50.8 million, $43.2 million and $19.8 million, respectively. As of December 31, 2014, the Company had $28.6 million of unrecognized compensation expense expected to be recognized over a weighted average period of 1.0 year. This unrecognized compensation expense does not include any expense related to performance-based restricted stock units for which the performance targets have not been achieved as of December 31, 2014. Refer to “Restricted Stock and Restricted Stock Units” below for further information on these awards.
	Employee Stock Purchase Plan
	The Company’s Employee Stock Purchase Plan (the “ESPP”) allows for the purchase of Class A Common Stock by all eligible employees at a 15% discount from fair market value subject to certain limits as defined in the ESPP. As of December 31, 2014, 2.8 million shares are available for future purchases under the ESPP. During the years ended December 31, 2014, 2013 and 2012, 87.6 thousand, 108.4 thousand and 113.8 thousand shares were purchased under the ESPP, respectively.
	Non-Employee Director Compensation Plan and Deferred Stock Unit Plan
	The Company’s Non-Employee Director Compensation Plan (the “Director Compensation Plan”) provides for cash compensation and equity awards to non-employee directors of the Company under the 2005 Plan. Non-employee directors have the option to defer the value of their annual cash retainers as deferred stock units in accordance with the Under Armour, Inc. Non-Employee Deferred Stock Unit Plan (the “DSU Plan”). Each new non-employee director receives an award of restricted stock units upon the initial election to the Board of Directors, with the units covering stock valued at $100.0 thousand on the grant date and vesting in three equal annual installments. In addition, each non-employee director receives, following each annual stockholders’ meeting, a grant under the 2005 Plan of restricted stock units covering stock valued at $75.0 thousand on the grant date. Beginning in 2015, this annual grant is increasing from $75.0 thousand to $125.0 thousand. Each award vests 100% on the date of the next annual stockholders’ meeting following the grant date.
	The receipt of the shares otherwise deliverable upon vesting of the restricted stock units automatically defers into deferred stock units under the DSU Plan. Under the DSU Plan each deferred stock unit represents the Company’s obligation to issue one share of the Company’s Class A Common Stock with the shares delivered six months following the termination of the director’s service.
	Stock Options
	The weighted average fair value of a stock option granted for the year ended December 31, 2013 was $12.91. The fair value of each stock option granted is estimated on the date of grant using the Black-Scholes option-pricing model with the following weighted average assumptions:
		Year Ended December 31,
		2013
	Risk-free interest rate	1.2	%
	Average expected life in years	6.25
	Expected volatility	55.4	%
	Expected dividend yield	—	%
	There were no stock options granted during the years ended December 31, 2014 and December 31, 2012.
	A summary of the Company’s stock options as of December 31, 2014, 2013 and 2012, and changes during the years then ended is presented below:
	(In thousands, except per share amounts)	Year Ended December 31,
		2014					2013						2012
		Number		Weighted			Number		Weighted				Number			Weighted
		of Stock		Average			of Stock		Average				of Stock			Average
		Options		Exercise			Options		Exercise				Options			Exercise
				Price					Price							Price
	Outstanding, beginning of year	4,272		$	8.11		6,298		$	7.66			9,616			$	7
	Granted, at fair market value	—		—			20		24.35				—			—
	Exercised	(1,454	)	7.74			(1,822	)	6.68				(2,436	)		5.09
	Expired	—		—			—		—				—			—
	Forfeited	(7	)	16.46			(224	)	8.41				(882	)		7.6
	Outstanding, end of year	2,811		$	8.28		4,272		$	8.11			6,298			$	7.66
	Options exercisable, end of year	2,707		$	7.87		2,346		$	7.8			1,936			$	6.55
	The intrinsic value of stock options exercised during the years ended December 31, 2014, 2013 and 2012 was $73.0 million, $44.1 million and $44.5 million, respectively.
	The following table summarizes information about stock options outstanding and exercisable as of December 31, 2014:
	(In thousands, except per share amounts)
	Options Outstanding								Options Exercisable
	Number of	Weighted			Weighted	Total			Number of		Weighted				Weighted		Total
	Underlying	Average			Average	Intrinsic			Underlying		Average				Average		Intrinsic
	Shares	Exercise			Remaining	Value			Shares		Exercise				Remaining		Value
		Price Per			Contractual						Price Per				Contractual
		Share			Life (Years)						Share				Life (Years)
	2,811	$	8.28		5.01	$	167,623		2,707		$	7.87			4.94		$	162,518
	Restricted Stock and Restricted Stock Units
	A summary of the Company’s restricted stock and restricted stock units as of December 31, 2014, 2013 and 2012, and changes during the years then ended is presented below:
		Year Ended December 31,
	(In thousands, except per share amounts)	2014					2013						2012
		Number		Weighted			Number		Weighted				Number			Weighted
		of		Average			of		Average				of			Average
		Restricted		Fair Value			Restricted		Fair Value				Restricted			Fair Value
		Shares					Shares						Shares
	Outstanding, beginning of year	5,244		$	22.19		4,514		$	19.51			3,292			$	14.56
	Granted	1,061		54.17			1,682		26.35				2,658			22.92
	Forfeited	(958	)	20.98			(410	)	17.37				(758	)		16.73
	Vested	(837	)	19.49			(542	)	16.76				(678	)		11.66
	Outstanding, end of year	4,510		$	30.42		5,244		$	22.19			4,514			$	19.51
	Included in the table above are 1.0 million, 1.4 million and 2.0 million performance-based restricted stock units awarded to certain executives and key employees under the 2005 Plan during the years ended December 31, 2014, 2013 and 2012, respectively. These performance-based restricted stock units have a weighted average fair value of $30.30 and have vesting that is tied to the achievement of certain combined annual operating income targets.
	During the year ended December 31, 2014, the Company deemed the achievement of certain operating income targets probable for the awards granted in 2014, 2013 and 2012, and recorded $38.4 million for a portion of these awards, including cumulative adjustments of $6.6 million during the three months ended March 31, 2014 and $3.8 million during the three months ended September 30, 2014. During the year ended December 31, 2013, the Company deemed the achievement of certain operating targets probable for the awards granted in 2013, 2012 and 2011, and recorded $30.8 million for a portion of these awards, including cumulative adjustments of $9.0 million during the three months ended March 31, 2013 and $11.3 million during the three months ended December 31, 2013. During the year ended December 31, 2012, the Company deemed the achievement of certain operating income targets probable for the awards granted in 2011, and recorded $4.1 million for a portion of these awards, including a cumulative adjustment of $2.4 million during the three months ended March 31, 2012. The Company will assess the probability of the achievement of the operating income targets at the end of each reporting period. If it becomes probable that the remaining performance targets related to these performance-based restricted stock units will be achieved, a cumulative adjustment will be recorded as if ratable stock-based compensation expense had been recorded since the grant date. Additional stock based compensation of up to $2.7 million would have been recorded through December 31, 2014 for all performance-based restricted stock units had the full achievement of these operating income targets been deemed probable.
	Warrants
	In 2006, the Company issued fully vested and non-forfeitable warrants to purchase 1.9 million shares of the Company’s Class A Common Stock to NFL Properties as partial consideration for footwear promotional rights which were recorded as an intangible asset. With the assistance of an independent third party valuation firm, the Company assessed the fair value of the warrants using various fair value models. Using these measures, the Company concluded that the fair value of the warrants was $8.5 million. The warrants have a term of 12 years from the date of issuance and an exercise price of $9.25 per share, which is the adjusted closing price of the Company’s Class A Common Stock on the date of issuance. As of December 31, 2014, all outstanding warrants were exercisable, and no warrants were exercised.

Other_Employee_Benefits

Other Employee Benefits	12 Months Ended
	Dec. 31, 2014
Compensation Related Costs [Abstract]
Other Employee Benefits	Other Employee Benefits
	The Company offers a 401(k) Deferred Compensation Plan for the benefit of eligible employees. Employee contributions are voluntary and subject to Internal Revenue Service limitations. The Company matches a portion of the participant’s contribution and recorded expense of $4.9 million, $2.7 million and $2.3 million for the years ended December 31, 2014, 2013 and 2012, respectively. Shares of the Company’s Class A Common Stock are not an investment option in this plan.
	In addition, the Company offers the Under Armour, Inc. Deferred Compensation Plan which allows a select group of management or highly compensated employees, as approved by the Compensation Committee, to make an annual base salary and/or bonus deferral for each year. As of December 31, 2014 and 2013, the Deferred Compensation Plan obligations were $4.5 million and $3.3 million, respectively, and were included in other long term liabilities on the consolidated balance sheets.
	The Company established the Rabbi Trust to fund obligations to participants in the Deferred Compensation Plan. As of December 31, 2014 and 2013, the assets held in the Rabbi Trust were TOLI policies with cash-surrender values of $4.7 million and $4.6 million, respectively. These assets are consolidated and are included in other long term assets on the consolidated balance sheet. Refer to Note 9 for a discussion of the fair value measurements of the assets held in the Rabbi Trust and the Deferred Compensation Plan obligations.

Risk_Management_and_Derivative

Risk Management and Derivatives	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
Foreign Currency Risk Management and Derivatives	Risk Management and Derivatives
	Foreign Currency Risk Management
	The Company is exposed to gains and losses resulting from fluctuations in foreign currency exchange rates relating to transactions generated by its international subsidiaries in currencies other than their local currencies. These gains and losses are primarily driven by intercompany transactions and inventory purchases denominated in currencies other than the functional currency of the purchasing entity. From time to time, the Company may elect to enter into foreign currency forward contracts to reduce the risk associated with foreign currency exchange rate fluctuations on intercompany transactions and projected inventory purchases for its international subsidiaries. As the Company expands its international business, it may expand the current hedging program to include additional currency pairs and instruments.
	As of December 31, 2014, the aggregate notional value of our outstanding foreign currency forward contracts was $123.3 million, which was comprised of Canadian Dollar/U.S. Dollar, Euro/U.S. Dollar, Yen/Euro, Mexican Peso/Euro and Pound Sterling/Euro currency pairs with contract maturities ranging from one to eleven months. The majority of the Company's foreign currency forward contracts are not designated as cash flow hedges, and accordingly, changes in their fair value are recorded in earnings. During 2014, the Company began entering into foreign currency forward contracts designated as cash flow hedges. For foreign currency forward contracts designated as cash flow hedges, changes in fair value, excluding any ineffective portion, are recorded in other comprehensive income until net income is affected by the variability in cash flows of the hedged transaction. The effective portion is generally released to net income after the maturity of the related derivative and is classified in the same manner as the underlying exposure. During the year ended December 31, 2014, the Company reclassified $0.4 million from other comprehensive income to cost of goods sold related to foreign currency forward contracts designated as cash flow hedges. The fair values of the Company’s foreign currency forward contracts were assets of $806.0 thousand and $12.1 thousand as of December 31, 2014 and 2013, respectively, and were included in prepaid expenses and other current assets on the consolidated balance sheet. Refer to Note 9 for a discussion of the fair value measurements. Included in other expense, net were the following amounts related to changes in foreign currency exchange rates and derivative foreign currency forward contracts:
	(In thousands)	Year Ended December 31,
		2014			2013			2012
	Unrealized foreign currency exchange rate gains (losses)	$	(11,739	)	$	(1,905	)	$	2,464
	Realized foreign currency exchange rate gains (losses)	2,247			477			(182		)
	Unrealized derivative gains (losses)	1			13			675
	Realized derivative gains (losses)	3,081			243			(3,030		)
	Interest Rate Risk Management
	In order to maintain liquidity and fund business operations, the Company enters into long term debt arrangements with various lenders which bear a range of fixed and variable rates of interest. The nature and amount of the Company's long-term debt can be expected to vary as a result of future business requirements, market conditions and other factors. The Company may elect to enter into interest rate swap contracts to reduce the impact associated with interest rate fluctuations. The Company utilizes interest rate swap contracts to convert a portion of variable rate debt to fixed rate debt. The contracts pay fixed and receive variable rates of interest. The interest rate swap contracts are accounted for as cash flow hedges and accordingly, the effective portion of the changes in their fair value are recorded in other comprehensive income and reclassified into interest expense over the life of the underlying debt obligation.
	As of December 31, 2014, the aggregate notional value of our outstanding interest rate swap contracts was $188.1 million. During the years ended December 31, 2014 and 2013, the Company recorded a $1.7 million and $0.3 million increase in interest expense, respectively, representing the effective portion of the contracts reclassified from accumulated other comprehensive income. The fair value of the interest rate swap contracts was a liability of $0.6 million as of December 31, 2014, and was included in other long term liabilities on the consolidated balance sheet. The fair value of the interest rate swap contract was an asset of $1.1 million as of December 31, 2013 and was included in other long term assets on the consolidated balance sheet.
	The Company enters into derivative contracts with major financial institutions with investment grade credit ratings and is exposed to credit losses in the event of non-performance by these financial institutions. This credit risk is generally limited to the unrealized gains in the foreign currency forward contracts. However, the Company monitors the credit quality of these financial institutions and considers the risk of counterparty default to be minimal.

