Groupon (GRPN) 10-K 13 Feb 15 2014 FY Annual report Financial data

Cover_Document

Cover Document (USD $)	12 Months Ended
	Dec. 31, 2014	Jun. 30, 2014	Feb. 09, 2015
Entity Registrant Name	Groupon, Inc.
Entity Central Index Key	1490281
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Amendment Flag	FALSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float		$3,340,614,720
Common Class A [Member]
Common Stock, Shares, Outstanding			672,963,103
Common Class B [Member]
Common Stock, Shares, Outstanding			2,399,976

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$1,071,913	$1,240,472
Accounts receivable, net	105,154	83,673
Deferred income taxes	16,271	27,938
Prepaid expense and other current assets	207,991	210,415
Total current assets	1,401,329	1,562,498
Property, equipment and software, net	182,475	134,423
Goodwill	447,810	220,827
Intangible assets, net	110,557	28,443
Investments	24,298	20,652
Deferred income taxes, non-current	41,835	35,941
Other non-current assets	19,293	39,226
Total Assets	2,227,597	2,042,010
Current liabilities:
Accounts payable	21,855	27,573
Accrued merchant and supplier payables	910,567	752,943
Accrued expenses	230,352	226,986
Deferred income taxes	32,510	47,558
Other current liabilities	130,312	132,718
Total current liabilities	1,325,596	1,187,778
Deferred income taxes, non-current	773	10,853
Other non-current liabilities	136,284	131,697
Total Liabilities	1,462,653	1,330,328
Commitments and contingencies
Stockholders' Equity
Additional paid-in capital	1,847,420	1,584,211
Treasury stock, at cost	-198,467	-46,587
Accumulated deficit	-921,960	-848,870
Accumulated other comprehensive income	35,763	24,830
Total Groupon, Inc. Stockholders' Equity	762,826	713,651
Noncontrolling interests	2,118	-1,969
Total Equity	764,944	711,682
Total Liabilities and Equity	2,227,597	2,042,010
Common Class A [Member]
Stockholders' Equity
Common Stock, Value, Issued	70	67
Common Class B [Member]
Stockholders' Equity
Common Stock, Value, Issued	0	0
Common Stock [Member]
Stockholders' Equity
Common Stock, Value, Issued	$0	$0

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets Parenthetical (USD $)	Dec. 31, 2014	Dec. 31, 2013
Common Stock [Member]
Condensed Consolidated Balance Sheet Parenthetical [Line Items]
Common Stock, Par Value	0.0001	0.0001
Common Stock, Shares Authorized	2,010,000,000	2,010,000,000
Common Stock, Shares, Issued	0	0
Common Stock, Shares, Outstanding	0	0
Common Class A [Member]
Condensed Consolidated Balance Sheet Parenthetical [Line Items]
Common Stock, Par Value	0.0001	0.0001
Common Stock, Shares Authorized	2,000,000,000	2,000,000,000
Common Stock, Shares, Issued	699,008,084	670,149,976
Common Stock, Shares, Outstanding	671,768,980	665,717,176
Common Class B [Member]
Condensed Consolidated Balance Sheet Parenthetical [Line Items]
Common Stock, Par Value	0.0001	0.0001
Common Stock, Shares Authorized	10,000,000	10,000,000
Common Stock, Shares, Issued	2,399,976	2,399,976
Common Stock, Shares, Outstanding	2,399,976	2,399,976
Treasury Stock [Member]
Condensed Consolidated Balance Sheet Parenthetical [Line Items]
Treasury Stock, Shares	27,239,104	4,432,800

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenue:
Third party and other	$1,627,539	$1,654,654	$1,879,729
Direct	1,564,149	919,001	454,743
Total revenue	3,191,688	2,573,655	2,334,472
Cost of revenue:
Third party and other	241,885	232,062	297,739
Direct	1,400,617	840,060	421,201
Total cost of revenue	1,642,502	1,072,122	718,940
Gross profit	1,549,186	1,501,533	1,615,532
Operating expenses:
Marketing	269,043	214,824	336,854
Selling, general and administrative	1,293,716	1,210,966	1,179,080
Acquisition-related expense (benefit), net	1,269	-11	897
Total operating expenses	1,564,028	1,425,779	1,516,831
(Loss) income from operations	-14,842	75,754	98,701
Other expense, net	-33,353	-94,663	-3,759
(Loss) income before provision for income taxes	-48,195	-18,909	94,942
Provision for income taxes	15,724	70,037	145,973
Net loss	-63,919	-88,946	-51,031
Net income attributable to noncontrolling interests	-9,171	-6,447	-3,742
Net loss attributable to Groupon, Inc.	-73,090	-95,393	-54,773
Adjustment of redeemable noncontrolling interests to redemption value	0	0	-12,604
Net loss attributable to common stockholders	($73,090)	($95,393)	($67,377)
Net loss per share
Basic, net (loss) earnings per share	($0.11)	($0.14)	($0.10)
Diluted, net (loss) earnings per share	($0.11)	($0.14)	($0.10)
Weighted average number of shares outstanding
Basic, weighted average number of shares outstanding	674,832,393	663,910,194	650,214,119
Weighted Average Number of Shares Outstanding, Diluted [Abstract]
Diluted, weighted average number of shares outstanding	674,832,393	663,910,194	650,214,119

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (Loss) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Net loss	($63,919)	($88,946)	($51,031)
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustments	11,625	12,933	425
Pension liability adjustment	-1,500	0	0
Net unrealized (loss) gain during the period	-210	-175	53
Reclassification adjustment for impairment included in net loss	831	0	0
Net change in unrealized gain (loss), net	621	-175	53
Other comprehensive income	10,746	12,758	478
Comprehensive loss	-53,173	-76,188	-50,553
Comprehensive income attributable to noncontrolling interests	-8,984	-6,821	-4,702
Comprehensive loss attributable to Groupon Inc.	($62,157)	($83,009)	($55,255)

Consolidated_Statements_of_Com1

Consolidated Statements of Comprehensive Income (Loss) Condensed Consolidated Statements of Comprehensive Income (Loss) Parenthetical (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income Parenthetical [Abstract]
Tax effects for change in unrealized gain (loss)	$383	($108)	$34
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Tax	$285

Consolidated_Statements_of_Sto

Consolidated Statements of Stockholders' Equity (USD $)	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings (Accumulated Deficit) [Member]	Accumulated Other Comprehensive Income [Member]	Parent [Member]	Noncontrolling Interest [Member]	Total Equity [Member]
Beginning Balance, Equity at Dec. 31, 2011		$64,000	$1,388,253,000		($698,704,000)	$12,928,000	$702,541,000	($3,074,000)	$699,467,000
Beginning Balance, Shares, Outstanding at Dec. 31, 2011		644,145,201
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	-51,031,000				-54,773,000		-54,773,000	3,748,000	-51,025,000
Foreign currency translation adjustments	-425,000					-535,000	-535,000	960,000	425,000
Pension liability adjustment	0
Unrealized gain (loss) on available-for-sale debt security, net of tax						53,000	53,000		53,000
Adjustment of redeemable noncontrolling interests to redemption value	-12,604,000	0	-12,604,000				-12,604,000	0	-12,604,000
Common stock issued in connection with acquisition of business, shares		152,446
Purchases of additional interests in consolidated subsidiaries, shares		51,000
Shares issued to settle liability-classified awards, shares	660