Related_Party_Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2014
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions
	The Company has agreements to license software systems with a software company whose CEO is a director of the Company. During the years ended December 31, 2014, 2013 and 2012, the Company paid $5.2 million, $3.7 million and $1.9 million, respectively, in licensing fees and related support services to this company. There were no amounts payable to this related party as of December 31, 2014 and 2013.
	The Company has an operating lease agreement with an entity controlled by the Company’s CEO to lease an aircraft for business purposes. The Company paid $1.8 million, $1.0 million and $0.8 million in lease payments to the entity for its use of the aircraft during the years ended December 31, 2014, 2013 and 2012, respectively. No amounts were payable to this related party as of December 31, 2014 and 2013. The Company determined the lease payments were at or below fair market lease rates.
	During 2014, the Company entered into a lease agreement with an entity controlled by the Company’s CEO to lease office space for business purposes. The lease has a 10 year term beginning in 2016 and lease payments are expected to begin at $1.1 million annually with an annual escalation of 2.0% thereafter. The Company determined the lease payments were at or below fair market lease rates.

Segment_Data_and_Related_Infor

Segment Data and Related Information	12 Months Ended
	Dec. 31, 2014
Segment Data and Related Information	Segment Data and Related Information
	The Company’s operating segments are based on how the Chief Operating Decision Maker (“CODM”) makes decisions about allocating resources and assessing performance. As such, the CODM receives discrete financial information for the Company's principal business by geographic region based on the Company’s strategy to become a global brand. These geographic regions include North America; Latin America; Europe, the Middle East and Africa (“EMEA”); and Asia-Pacific. Each geographic segment operates exclusively in one industry: the development, marketing and distribution of branded performance apparel, footwear and accessories. The CODM also receives discrete financial information for the Company's MapMyFitness business. Due to the insignificance of the EMEA, Latin America, Asia-Pacific and MapMyFitness operating segments, they have been combined into other foreign countries and businesses for disclosure purposes.
	The net revenues and operating income (loss) associated with the Company's segments are summarized in the following tables. Net revenues represent sales to external customers for each segment. In addition to net revenues, operating income (loss) is a primary financial measure used by the Company to evaluate performance of each segment. Intercompany balances were eliminated for separate disclosure and the majority of corporate expenses within North America have not been allocated to other foreign countries and businesses.
	(In thousands)	Year Ended December 31,
		2014			2013			2012
	Net revenues
	North America	$	2,796,390		$	2,193,739		$	1,726,733
	Other foreign countries and businesses	287,980			138,312			108,188
	Total net revenues	$	3,084,370		$	2,332,051		$	1,834,921
	(In thousands)	Year Ended December 31,
		2014			2013			2012
	Operating income (loss)
	North America	$	372,347		$	271,338		$	200,084
	Other foreign countries and businesses	(18,392		)	(6,240		)	8,611
	Total operating income	353,955			265,098			208,695
	Interest expense, net	(5,335		)	(2,933		)	(5,183		)
	Other expense, net	(6,410		)	(1,172		)	(73		)
	Income before income taxes	$	342,210		$	260,993		$	203,439
	Net revenues by product category are as follows:
	(In thousands)	Year Ended December 31,
		2014			2013			2012
	Apparel	$	2,291,520		$	1,762,150		$	1,385,350
	Footwear	430,987			298,825			238,955
	Accessories	275,425			216,098			165,835
	Total net sales	2,997,932			2,277,073			1,790,140
	Licensing and other revenues	86,438			54,978			44,781
	Total net revenues	$	3,084,370		$	2,332,051		$	1,834,921
	As of December 31, 2014 and 2013, the majority of the Company’s long-lived assets were located in the United States. Net revenues in the United States were $2,670.4 million, $2,082.5 million and $1,650.4 million for the years ended December 31, 2014, 2013 and 2012, respectively.

Unaudited_Quarterly_Financial_

Unaudited Quarterly Financial Data	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Data [Abstract]
Unaudited Quarterly Financial Data	Unaudited Quarterly Financial Data
	(In thousands)	Quarter Ended (unaudited)								Year Ended
		March 31,		June 30,		September 30,		December 31,		December 31,
	2014
	Net revenues	$	641,607	$	609,654	$	937,908	$	895,201	$	3,084,370
	Gross profit	300,690		299,952		465,300		446,264		1,512,206
	Income from operations	26,856		34,694		146,106		146,299		353,955
	Net income	13,538		17,690		89,105		87,709		208,042
	Earnings per share-basic	$	0.06	$	0.08	$	0.42	$	0.41	$	0.98
	Earnings per share-diluted	$	0.06	$	0.08	$	0.41	$	0.4	$	0.95
	2013
	Net revenues	$	471,608	$	454,541	$	723,146	$	682,756	$	2,332,051
	Gross profit	216,551		219,631		350,135		350,353		1,136,670
	Income from operations	13,492		32,310		120,829		98,467		265,098
	Net income	7,814		17,566		72,784		64,166		162,330
	Earnings per share-basic	$	0.04	$	0.08	$	0.34	$	0.3	$	0.77
	Earnings per share-diluted	$	0.04	$	0.08	$	0.34	$	0.3	$	0.75

Subsequent_Events

Subsequent Events	12 Months Ended
	Dec. 31, 2014
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events
	Acquisitions
	On January 5, 2015, the Company acquired 100% of the outstanding equity of Endomondo ApS, a Denmark-based connected fitness company for $85 million, subject to adjustment for working capital. In connection with this acquisition, the Company incurred acquisition related expenses of approximately $0.8 million during the year ended December 31, 2014. These expenses were included in selling, general and administrative expenses on the consolidated statements of income. The operating results for this acquisition will be included in the Company’s consolidated statements of income from the date of acquisition. The Company is currently in the process of assessing the fair value of the assets acquired and liabilities assumed, which is expected to be final during the first quarter of 2015.
	On February 3, 2015, the Company entered into an agreement to acquire MyFitnessPal, Inc. ("MyFitnessPal"). The purchase price for the acquisition will be $475 million in cash, which will be adjusted to reflect that the acquisition of MyFitnessPal by the Company at the closing on a debt free basis with MyFitnessPal's transaction expenses borne by the sellers. In addition, the aggregate purchase price payable at the closing is subject to an upward adjustment to reflect the amount of net cash held by MyFitnessPal at closing. The acquisition is currently expected to close during the first quarter of 2015, subject to the satisfaction of customary closing conditions, including among others, regulatory approvals, the continuing accuracy of representations and warranties and the execution of noncompetition agreements by certain key employee stockholders. The acquisition is expected to be funded through a combination of increased term loan borrowings, a draw on the increased revolving credit facility and cash on hand.

Valuation_And_Qualifying_Accou

Valuation And Qualifying Accounts	12 Months Ended
	Dec. 31, 2014
Valuation and Qualifying Accounts [Abstract]
Valuation And Qualifying Accounts	Schedule II
	Valuation and Qualifying Accounts
	(In thousands)
	Description	Balance at		Charged to			Write-Offs			Balance at
		Beginning		Costs and			Net of			End of
		of Year		Expenses			Recoveries			Year
	Allowance for doubtful accounts
	For the year ended December 31, 2014	$	2,938	$	1,028		$	(273	)	$	3,693
	For the year ended December 31, 2013	3,286		210			(558		)	2,938
	For the year ended December 31, 2012	4,070		(108		)	(676		)	3,286
	Sales returns and allowances
	For the year ended December 31, 2014	$	34,102	$	156,791		$	(137,920	)	$	52,973
	For the year ended December 31, 2013	32,919		135,739			(134,556		)	34,102
	For the year ended December 31, 2012	20,600		107,536			(95,217		)	32,919
	Deferred tax asset valuation allowance
	For the year ended December 31, 2014	$	8,091	$	7,581		$	(122	)	$	15,550
	For the year ended December 31, 2013	3,996		4,095			—			8,091
	For the year ended December 31, 2012	1,784		2,855			(643		)	3,996

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
Basis of Presentation and Significant Accounting Policies	Basis of Presentation
	The accompanying consolidated financial statements include the accounts of Under Armour, Inc. and its wholly owned subsidiaries (the “Company”). All intercompany balances and transactions have been eliminated. The accompanying consolidated financial statements were prepared in accordance with accounting principles generally accepted in the United States of America.
	On June 11, 2012 and March 17, 2014 the Board of Directors declared two-for-one stock splits of the Company's Class A and Class B common stock, which were effected in the form of a 100% common stock dividend distributed on July 9, 2012 and April 14, 2014, respectively. Stockholders' equity and all references to share and per share amounts in the accompanying consolidated financial statements have been retroactively adjusted to reflect these two-for-one stock splits for all periods presented.
Earnings Per Share, Policy	Earnings per Share
	Basic earnings per common share is computed by dividing net income available to common stockholders for the period by the weighted average number of common shares outstanding during the period. Any stock-based compensation awards that are determined to be participating securities, which are stock-based compensation awards that entitle the holders to receive dividends prior to vesting, are included in the calculation of basic earnings per share using the two class method. Diluted earnings per common share is computed by dividing net income available to common stockholders for the period by the diluted weighted average common shares outstanding during the period. Diluted earnings per share reflects the potential dilution from common shares issuable through stock options, warrants, restricted stock units and other equity awards. Refer to Note 11 for further discussion of earnings per share.
Cost Based Investment	Minority Investment
	The Company holds a minority investment in Dome Corporation (“Dome”), the Company’s Japanese licensee. The Company invested ¥1,140.0 million, or $15.5 million, in exchange for 19.5% common stock ownership in Dome. As of December 31, 2014 and 2013, the carrying value of the Company’s investment was $13.4 million and $15.2 million, respectively, and was included in other long term assets on the consolidated balance sheet. The investment is subject to foreign currency translation rate fluctuations as it is held by the Company’s European subsidiary.
	The Company accounts for its investment in Dome under the cost method given that it does not have the ability to exercise significant influence. Additionally, the Company concluded that no event or change in circumstances occurred during the year ended December 31, 2014 that may have a significant adverse effect on the fair value of the investment.
Advertising Costs, Policy	Advertising Costs
	Advertising costs are charged to selling, general and administrative expenses. Advertising production costs are expensed the first time an advertisement related to such production costs is run. Media (television, print and radio) placement costs are expensed in the month during which the advertisement appears, and costs related to event sponsorships are expensed when the event occurs. In addition, advertising costs include sponsorship expenses. Accounting for sponsorship payments is based upon specific contract provisions and the payments are generally expensed uniformly over the term of the contract after recording expense related to specific performance incentives once they are deemed probable. Advertising expense, including amortization of in-store marketing fixtures and displays, was $333.0 million, $246.5 million and $205.4 million for the years ended December 31, 2014, 2013 and 2012, respectively. At December 31, 2014 and 2013, prepaid advertising costs were $31.1 million and $22.0 million, respectively.
Foreign Currency Transactions and Translations Policy	Foreign Currency Translation and Transactions
	The functional currency for each of the Company’s wholly owned foreign subsidiaries is generally the applicable local currency. The translation of foreign currencies into U.S. dollars is performed for assets and liabilities using current foreign currency exchange rates in effect at the balance sheet date and for revenue and expense accounts using average foreign currency exchange rates during the period. Capital accounts are translated at historical foreign currency exchange rates. Translation gains and losses are included in stockholders’ equity as a component of accumulated other comprehensive income. Adjustments that arise from foreign currency exchange rate changes on transactions, primarily driven by intercompany transactions, denominated in a currency other than the functional currency are included in other expense, net on the consolidated statements of income.
Impairment or Disposal of Long-Lived Assets, Including Intangible Assets, Policy	Goodwill, Intangible Assets and Long-Lived Assets
	Goodwill and intangible assets are recorded at their estimated fair values at the date of acquisition and are allocated to the reporting units that are expected to receive the related benefits. Goodwill and indefinite lived intangible assets are not amortized and are required to be tested for impairment at least annually or sooner whenever events or changes in circumstances indicate that the assets may be impaired. In conducting an annual impairment test, the Company first reviews qualitative factors to determine whether it is more likely than not that the fair value of the reporting unit is less than its carrying amount. If factors indicate that is the case, the Company performs a quantitative assessment over relevant reporting units, analyzing the expected present value of future cash flows and quantify the amount of impairment, if any. The Company performs its annual impairment tests in the fourth quarter of each fiscal year.
	The Company continually evaluates whether events and circumstances have occurred that indicate the remaining estimated useful life of long-lived assets may warrant revision or that the remaining balance may not be recoverable. These factors may include a significant deterioration of operating results, changes in business plans, or changes in anticipated cash flows. When factors indicate that an asset should be evaluated for possible impairment, the Company reviews long-lived assets to assess recoverability from future operations using undiscounted cash flows. If future undiscounted cash flows are less than the carrying value, an impairment is recognized in earnings to the extent that the carrying value exceeds fair value.
Inventory, Policy	Inventories
	Inventories consist primarily of finished goods. Costs of finished goods inventories include all costs incurred to bring inventory to its current condition, including inbound freight, duties and other costs. The Company values its inventory at standard cost which approximates landed cost, using the first-in, first-out method of cost determination. Market value is estimated based upon assumptions made about future demand and retail market conditions. If the Company determines that the estimated market value of its inventory is less than the carrying value of such inventory, it records a charge to cost of goods sold to reflect the lower of cost or market. If actual market conditions are less favorable than those projected by the Company, further adjustments may be required that would increase the cost of goods sold in the period in which such a determination was made.
Concentration of Credit Risk	Concentration of Credit Risk
	Financial instruments that subject the Company to significant concentration of credit risk consist primarily of accounts receivable. The majority of the Company’s accounts receivable is due from large sporting goods retailers. Credit is extended based on an evaluation of the customer’s financial condition and collateral is not required. The Company had two customers in North America that individually accounted for 23.4% and 11.1% of accounts receivable as of December 31, 2014. The Company's largest customer accounted for 14.4%, 16.6% and 16.6% of net revenues for the years ended December 31, 2014, 2013 and 2012, respectively.
Allowance For Doubtful Accounts	Allowance for Doubtful Accounts
	The Company makes ongoing estimates relating to the collectability of accounts receivable and maintains an allowance for estimated losses resulting from the inability of its customers to make required payments. In determining the amount of the reserve, the Company considers historical levels of credit losses and significant economic developments within the retail environment that could impact the ability of its customers to pay outstanding balances and makes judgments about the creditworthiness of significant customers based on ongoing credit evaluations. Because the Company cannot predict future changes in the financial stability of its customers, actual future losses from uncollectible accounts may differ from estimates. If the financial condition of customers were to deteriorate, resulting in their inability to make payments, a larger reserve might be required. In the event the Company determines a smaller or larger reserve is appropriate, it would record a benefit or charge to selling, general and administrative expense in the period in which such a determination was made. As of December 31, 2014 and 2013, the allowance for doubtful accounts was $3.7 million and $2.9 million, respectively.
Shipping and Handling Costs	Shipping and Handling Costs
	The Company charges certain customers shipping and handling fees. These fees are recorded in net revenues. The Company includes the majority of outbound handling costs as a component of selling, general and administrative expenses. Outbound handling costs include costs associated with preparing goods to ship to customers and certain costs to operate the Company’s distribution facilities. These costs, included within selling, general and administrative expenses, were $55.3 million, $46.1 million and $34.8 million for the years ended December 31, 2014, 2013 and 2012, respectively. The Company includes outbound freight costs associated with shipping goods to customers as a component of cost of goods sold.
Management Estimates	Management Estimates
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from these estimates.
Cash and Cash Equivalents, Policy	Cash and Cash Equivalents
	The Company considers all highly liquid investments with an original maturity of three months or less at date of inception to be cash and cash equivalents. Included in interest expense, net for the years ended December 31, 2014, 2013 and 2012 was interest income of $192.0 thousand, $23.7 thousand and $25.2 thousand, respectively, related to cash and cash equivalents.
Income Tax, Policy	Income Taxes
	Income taxes are accounted for under the asset and liability method. Deferred income tax assets and liabilities are established for temporary differences between the financial reporting basis and the tax basis of the Company’s assets and liabilities at tax rates expected to be in effect when such assets or liabilities are realized or settled. Deferred income tax assets are reduced by valuation allowances when necessary.
	Assessing whether deferred tax assets are realizable requires significant judgment. The Company considers all available positive and negative evidence, including historical operating performance and expectations of future operating performance. The ultimate realization of deferred tax assets is often dependent upon future taxable income and therefore can be uncertain. To the extent the Company believes it is more likely than not that all or some portion of the asset will not be realized, valuation allowances are established against the Company’s deferred tax assets, which increase income tax expense in the period when such a determination is made.
	Income taxes include the largest amount of tax benefit for an uncertain tax position that is more likely than not to be sustained upon audit based on the technical merits of the tax position. Settlements with tax authorities, the expiration of statutes of limitations for particular tax positions, or obtaining new information on particular tax positions may cause a change to the effective tax rate. The Company recognizes accrued interest and penalties related to unrecognized tax benefits in the provision for income taxes on the consolidated statements of income.
Property, Plant and Equipment, Policy	Property and Equipment
	Property and equipment are stated at cost, including the cost of internal labor for software customized for internal use, less accumulated depreciation and amortization. Property and equipment is depreciated using the straight-line method over the estimated useful lives of the assets: 3 to 10 years for furniture, office equipment, software and plant equipment and 10 to 35 years for site improvements, buildings and building equipment. Leasehold and tenant improvements are amortized over the shorter of the lease term or the estimated useful lives of the assets. The cost of in-store apparel and footwear fixtures and displays are capitalized, included in furniture, fixtures and displays, and depreciated over 3 years. The Company periodically reviews assets’ estimated useful lives based upon actual experience and expected future utilization. A change in useful life is treated as a change in accounting estimate and is applied prospectively.
	The Company capitalizes the cost of interest for long term property and equipment projects based on the Company’s weighted average borrowing rates in place while the projects are in progress. Capitalized interest was $0.4 million and $0.4 million as of December 31, 2014 and 2013, respectively.
	Upon retirement or disposition of property and equipment, the cost and accumulated depreciation are removed from the accounts and any resulting gain or loss is reflected in selling, general and administrative expenses for that period. Major additions and betterments are capitalized to the asset accounts while maintenance and repairs, which do not improve or extend the lives of assets, are expensed as incurred.
Accrued Expenses	Accrued Expenses
	At December 31, 2014, accrued expenses primarily included $61.4 million and $14.0 million of accrued compensation and benefits and marketing expenses, respectively. At December 31, 2013, accrued expenses primarily included $56.7 million and $11.9 million of accrued compensation and benefits and marketing expenses, respectively.
Derivatives, Policy	Derivatives and Hedging Activities
	The Company uses derivative financial instruments in the form of foreign currency forward and interest rate swap contracts to minimize the risk associated with foreign currency exchange rate and interest rate fluctuations. The Company accounts for derivative financial instruments pursuant to applicable accounting guidance. This guidance establishes accounting and reporting standards for derivative financial instruments and requires all derivatives to be recognized as either assets or liabilities on the balance sheet and to be measured at fair value. Unrealized derivative gain positions are recorded as other current assets or other long term assets, and unrealized derivative loss positions are recorded as accrued expenses or other long term liabilities, depending on the derivative financial instrument’s maturity date.
	Currently, the majority of the Company’s foreign currency forward contracts are not designated as cash flow hedges, and accordingly, changes in their fair value are included in other expense, net on the consolidated statements of income. During 2014, the Company began entering into foreign currency forward contracts designated as cash flow hedges, and consequently, changes in fair value, excluding any ineffective portion, are recorded in other comprehensive income until net income is affected by the variability in cash flows of the hedged transaction. The effective portion is generally released to net income after the maturity of the related derivative and is classified in the same manner as the underlying exposure. Additionally, the Company has designated its interest rate swap contract as a cash flow hedge and accordingly, the effective portion of changes in fair value are recorded in other comprehensive income and reclassified into interest expense over the life of the underlying debt obligation. The ineffective portion, if any, is recognized in current period earnings. The Company does not enter into derivative financial instruments for speculative or trading purposes.
Revenue Recognition, Policy	Revenue Recognition
	The Company recognizes revenue pursuant to applicable accounting standards. Net revenues consist of both net sales and license and other revenues. Net sales are recognized upon transfer of ownership, including passage of title to the customer and transfer of risk of loss related to those goods. Transfer of title and risk of loss is based upon shipment under free on board shipping point for most goods or upon receipt by the customer depending on the country of the sale and the agreement with the customer. In some instances, transfer of title and risk of loss takes place at the point of sale, for example, at the Company’s brand and factory house stores. The Company may also ship product directly from its supplier to the customer and recognize revenue when the product is delivered to and accepted by the customer. License and other revenues are primarily recognized based upon shipment of licensed products sold by the Company’s licensees. Sales taxes imposed on the Company’s revenues from product sales are presented on a net basis on the consolidated statements of income and therefore do not impact net revenues or costs of goods sold.
	The Company records reductions to revenue for estimated customer returns, allowances, markdowns and discounts. The Company bases its estimates on historical rates of customer returns and allowances as well as the specific identification of outstanding returns, markdowns and allowances that have not yet been received by the Company. The actual amount of customer returns and allowances, which is inherently uncertain, may differ from the Company’s estimates. If the Company determines that actual or expected returns or allowances are significantly higher or lower than the reserves it established, it would record a reduction or increase, as appropriate, to net sales in the period in which it makes such a determination. Provisions for customer specific discounts are based on contractual obligations with certain major customers. Reserves for returns, allowances, markdowns and discounts are recorded as an offset to accounts receivable as settlements are made through offsets to outstanding customer invoices. As of December 31, 2014 and 2013, there were $68.9 million and $43.8 million, respectively, in reserves for customer returns, allowances, markdowns and discounts.
Share-based Compensation, Option and Incentive Plans Policy	Stock-Based Compensation
	The Company accounts for stock-based compensation in accordance with accounting guidance that requires all stock-based compensation awards granted to employees and directors to be measured at fair value and recognized as an expense in the financial statements. In addition, this guidance requires that excess tax benefits related to stock-based compensation awards be reflected as financing cash flows.
	The Company uses the Black-Scholes option-pricing model to estimate the fair market value of stock-based compensation awards. The Company uses the “simplified method” to estimate the expected life of options, as permitted by accounting guidance. The “simplified method” calculates the expected life of a stock option equal to the time from grant to the midpoint between the vesting date and contractual term, taking into account all vesting tranches. The risk free interest rate is based on the yield for the U.S. Treasury bill with a maturity equal to the expected life of the stock option. Expected volatility is based on the Company's historical average. Compensation expense is recognized net of forfeitures on a straight-line basis over the total vesting period, which is the implied requisite service period. Compensation expense for performance-based awards is recorded over the implied requisite service period when achievement of the performance target is deemed probable. The forfeiture rate is estimated at the date of grant based on historical rates.
	The Company issues new shares of Class A Common Stock upon exercise of stock options, grant of restricted stock or share unit conversion. Refer to Note 12 for further details on stock-based compensation.
Fair Value of Financial Instruments, Policy	Fair Value of Financial Instruments
	The carrying amounts shown for the Company’s cash and cash equivalents, accounts receivable and accounts payable approximate fair value because of the short term maturity of those instruments. The fair value of the long term debt approximates its carrying value based on the variable nature of interest rates and current market rates available to the Company. The fair value of foreign currency forward contracts is based on the net difference between the U.S. dollars to be received or paid at the contracts’ settlement date and the U.S. dollar value of the foreign currency to be sold or purchased at the current forward exchange rate. The fair value of the interest rate swap contract is based on the net difference between the fixed interest to be paid and variable interest to be received over the term of the contract based on current market rates.
New Accounting Pronouncements, Policy	Recently Issued Accounting Standards
	In May 2014, the Financial Accounting Standards Board (“FASB”) issued an Accounting Standards Update which supersedes the most current revenue recognition requirements. The new revenue recognition standard requires entities to recognize revenue in a way that depicts the transfer of goods or services to customers in an amount that reflects the consideration which the entity expects to be entitled to in exchange for those goods or services. This guidance is effective for annual and interim reporting periods beginning after December 15, 2016, with early adoption not permitted. The Company is currently evaluating the standard to determine the impact of its adoption on the Company's consolidated financial statements.
	In January 2015, the FASB issued an Accounting Standards Update which eliminates from GAAP the concept of extraordinary items and the need to separately classify, present, and disclose extraordinary events and transactions. This guidance is effective for annual and interim reporting periods beginning after December 15, 2015, with early adoption permitted provided that the guidance is applied from the beginning of the fiscal year of adoption. The adoption of this pronouncement is not expected to impact the Company's consolidated financial statements.
	Recently Adopted Accounting Standards
	In July 2013, the FASB issued an Accounting Standards Update which requires that an unrecognized tax benefit, or a portion of an unrecognized tax benefit, should be presented in the financial statements as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward, with certain exceptions. This guidance is effective for annual and interim reporting periods beginning after December 15, 2013. The adoption of this pronouncement did not have a material impact on the Company's consolidated financial statements.
	In February 2013, the FASB issued an Accounting Standards Update which requires companies to present either in a single note or parenthetically on the face of the financial statements, the effect of significant amounts reclassified from each component of accumulated other comprehensive income based on its source and the income statement line items affected by the reclassification. This guidance is effective for annual and interim reporting periods beginning after December 15, 2012. The adoption of this pronouncement did not have a material impact on the Company's consolidated financial statements.

Property_And_Equipment_Net_Tab

Property And Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Components of Property and Equipment	Property and equipment consisted of the following:
		December 31,
	(In thousands)	2014			2013
	Leasehold and tenant improvements	$	128,088		$	97,776
	Furniture, fixtures and displays	80,035			68,045
	Buildings	46,419			45,903
	Software	67,506			51,984
	Office equipment	51,531			39,551
	Plant equipment	70,317			45,509
	Land	17,628			17,628
	Construction in progress	57,677			28,471
	Other	3,175			1,219
	Subtotal property and equipment	522,376			396,086
	Accumulated depreciation	(216,812		)	(172,134		)
	Property and equipment, net	$	305,564		$	223,952

Goodwill_and_Intangible_Assets1

Goodwill and Intangible Assets, Net (Tables)	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The following table summarizes changes in the carrying amount of the Company’s goodwill by reportable segment as of the periods indicated:
	(In thousands)	North America		Other foreign countries and businesses			Total
	Balance as of December 31, 2013	$	119,799	$	2,445		$	122,244
	Goodwill acquired	—		1,012			1,012
	Balance as of December 31, 2014	$	119,799	$	3,457		$	123,256
Summary Of Intangible Assets	The following table summarizes the Company’s intangible assets as of the periods indicated:
		31-Dec-14							31-Dec-13
	(In thousands)	Gross		Accumulated			Net Carrying		Gross		Accumulated			Net Carrying
		Carrying		Amortization			Amount		Carrying		Amortization			Amount
		Amount							Amount
	Intangible assets subject to amortization:
	Technology	$	12,000	$	(1,907	)	$	10,093	$	12,000	$	(126	)	$	11,874
	Trade name	5,000		(1,353		)	3,647		5,000		(53		)	4,947
	Customer relationships	11,927		(4,692		)	7,235		3,600		(38		)	3,562
	Lease-related intangible assets	3,896		(2,762		)	1,134		3,896		(2,605		)	1,291
	Other	2,196		(893		)	1,303		1,266		(532		)	734
	Total	$	35,019	$	(11,607	)	$	23,412	$	25,762	$	(3,354	)	$	22,408
	Indefinite-lived intangible assets						2,818							1,689
	Intangible assets, net						$	26,230						$	24,097

Credit_Facility_and_Long_Term_1

Credit Facility and Long Term Debt (Tables)	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Scheduled Maturities of Long Term Debt	The following are the scheduled maturities of long term debt as of December 31, 2014:
	(In thousands)
	2015	$	28,951
	2016	27,000
	2017	27,000
	2018	27,000
	2019	138,250
	2020 and thereafter	36,000
	Total scheduled maturities of long term debt	284,201
	Less current maturities of long term debt	(28,951		)
	Long term debt obligations	$	255,250

Commitments_And_Contingencies_

Commitments And Contingencies (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Future Minimum Lease Payments For Non-Cancelable Real Property Operating Leases	The following is a schedule of future minimum lease payments for non-cancelable real property operating leases as of December 31, 2014 as well as significant operating lease agreements entered into during the period after December 31, 2014 through the date of this report:
	(In thousands)
	2015		$	56,452
	2016		57,079
	2017		52,172
	2018		48,345
	2019		44,313
	2020 and thereafter		214,214
	Total future minimum lease payments		$	472,575
Future Minimum Payments Under Sponsorship And Other Marketing Agreements	The following is a schedule of the Company’s future minimum payments under its sponsorship and other marketing agreements as of December 31, 2014, as well as significant sponsorship and other marketing agreements entered into during the period after December 31, 2014 through the date of this report:
	(In thousands)
	2015	$	90,056
	2016	71,654
	2017	56,734
	2018	44,982
	2019	33,155
	2020 and thereafter	96,345
	Total future minimum sponsorship and other marketing payments	$	392,926

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
Financial Assets and (Liabilities) Measured at Fair Value	Financial assets and (liabilities) measured at fair value are set forth in the table below:
		31-Dec-14							31-Dec-13
	(In thousands)	Level 1		Level 2			Level 3		Level 1		Level 2			Level 3
	Derivative foreign currency forward contracts (see Note 14)	$	—	$	806		$	—	$	—	$	12		$	—
	Interest rate swap contracts (see Note 14)	—		(607		)	—		—		1,087			—
	TOLI policies held by the Rabbi Trust (see Note 13)	—		4,734			—		—		4,625			—
	Deferred Compensation Plan obligations (see Note 13)	—		(4,525		)	—		—		(3,338		)	—

Provision_For_Income_Taxes_Tab

Provision For Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Taxes Payable [Abstract]
Income (Loss) Before Income Taxes	Income before income taxes is as follows:
		Year Ended December 31,
	(In thousands)	2014				2013				2012
	Income before income taxes:
	United States	$	269,503			$	196,558			$	155,514
	Foreign	72,707				64,435				47,925
	Total	$	342,210			$	260,993			$	203,439
Components Of The Provision For Income Taxes	The components of the provision for income taxes consisted of the following:
		Year Ended December 31,
	(In thousands)	2014				2013				2012
	Current
	Federal	$	110,439			$	85,542			$	66,533
	State	24,419				19,130				12,962
	Other foreign countries	16,489				13,295				8,139
		151,347				117,967				87,634
	Deferred
	Federal	(15,368		)		(14,722		)		(9,606		)
	State	(4,073		)		(5,541		)		(3,563		)
	Other foreign countries	2,262				959				196
		(17,179		)		(19,304		)		(12,973		)
	Provision for income taxes	$	134,168			$	98,663			$	74,661
Reconciliation From The U.S. Statutory Federal Income Tax Rate To Effective Income Tax Rate	A reconciliation from the U.S. statutory federal income tax rate to the effective income tax rate is as follows:
		Year Ended December 31,
		2014			2013			2012
	U.S. federal statutory income tax rate	35	%		35	%		35	%
	State taxes, net of federal tax impact	3.8			2.4			2.1
	Unrecognized tax benefits	1.9			2.5			2.7
	Nondeductible expenses	1			1.1			0.6
	Foreign rate differential	(4.5	)		(4.8	)		(4.9	)
	Foreign valuation allowance	2.5			1.5			0.8
	Other	(0.5	)		0.1			0.4
	Effective income tax rate	39.2	%		37.8	%		36.7	%
Deferred Tax Assets And Liabilities	Deferred tax assets and liabilities consisted of the following:
			December 31,
	(In thousands)		2014				2013
	Deferred tax asset
	Stock-based compensation		$	35,161			$	25,472
	Allowance for doubtful accounts and other reserves		24,774				16,262
	Foreign net operating loss carryforward		16,302				13,829
	Accrued expenses		11,398				3,403
	Deferred rent		11,005				8,980
	Inventory obsolescence reserves		8,198				6,269
	Tax basis inventory adjustment		5,845				5,633
	Foreign tax credits		5,131				3,807
	U. S. net operating loss carryforward		4,733				10,119
	State tax credits, net of federal tax impact		4,245				5,342
	Deferred compensation		1,858				1,372
	Other		4,592				5,889
	Total deferred tax assets		133,242				106,377
	Less: valuation allowance		(15,550		)		(8,091		)
	Total net deferred tax assets		117,692				98,286
	Deferred tax liability
	Property, plant and equipment		(17,638		)		(13,375		)
	Intangible assets		(7,010		)		(8,627		)
	Prepaid expenses		(6,424		)		(6,380		)
	Other		(612		)		(447		)
	Total deferred tax liabilities		(31,684		)		(28,829		)
	Total deferred tax assets, net		$	86,008			$	69,457
Unrecognized Tax Benefits Balances	The following table represents a reconciliation of the Company's total unrecognized tax benefits balances, excluding interest and penalties, for the years ended December 31, 2014, 2013 and 2012:
			Year Ended December 31,
	(In thousands)		2014				2013				2012
	Beginning of year		$	21,712			$	15,297			$	9,783
	Increases as a result of tax positions taken in a prior period		250				—				—
	Decreases as a result of tax positions taken in a prior period		—				—				—
	Increases as a result of tax positions taken during the current period		8,947				7,526				5,702
	Decreases as a result of tax positions taken during the current period		—				—				—
	Decreases as a result of settlements during the current period		—				—				—
	Reductions as a result of a lapse of statute of limitations during the current period		(2,556		)		(1,111		)		(188		)
	End of year		$	28,353			$	21,712			$	15,297

Earnings_per_Share_Tables

Earnings per Share (Tables)	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
Schedule of Reconciliation of Basic Earnings per Share to Diluted Earnings per Share	The following is a reconciliation of basic earnings per share to diluted earnings per share:
		Year Ended December 31,
	(In thousands, except per share amounts)	2014		2013		2012
	Numerator
	Net income	$	208,042	$	162,330	$	128,778
	Denominator
	Weighted average common shares outstanding	213,227		210,696		208,686
	Effect of dilutive securities	6,153		5,262		4,074
	Weighted average common shares and dilutive securities outstanding	219,380		215,958		212,760
	Earnings per share—basic	$	0.98	$	0.77	$	0.62
	Earnings per share—diluted	$	0.95	$	0.75	$	0.61

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2014
Share-based Compensation, Allocation and Classification in Financial Statements [Abstract]
Schedule of Share-based Payment Award, Valuation Assumptions	The fair value of each stock option granted is estimated on the date of grant using the Black-Scholes option-pricing model with the following weighted average assumptions:
		Year Ended December 31,
		2013
	Risk-free interest rate	1.2	%
	Average expected life in years	6.25
	Expected volatility	55.4	%
	Expected dividend yield	—	%
Summary Of Stock Options Activity	A summary of the Company’s stock options as of December 31, 2014, 2013 and 2012, and changes during the years then ended is presented below:
	(In thousands, except per share amounts)	Year Ended December 31,
		2014					2013						2012
		Number		Weighted			Number		Weighted				Number			Weighted
		of Stock		Average			of Stock		Average				of Stock			Average
		Options		Exercise			Options		Exercise				Options			Exercise
				Price					Price							Price
	Outstanding, beginning of year	4,272		$	8.11		6,298		$	7.66			9,616			$	7
	Granted, at fair market value	—		—			20		24.35				—			—
	Exercised	(1,454	)	7.74			(1,822	)	6.68				(2,436	)		5.09
	Expired	—		—			—		—				—			—
	Forfeited	(7	)	16.46			(224	)	8.41				(882	)		7.6
	Outstanding, end of year	2,811		$	8.28		4,272		$	8.11			6,298			$	7.66
	Options exercisable, end of year	2,707		$	7.87		2,346		$	7.8			1,936			$	6.55
Stock Options Outstanding And Exercisable	The following table summarizes information about stock options outstanding and exercisable as of December 31, 2014:
	(In thousands, except per share amounts)
	Options Outstanding								Options Exercisable
	Number of	Weighted			Weighted	Total			Number of		Weighted				Weighted		Total
	Underlying	Average			Average	Intrinsic			Underlying		Average				Average		Intrinsic
	Shares	Exercise			Remaining	Value			Shares		Exercise				Remaining		Value
		Price Per			Contractual						Price Per				Contractual
		Share			Life (Years)						Share				Life (Years)
	2,811	$	8.28		5.01	$	167,623		2,707		$	7.87			4.94		$	162,518
Summary Of Restricted Stock And Restricted Stock Units	A summary of the Company’s restricted stock and restricted stock units as of December 31, 2014, 2013 and 2012, and changes during the years then ended is presented below:
		Year Ended December 31,
	(In thousands, except per share amounts)	2014					2013						2012
		Number		Weighted			Number		Weighted				Number			Weighted
		of		Average			of		Average				of			Average
		Restricted		Fair Value			Restricted		Fair Value				Restricted			Fair Value
		Shares					Shares						Shares
	Outstanding, beginning of year	5,244		$	22.19		4,514		$	19.51			3,292			$	14.56
	Granted	1,061		54.17			1,682		26.35				2,658			22.92
	Forfeited	(958	)	20.98			(410	)	17.37				(758	)		16.73
	Vested	(837	)	19.49			(542	)	16.76				(678	)		11.66
	Outstanding, end of year	4,510		$	30.42		5,244		$	22.19			4,514			$	19.51

Risk_Management_and_Derivative1

Risk Management and Derivatives (Tables)	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
Changes in Foreign Currency Exchange Rates and Derivative Foreign Currency Forward Contracts	Included in other expense, net were the following amounts related to changes in foreign currency exchange rates and derivative foreign currency forward contracts:
	(In thousands)	Year Ended December 31,
		2014			2013			2012
	Unrealized foreign currency exchange rate gains (losses)	$	(11,739	)	$	(1,905	)	$	2,464
	Realized foreign currency exchange rate gains (losses)	2,247			477			(182		)
	Unrealized derivative gains (losses)	1			13			675
	Realized derivative gains (losses)	3,081			243			(3,030		)

Segment_Data_and_Related_Infor1

Segment Data and Related Information (Tables)	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
Reconciliation of Revenue from Segments to Consolidated
	(In thousands)	Year Ended December 31,
		2014			2013			2012
	Net revenues
	North America	$	2,796,390		$	2,193,739		$	1,726,733
	Other foreign countries and businesses	287,980			138,312			108,188
	Total net revenues	$	3,084,370		$	2,332,051		$	1,834,921
Reconciliation of Operating Profit (Loss) from Segments to Consolidated
	(In thousands)	Year Ended December 31,
		2014			2013			2012
	Operating income (loss)
	North America	$	372,347		$	271,338		$	200,084
	Other foreign countries and businesses	(18,392		)	(6,240		)	8,611
	Total operating income	353,955			265,098			208,695
	Interest expense, net	(5,335		)	(2,933		)	(5,183		)
	Other expense, net	(6,410		)	(1,172		)	(73		)
	Income before income taxes	$	342,210		$	260,993		$	203,439
Net Revenues by Product Category	Net revenues by product category are as follows:
	(In thousands)	Year Ended December 31,
		2014			2013			2012
	Apparel	$	2,291,520		$	1,762,150		$	1,385,350
	Footwear	430,987			298,825			238,955
	Accessories	275,425			216,098			165,835
	Total net sales	2,997,932			2,277,073			1,790,140
	Licensing and other revenues	86,438			54,978			44,781
	Total net revenues	$	3,084,370		$	2,332,051		$	1,834,921

Unaudited_Quarterly_Financial_1

Unaudited Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Data [Abstract]
Selected Quarterly Financial Data
	(In thousands)	Quarter Ended (unaudited)								Year Ended
		March 31,		June 30,		September 30,		December 31,		December 31,
	2014
	Net revenues	$	641,607	$	609,654	$	937,908	$	895,201	$	3,084,370
	Gross profit	300,690		299,952		465,300		446,264		1,512,206
	Income from operations	26,856		34,694		146,106		146,299		353,955
	Net income	13,538		17,690		89,105		87,709		208,042
	Earnings per share-basic	$	0.06	$	0.08	$	0.42	$	0.41	$	0.98
	Earnings per share-diluted	$	0.06	$	0.08	$	0.41	$	0.4	$	0.95
	2013
	Net revenues	$	471,608	$	454,541	$	723,146	$	682,756	$	2,332,051
	Gross profit	216,551		219,631		350,135		350,353		1,136,670
	Income from operations	13,492		32,310		120,829		98,467		265,098
	Net income	7,814		17,566		72,784		64,166		162,330
	Earnings per share-basic	$	0.04	$	0.08	$	0.34	$	0.3	$	0.77
	Earnings per share-diluted	$	0.04	$	0.08	$	0.34	$	0.3	$	0.75

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Narrative) (Detail)

0 Months Ended

12 Months Ended

12 Months Ended

Apr. 14, 2014

Jul. 09, 2012

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2014

Dec. 31, 2014

Dec. 31, 2014

Dec. 31, 2014

Dec. 31, 2014

Jan. 31, 2011

Jan. 31, 2011

Dec. 31, 2014

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2014

USD ($)

USD ($)

USD ($)

Dome Corporation

Furniture Office Equipment And Software

Furniture Office Equipment And Software

Site Improvement Buildings And Building Equipment

Site Improvement Buildings And Building Equipment

Fixtures And Displays

Japan, Yen

United States of America, Dollars

Customer A Concentration Risk [Member]

Customer A Concentration Risk [Member]

Customer A Concentration Risk [Member]

Customer A Concentration Risk [Member]

Customer B Concentration Risk [Member]

Minimum

Maximum

Minimum

Maximum

Dome Corporation

Dome Corporation

Accounts Receivable [Member]

Sales Revenue, Goods, Net [Member]

Sales Revenue, Goods, Net [Member]

Sales Revenue, Goods, Net [Member]

Accounts Receivable [Member]

JPY (¥)

USD ($)

Summary Of Significant Accounting Policies [Line Items]

Concentration Risk, Percentage

23.40%

14.40%

16.60%

16.60%

11.10%

Stock Issued During Period, Shares, Stock Splits

1

1

Interest and Dividend Income, Securities, Operating, Trading or Measured at Fair Value

$192,000

$23,700

$25,200

Allowance for doubtful accounts receivable

3,700,000

2,900,000

Property, Plant and Equipment, Useful Life

3 years

10 years

10 years

35 years

3 years

Interest Costs Capitalized

400,000

400,000

Accrued liabilities accrued compensation and benefits

61,400,000

56,700,000

Accrued Liabilities Accrued Marketing Expenses

14,000,000

11,900,000

Reserves For Customer Returns Allowances Markdowns And Discounts

68,900,000

43,800,000

Advertising Expense

333,000,000

246,500,000

205,400,000

Prepaid Advertising

31,100,000

22,000,000

Shipping and handling costs

55,300,000

46,100,000

34,800,000

Cost Method Investments

$13,400,000

$15,200,000

¥ 1,140,000,000

$15,500,000

Ownership Percentage Cost Method Investment

19.50%

Acquisitions_Narrative_Details

Acquisitions Narrative (Details) (USD $)	3 Months Ended	12 Months Ended			0 Months Ended
	Jun. 30, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 06, 2013
Business Acquisition [Line Items]
Proceeds from revolving credit facility	$100,000,000	$0	$100,000,000	$0
Goodwill, Acquired During Period		1,012,000
Finite-Lived Intangible Assets, Gross		35,019,000	25,762,000
Technology-Based Intangible Assets [Member]
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross		12,000,000	12,000,000
Trade Names [Member]
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross		5,000,000	5,000,000
Customer Relationships [Member]
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross		11,927,000	3,600,000
Minimum
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life		55 months
Maximum
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life		120 months
MapMyFitness
Business Acquisition [Line Items]
Equity Interest in Acquiree, Percentage					100.00%
Payments to Acquire Businesses, Gross					150,000,000
Proceeds from revolving credit facility					100,000,000
Finite-Lived Intangibles Acquired					20,600,000
Goodwill, Acquired During Period					122,200,000
Other Assets, Net Acquired					6,600,000
Deferred Tax Assets, Net Acquired					4,700,000
Acquisitions Related Costs					2,500,000
MapMyFitness | Technology-Based Intangible Assets [Member]
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life		84 months
MapMyFitness | Trade Names [Member]
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life		48 months
MapMyFitness | Customer Relationships [Member]
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross		$3,600,000
Finite-Lived Intangible Asset, Useful Life		24 months
MapMyFitness | Minimum
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life		2 years
MapMyFitness | Maximum
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life		7 years

Property_And_Equipment_Net_Com

Property And Equipment, Net (Components Of Property And Equipment) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Property, Plant and Equipment [Line Items]
Property and equipment	$522,376	$396,086
Accumulated depreciation	-216,812	-172,134
Property and equipment, net	305,564	223,952
Leasehold and tenant improvements
Property, Plant and Equipment [Line Items]
Property and equipment	128,088	97,776
Furniture, fixtures and displays
Property, Plant and Equipment [Line Items]
Property and equipment	80,035	68,045
Buildings
Property, Plant and Equipment [Line Items]
Property and equipment	46,419	45,903
Software
Property, Plant and Equipment [Line Items]
Property and equipment	67,506	51,984
Office equipment
Property, Plant and Equipment [Line Items]
Property and equipment	51,531	39,551
Plant equipment
Property, Plant and Equipment [Line Items]
Property and equipment	70,317	45,509
Land
Property, Plant and Equipment [Line Items]
Property and equipment	17,628	17,628
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment	57,677	28,471
Other
Property, Plant and Equipment [Line Items]
Property and equipment	$3,175	$1,219

Property_And_Equipment_Net_Nar

Property And Equipment, Net (Narrative) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Depreciation expense	$72,093	$50,549	$43,082
Property And Equipment [Member]
Property, Plant and Equipment [Line Items]
Depreciation expense	$63,600	$48,300	$39,800

Goodwill_and_Intangible_Assets2

Goodwill and Intangible Assets, Net - Schedule of Goodwill (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014
Goodwill [Roll Forward]
Goodwill	$122,244
Goodwill, Acquired During Period	1,012
Goodwill	123,256
North America [Member]
Goodwill [Roll Forward]
Goodwill	119,799
Goodwill, Acquired During Period	0
Goodwill	119,799
Other Foreign Countries [Member]
Goodwill [Roll Forward]
Goodwill	2,445
Goodwill, Acquired During Period	1,012
Goodwill	$3,457

Goodwill_and_Intangible_Assets3

Goodwill and Intangible Assets, Net - Summary Of Intangible Assets (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Carrying Amount	$35,019	$25,762
Intangible assets, Accumulated Amortization	-11,607	-3,354
Intangible assets, Net Carrying Amount	23,412	22,408
Indefinite-lived intangible assets	2,818	1,689
Intangible assets, net	26,230	24,097
Technology-Based Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Carrying Amount	12,000	12,000
Intangible assets, Accumulated Amortization	-1,907	-126
Intangible assets, Net Carrying Amount	10,093	11,874
Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Carrying Amount	5,000	5,000
Intangible assets, Accumulated Amortization	-1,353	-53
Intangible assets, Net Carrying Amount	3,647	4,947
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Carrying Amount	11,927	3,600
Intangible assets, Accumulated Amortization	-4,692	-38
Intangible assets, Net Carrying Amount	7,235	3,562
Lease-related intangible assets
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Carrying Amount	3,896	3,896
Intangible assets, Accumulated Amortization	-2,762	-2,605
Intangible assets, Net Carrying Amount	1,134	1,291
Other
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross Carrying Amount	2,196	1,266
Intangible assets, Accumulated Amortization	-893	-532
Intangible assets, Net Carrying Amount	$1,303	$734

Goodwill_and_Intangible_Assets4

Goodwill and Intangible Assets, Net - Narrative (Details) (USD $)	12 Months Ended			0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 06, 2013
Finite-Lived Intangible Assets [Line Items]
Goodwill, Acquired During Period	$1,012,000
Amortization expense	8,500,000	1,600,000	2,200,000
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	7,862,000
Estimated Amortization of Intangible Assets, 2015	6,118,000
Estimated Amortization of Intangible Assets, 2016	3,236,000
Estimated Amortization of Intangible Assets, 2017	2,074,000
Estimated Amortization of Intangible Assets, 2018	1,966,000
Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated useful life of intangible assets	55 months
Minimum | Lease-related intangible assets
Finite-Lived Intangible Assets [Line Items]
Estimated useful life of intangible assets	9 months
Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated useful life of intangible assets	120 months
Maximum | Lease-related intangible assets
Finite-Lived Intangible Assets [Line Items]
Estimated useful life of intangible assets	15 years
MapMyFitness
Finite-Lived Intangible Assets [Line Items]
Goodwill, Acquired During Period				122,200,000
MapMyFitness | Technology-Based Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life of intangible assets	84 months
MapMyFitness | Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life of intangible assets	48 months
MapMyFitness | Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life of intangible assets	24 months
MapMyFitness | Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated useful life of intangible assets	2 years
MapMyFitness | Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated useful life of intangible assets	7 years
Mexican Distributor [Member]
Finite-Lived Intangible Assets [Line Items]
Goodwill, Acquired During Period	$1,000,000
Mexican Distributor [Member] | Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life of intangible assets	36 months

Goodwill_and_Intangible_Assets5

Goodwill and Intangible Assets, Net Finite-Lived Intangible Assets, Estimated Future Amortization Expense (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Finite-Lived Intangibles Assets, Estimated Future Amortization Expense [Line Items]
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	$7,862
Finite-Lived Intangible Assets, Amortization Expense, Year Two	6,118
Finite-Lived Intangible Assets, Amortization Expense, Year Three	3,236
Finite-Lived Intangible Assets, Amortization Expense, Year Four	2,074
Finite-Lived Intangible Assets, Amortization Expense, Year Five	1,966
Finite-Lived Intangible Assets, Amortization Expense, after Year Five	2,156
Finite-Lived Intangible Assets, Net	$23,412	$22,408

Credit_Facility_and_Long_Term_2

Credit Facility and Long Term Debt - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended			1 Months Ended
	Jun. 30, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2012	31-May-14	29-May-14
Debt Disclosure [Line Items]
Credit facility maximum borrowing capacity	$650,000,000
Commitment fee as percentage of the committed line amount less outstanding borrowings and letters of credit		1250.00%
Long term debt agreements principal outstanding		2,000,000	4,900,000	11,900,000	11,900,000
Weighted average interest rate on outstanding borrowings		3.10%	3.30%	3.70%
Repayments of Long-term Debt		4,972,000	5,471,000	44,330,000
Interest expense		5,300,000	2,900,000	5,200,000
Proceeds from revolving credit facility	100,000,000	0	100,000,000	0
Payments on revolving credit facility	-100,000,000	100,000,000	0	0
Deferred Finance Costs, Net							1,700,000
LIBOR Rate [Member]
Debt Disclosure [Line Items]
Interest rate margin, minimum		1.00%
Interest rate margin, maximum		1.25%
Prime Rate [Member]
Debt Disclosure [Line Items]
Interest rate margin, minimum		0.00%
Interest rate margin, maximum		0.25%
Term Loan Facility [Member]
Debt Disclosure [Line Items]
Weighted average interest rate on outstanding borrowings		1.20%
Swingline Loan [Member]
Debt Disclosure [Line Items]
Credit facility maximum borrowing capacity		50,000,000
Prior Revolving Credit Facility [Member]
Debt Disclosure [Line Items]
Credit facility maximum borrowing capacity	325,000,000
Letter of Credit [Member]
Debt Disclosure [Line Items]
Credit facility maximum borrowing capacity		50,000,000
Revolving Credit Facility [Member]
Debt Disclosure [Line Items]
Credit facility maximum borrowing capacity		400,000,000
Additional increase under credit facility		150,000,000
Term Loan Facility [Member]
Debt Disclosure [Line Items]
Credit facility maximum borrowing capacity		250,000,000
Initial Term Loan [Member]
Debt Disclosure [Line Items]
Credit facility maximum borrowing capacity		150,000,000
Delayed Draw Term Loan [Member]
Debt Disclosure [Line Items]
Credit facility maximum borrowing capacity		100,000,000
Secured Debt [Member]
Debt Disclosure [Line Items]
Debt Facility Term Period					7 years
Weighted average interest rate on outstanding borrowings		1.70%	1.70%	1.70%
Debt Instrument, Maturity Date					1-Dec-19
Secured Debt		46,000,000	48,000,000	50,000,000	50,000,000
Secured Debt [Member] | LIBOR Rate [Member]
Debt Disclosure [Line Items]
Debt Instrument, Basis Spread on Variable Rate				1.50%
Line of Credit [Member]
Debt Disclosure [Line Items]
Debt Facility Term Period						5 years
Debt Instrument, Maturity Date						1-May-19
Interest Expense [Member]
Debt Disclosure [Line Items]
Line of Credit Facility, Covenant Terms		1
EBITDA [Member]
Debt Disclosure [Line Items]
Line of Credit Facility, Covenant Terms		3.5
Debt [Member]
Debt Disclosure [Line Items]
Line of Credit Facility, Covenant Terms		3.25
EBITDA [Member]
Debt Disclosure [Line Items]
Line of Credit Facility, Covenant Terms		1
Interest Rate Swap [Member]
Debt Disclosure [Line Items]
Derivative, Gain (Loss) on Derivative, Net		$1,700,000	$300,000

Credit_Facility_and_Long_Term_3

Credit Facility and Long Term Debt - Scheduled Maturities Of Long Term Debt (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Debt Disclosure [Abstract]
2014	$28,951
2015	27,000
2016	27,000
2017	27,000
2018	138,250
2020 and thereafter	36,000
Total scheduled maturities of long term debt	284,201
Less current maturities of long term debt	-28,951	-4,972
Long term debt obligations	$255,250	$47,951

Commitments_And_Contingencies_1

Commitments And Contingencies (Narrative) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Commitments and Contingencies Disclosure [Abstract]
Lease Expiration Date	2028
Rent expense included in selling, general and administrative expense	$59	$41.80	$31.10
Contingent rent expense	$11	$7.80	$6.20

Commitments_And_Contingencies_2

Commitments And Contingencies (Future Minimum Lease Payments For Non-Cancelable Real Property Operating Leases) (Details) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Operating Leased Assets
2014	$56,452
2015	57,079
2016	52,172
2017	48,345
2018	44,313
2020 and thereafter	214,214
Total future minimum lease payments	$472,575

Commitments_And_Contingencies_3

Commitments And Contingencies (Future Minimum Payments Under Sponsorship And Other Marketing Agreements) (Details) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Schedule of Future Minimum Payments on Sponsorship and Other Marketing Agreements [Line Items]
Future Minimum Payments Under Sponsorship And Other Marketing Agreements Due 2014	$90,056
Future Minimum Payments Under Sponsorship And Other Marketing Agreements Due 2015	71,654
Future Minimum Payments Under Sponsorship And Other Marketing Agreements Due 2016	56,734
Future Minimum Payments Under Sponsorship And Other Marketing Agreements Due 2017	44,982
Future Minimum Payments Under Sponsorship And Other Marketing Agreements Due 2018	33,155
Future Minimum Payments Under Sponsorship And Other Marketing Agreements Due 2019 and Thereafter	96,345
Total future minimum sponsorship and other marketing payments	$392,926

Stockholders_Equity_Details

Stockholders' Equity (Details) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
	vote
Class A Common Stock
Class of Stock [Line Items]
Shares authorized	400,000,000	400,000,000
Common Stock, Value, Issued	$59	$57
Par value per share	$0.00	$0.00
Number of votes per share	1
Number of shares of Class A Common Shares issued per share upon conversion	3,400,000	2,600,000	2,400,000
Class B Convertible Common Stock
Class of Stock [Line Items]
Shares authorized	36,600,000	40,000,000
Common Stock, Value, Issued	$12	$13
Par value per share	$0.00	$0.00
Number of votes per share	10
Number of shares of Class A Common Shares issued per share upon conversion	-3,400,000	-2,600,000	-2,400,000
Class A Common Stock And Class B Convertible Common Stock
Class of Stock [Line Items]
Class B Convertible Common Stock converted to Class A Common Stock, ratio	one-for-one
Minimum | Class A Common Stock And Class B Convertible Common Stock
Class of Stock [Line Items]
Beneficial ownership percentage of CEO	15.00%

Fair_Value_Measurements_Financ

Fair Value Measurements (Financial Assets And (Liabilities) Measured At Fair Value) (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
TOLI policies held by the Rabbi Trust	$0	$0
Deferred Compensation Plan obligations	0	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
TOLI policies held by the Rabbi Trust	4,734,000	4,625,000
Deferred Compensation Plan obligations	-4,525,000	-3,338,000
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
TOLI policies held by the Rabbi Trust	0	0
Deferred Compensation Plan obligations	0	0
Foreign Exchange Forward [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contract, Asset, Fair Value Disclosure	806,000	12,100
Foreign Exchange Forward [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contract, Asset, Fair Value Disclosure	0	0
Foreign Exchange Forward [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contract, Asset, Fair Value Disclosure	806,000	12,000
Foreign Exchange Forward [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contract, Asset, Fair Value Disclosure	0	0
Interest Rate Swap [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest Rate Derivatives, at Fair Value, Net	0	0
Interest Rate Swap [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest Rate Derivatives, at Fair Value, Net	-607,000	1,087,000
Interest Rate Swap [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest Rate Derivatives, at Fair Value, Net	$0	$0

Provision_For_Income_Taxes_Inc

Provision For Income Taxes - Income (Loss) Before Income Taxes (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Taxes Payable [Abstract]
United States	$269,503	$196,558	$155,514
Foreign	72,707	64,435	47,925
Income before income taxes	$342,210	$260,993	$203,439

Provision_For_Income_Taxes_Com

Provision For Income Taxes - Components Of The Provision For Income Taxes (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Taxes Payable [Abstract]
Federal, Current	$110,439	$85,542	$66,533
State, Current	24,419	19,130	12,962
Other foreign countries, Current	16,489	13,295	8,139
Provision for income taxes, Current	151,347	117,967	87,634
Federal, Deferred	-15,368	-14,722	-9,606
State, Deferred	-4,073	-5,541	-3,563
Other foreign countries, Deferred	2,262	959	196
Provision for income taxes, Deferred	-17,179	-19,304	-12,973
Provision for income taxes	$134,168	$98,663	$74,661

Provision_For_Income_Taxes_Rec

Provision For Income Taxes - Reconciliation From The U.S. Statutory Federal Income Tax Rate To Effective Income Tax Rate (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Taxes Payable [Abstract]
U.S. federal statutory income tax rate	35.00%	35.00%	35.00%
State taxes, net of federal tax impact	3.80%	2.40%	2.10%
Unrecognized tax benefits	1.90%	2.50%	2.70%
Nondeductible expenses	1.00%	1.10%	0.60%
Foreign rate differential	-4.50%	-4.80%	-4.90%
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Percent	2.50%	1.50%	0.80%
Other	-0.50%	0.10%	0.40%
Effective income tax rate	39.20%	37.80%	36.70%

Provision_For_Income_Taxes_Def

Provision For Income Taxes - Deferred Tax Assets And Liabilities (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Deferred tax asset
Stock-based compensation	$35,161	$25,472
Allowance for doubtful accounts and other reserves	24,774	16,262
Foreign net operating loss carryforward	16,302	13,829
U. S. net operating loss carryforward	4,733	10,119
Deferred rent	11,005	8,980
Inventory obsolescence reserves	8,198	6,269
Tax basis inventory adjustment	5,845	5,633
State tax credits, net of federal tax impact	4,245	5,342
Foreign tax credits	5,131	3,807
Accrued expenses	11,398	3,403
Deferred compensation	1,858	1,372
Other	4,592	5,889
Total deferred tax assets	133,242	106,377
Less: valuation allowance	-15,550	-8,091
Total net deferred tax assets	117,692	98,286
Deferred tax liability
Property, plant and equipment	-17,638	-13,375
Intangible assets	-7,010	-8,627
Prepaid expenses	-6,424	-6,380
Other	-612	-447
Total deferred tax liabilities	-31,684	-28,829
Total deferred tax assets, net	$86,008	$69,457

Provision_For_Income_Taxes_Unr

Provision For Income Taxes - Unrecognized Tax Benefits Balances (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning of year	$21,712	$15,297	$9,783
Increases as a result of tax positions taken in a prior period	250	0	0
Decreases as a result of tax positions taken in a prior period	0	0	0
Increases as a result of tax positions taken during the current period	8,947	7,526	5,702
Decreases as a result of tax positions taken during the current period	0	0	0
Decreases as a result of settlements during the current period	0	0	0
Reductions as a result of a lapse of statute of limitations during the current period	-2,556	-1,111	-188
End of year	$28,353	$21,712	$15,297

Provision_For_Income_Taxes_Nar

Provision For Income Taxes - Narrative (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Contingency [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards, Domestic	$4,733,000	$10,119,000
Foreign net operating loss carryforward	16,302,000	13,829,000
Valuation allowance recorded during period	6,100,000
Deferred tax assets associated with foreign tax credits	5,131,000	3,807,000
Valuation Allowance, Deferred Tax Asset, Tax Credit Carryforwards, Foreign, Change in Amount	1,300,000
Cash and Cash Equivalents Held by Foreign Subsidiaries	129,200,000
Undistributed Earnings, Basic	176,800,000
Unrecognized Tax Benefits Including Interest And Penalties	31,300,000	24,100,000
Unrecognized tax benefits excluding interest and penalties that would impact the effective tax rate if recognized	26,300,000
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	3,000,000	2,400,000	1,800,000
Accrual of interest and penalties	1,200,000	1,000,000	700,000
Minimum
Income Tax Contingency [Line Items]
Deferred Tax Assets, Net Operating Loss Carryforwards, Domestic Expiration	2029
Deferred Tax Assets, Net Operating Loss Carryforwards, Foreign Expiration	2016
Maximum
Income Tax Contingency [Line Items]
Deferred Tax Assets, Net Operating Loss Carryforwards, Domestic Expiration	2033
Deferred Tax Assets, Net Operating Loss Carryforwards, Foreign Expiration	2020
Net [Member]
Income Tax Contingency [Line Items]
Foreign net operating loss carryforward	0
Net [Member] | MapMyFitness
Income Tax Contingency [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards, Domestic	0	10,500,000
Gross [Member]
Income Tax Contingency [Line Items]
Foreign net operating loss carryforward	62,000,000
Gross [Member] | MapMyFitness
Income Tax Contingency [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards, Domestic	$0	$42,500,000

Earnings_Per_Share_Narrative_D

Earnings Per Share (Narrative) (Detail)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares excluded from the computation of diluted earnings per share	0	116,900	208,900

Earnings_Per_Share_Schedule_Of

Earnings Per Share (Schedule Of Reconciliation Of Basic Earnings Per Share To Diluted Earnings Per Share) (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Disclosure Earnings Per Share Schedule Of Reconciliation Of Basic Earnings Per Share To Diluted Earnings Per Share [Abstract]
Net income	$87,709	$89,105	$17,690	$13,538	$64,166	$72,784	$17,566	$7,814	$208,042	$162,330	$128,778
Effect of dilutive securities									6,153	5,262	4,074
Weighted average common shares and dilutive securities outstanding									219,380	215,958	212,760
Earnings per share - basic	$0.41	$0.42	$0.08	$0.06	$0.30	$0.34	$0.08	$0.04	$0.98	$0.77	$0.62
Earnings per share - diluted	$0.40	$0.41	$0.08	$0.06	$0.30	$0.34	$0.08	$0.04	$0.95	$0.75	$0.61
Weighted Average Number of Shares Outstanding, Basic									213,227	210,696	208,686

StockBased_Compensation_Schedu

Stock-Based Compensation - Schedule of Share-based Payment Award, Valuation Assumptions (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation, Allocation and Classification in Financial Statements [Abstract]
Risk-free interest rate, minimum	0.00%	1.24%	0.00%
Risk-free interest rate, maximum	0.00%	1.24%	0.00%
Average expected life in years	0 years	6 years 3 months	0 years
Expected volatility, minimum	0.00%	55.38%	0.00%
Expected volatility, maximum	0.00%	55.38%	0.00%
Expected dividend yield	0.00%	0.00%	0.00%

StockBased_Compensation_Summar

Stock-Based Compensation - Summary Of Stock Options Activity (Details) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, beginning of year, Number of Stock Options	4,272	6,298	9,616
Granted, at fair market value, Number of Stock Options	0	20	0
Exercised, Number of Stock Options	-1,454	-1,822	-2,436
Expired, Number of Stock Options	0	0	0
Forfeited, Number of Stock Options	-7	-224	-882
Outstanding, end of year, Number of Stock Options	2,811	4,272	6,298
Options exercisable, end of year, Number of Stock Options	2,707	2,346	1,936
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding, beginning of year, Weighted Average Exercise Price	$8.11	$7.66	$7
Granted, at fair market value, Weighted Average Exercise Price	$0	$24.35	$0
Exercised, Weighted Average Exercise Price	$7.74	$6.68	$5.09
Expired, Weighted Average Exercise Price	$0	$0	$0
Forfeited, Weighted Average Exercise Price	$16.46	$8.41	$7.60
Outstanding, end of year, Weighted Average Exercise Price	$8.28	$8.11	$7.66
Options exercisable, end of year, Weighted Average Exercise Price	$7.87	$7.80	$6.55

StockBased_Compensation_Stock_

Stock-Based Compensation - Stock Options Outstanding And Exercisable (Details) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation, Allocation and Classification in Financial Statements [Abstract]
Options Outstanding, Number of Underlying Shares	2,811	4,272	6,298	9,616
Options Outstanding, Weighted Average Exercise Price Per Share	$8.28	$8.11	$7.66	$7
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	5 years 0 months 4 days
Options Outstanding, Total Intrinsic Value	$167,623
Options Exercisable, Number of Underlying Shares	2,707	2,346	1,936
Options Exercisable, Weighted Average Exercise Price Per Share	$7.87	$7.80	$6.55
Options Exercisable, Weighted Average Remaining Contractual Life (Years)	4 years 11 months 9 days
Options Exercisable, Total Intrinsic Value	$162,518

StockBased_Compensation_Summar1

Stock-Based Compensation - Summary Of Restricted Stock And Restricted Stock Units (Details) (Restricted Stock And Restricted Stock Units [Member], USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Restricted Stock And Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding, beginning of year, Number of Restricted Shares	5,244	4,514	3,292
Performance-based restricted stock units awarded	1,061	1,682	2,658
Forfeited, Number of Restricted Shares	-958	-410	-758
Vested, Number of Restricted Shares	-837	-542	-678
Outstanding, end of year, Number of Restricted Shares	4,510	5,244	4,514
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Outstanding, beginning of year, Weighted Average Value	$22.19	$19.51	$14.56
Granted, Weighted Average Fair Value (per share)	$54.17	$26.35	$22.92
Forfeited, Weighted Average Value	$20.98	$17.37	$16.73
Vested, Weighted Average Value	$19.49	$16.76	$11.66
Outstanding, end of year, Weighted Average Value	$30.42	$22.19	$19.51

StockBased_Compensation_Narrat

Stock-Based Compensation - Narrative (Details) (USD $)	12 Months Ended					3 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2015	Dec. 31, 2006	Sep. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation	$50,812,000	$43,184,000	$19,845,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	28,600,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	1 year
Granted, at fair market value, Number of Stock Options	0	20,000	0
Options Outstanding, Weighted Average Exercise Price Per Share	$8.28	$8.11	$7.66					$8.11			$7
Two Thousand Five Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	19,300,000
Non Employee Directors Fair Value Of Stock Awards	75,000			125,000
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	2,800,000
Employee Stock Purchase Program Discount Rate From Fair Market Value	15.00%
Stock Issued During Period, Shares, Employee Stock Purchase Plans	87,600	108,400	113,800
Director Compensation Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non Employee Directors Fair Value Of Stock Awards	100,000
Non Employee Directors Stock Awards Percentage Of Each Award Vested Following Grant Date	100.00%
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value		$12.91
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value	73,000,000	44,100,000	44,500,000
Warrant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights					1,900,000
fair Value Of Warrants Issued					8,500,000
Term Of Warrants Issued					12 years
Class of Warrant or Right, Exercise Price of Warrants or Rights					9.25
Certain Executives and Key Employees [Member] | Performance Based Restricted Stock Units [Member] | Two Thousand Five Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	38,400,000	30,800,000	4,100,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	1,000,000	1,400,000	2,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$30.30
Allocated Share-based Compensation Expense, Cumulative Adjustment						3,800,000	6,600,000	11,300,000	9,000,000	2,400,000
Additional Stock Based Compensation That Would Have Been Recorded If Operating Income Targets Had Been Deemed Probable	$2,700,000

Other_Employee_Benefits_Detail

Other Employee Benefits (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Compensation Related Costs [Abstract]
401(k) contribution matching expense	$4.90	$2.70	$2.30
Deferred compensation plan obligations included in other long term liabilities	4.5	3.3
Cash-surrender value of trust owned life insurance policies	$4.70	$4.60

Recovered_Sheet1

Risk Management And Derivatives (Narrative) (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Derivative [Line Items]
Maturity of foreign currency forward contract	11 months
Foreign Currency Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net	$400,000
Minimum Remaining Maturity of Foreign Currency Derivatives	1 month
Secured Debt [Member]
Derivative [Line Items]
Secured Debt	46,000,000	48,000,000	50,000,000
Foreign Exchange Forward [Member]
Derivative [Line Items]
Foreign Currency Contract, Asset, Fair Value Disclosure	806,000	12,100
Interest Rate Swap [Member]
Derivative [Line Items]
Notional Amount of Interest Rate Derivatives	188,100,000
Derivative, Gain (Loss) on Derivative, Net	1,700,000	300,000
Interest Rate Derivative Liabilities, at Fair Value	600,000
Interest Rate Derivative Assets, at Fair Value	1,100,000
Foreign Currency Forward Contracts [Member]
Derivative [Line Items]
Notional Amount of Interest Rate Derivatives	$123,300,000

Recovered_Sheet2

Risk Management And Derivatives (Changes In Foreign Currency Exchange Rates And Derivative Foreign Currency Forward Contracts) (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Foreign Currency Exchange Gain Loss [Line Items]
Unrealized foreign currency exchange rate gains (losses)	($11,739)	($1,905)	$2,464
Foreign Currency Exchange Rates [Member]
Foreign Currency Exchange Gain Loss [Line Items]
Unrealized foreign currency exchange rate gains (losses)	-11,739	-1,905	2,464
Realized foreign currency exchange rate gains (losses)	2,247	477	-182
Foreign Currency Forward Contracts [Member]
Foreign Currency Exchange Gain Loss [Line Items]
Unrealized derivative gains (losses)	1	13	675
Realized derivative gains (losses)	($3,081)	($243)	$3,030

Related_Party_Transactions_Det

Related Party Transactions (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2016
Related Party - Software License Agreement [Member]
Related Party Transaction [Line Items]
Fees paid	$5,200,000	$3,700,000	$1,900,000
Amount payable to related party	0	0
Related Party - Operating Lease Agreement [Member]
Related Party Transaction [Line Items]
Fees paid	1,800,000	1,000,000	800,000
Amount payable to related party	0	0
Related Party Operating Lease Agreement, Office Space [Member]
Related Party Transaction [Line Items]
Fees paid				$1,100,000
Lease Term Remaining				10 years
Annual Rent Escalation, Percent				2.00%

Recovered_Sheet3

Segment Data And Related Information (Narrative) (Details) (UNITED STATES, USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
UNITED STATES
Segment Reporting, Revenue Reconciling Item [Line Items]
Total net revenues in the United States	$2,670.40	$2,082.50	$1,650.40

Recovered_Sheet4

Segment Data And Related Information (Geographic Distribution Of The Company's Net Revenues And Operating Income) (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Total net revenues	$895,201	$937,908	$609,654	$641,607	$682,756	$723,146	$454,541	$471,608	$3,084,370	$2,332,051	$1,834,921
Total operating income	146,299	146,106	34,694	26,856	98,467	120,829	32,310	13,492	353,955	265,098	208,695
Interest expense, net									-5,335	-2,933	-5,183
Other expense, net									-6,410	-1,172	-73
Income before income taxes									342,210	260,993	203,439
North America [Member]
Segment Reporting Information [Line Items]
Total net revenues									2,796,390	2,193,739	1,726,733
Total operating income									372,347	271,338	200,084
Other Foreign Countries & Businesses [Member]
Segment Reporting Information [Line Items]
Total net revenues									287,980	138,312	108,188
Total operating income									($18,392)	($6,240)	$8,611

Segment_Data_And_Related_Infor2

Segment Data And Related Information (Net Revenues By Product Category) (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Total net sales									$2,997,932	$2,277,073	$1,790,140
License revenues									86,438	54,978	44,781
Total net revenues	895,201	937,908	609,654	641,607	682,756	723,146	454,541	471,608	3,084,370	2,332,051	1,834,921
Apparel [Member]
Segment Reporting Information [Line Items]
Total net sales									2,291,520	1,762,150	1,385,350
Footwear [Member]
Segment Reporting Information [Line Items]
Total net sales									430,987	298,825	238,955
Accessories [Member]
Segment Reporting Information [Line Items]
Total net sales									$275,425	$216,098	$165,835

Unaudited_Quarterly_Financial_2

Unaudited Quarterly Financial Data (Selected Quarterly Financial Data) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Data [Abstract]
Net revenues	$895,201	$937,908	$609,654	$641,607	$682,756	$723,146	$454,541	$471,608	$3,084,370	$2,332,051	$1,834,921
Gross profit	446,264	465,300	299,952	300,690	350,353	350,135	219,631	216,551	1,512,206	1,136,670	879,297
Income from operations	146,299	146,106	34,694	26,856	98,467	120,829	32,310	13,492	353,955	265,098	208,695
Net income	$87,709	$89,105	$17,690	$13,538	$64,166	$72,784	$17,566	$7,814	$208,042	$162,330	$128,778
Earnings per share - basic	$0.41	$0.42	$0.08	$0.06	$0.30	$0.34	$0.08	$0.04	$0.98	$0.77	$0.62
Earnings per share - diluted	$0.40	$0.41	$0.08	$0.06	$0.30	$0.34	$0.08	$0.04	$0.95	$0.75	$0.61

Subsequent_Events_Details

Subsequent Events (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Jan. 05, 2015	Feb. 03, 2015
Class A Common Stock And Class B Convertible Common Stock
Subsequent Event [Line Items]
Class B Convertible Common Stock converted to Class A Common Stock, ratio	one-for-one
Endomondo [Member]
Subsequent Event [Line Items]
Equity Interest in Acquiree, Percentage		100.00%
Payments to Acquire Businesses		$85
Acquisitions Related Costs	0.8
MyFitnessPal [Member]
Subsequent Event [Line Items]
Payments to Acquire Businesses			$475

Valuation_And_Qualifying_Accou1

Valuation And Qualifying Accounts (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Allowance For Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	$2,938	$3,286	$4,070
Charged to Costs and Expenses	1,028	210	-108
Write-Offs Net of Recoveries	-273	-558	-676
Balance at End of Year	3,693	2,938	3,286
Sales Returns And Allowances [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	34,102	32,919	20,600
Charged to Costs and Expenses	156,791	135,739	107,536
Write-Offs Net of Recoveries	-137,920	-134,556	-95,217
Balance at End of Year	52,973	34,102	32,919
Deferred Tax Asset Valuation Allowance [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	8,091	3,996	1,784
Charged to Costs and Expenses	7,581	4,095	2,855
Write-Offs Net of Recoveries	-122	0	-643
Balance at End of Year	$15,550	$8,091	$3,996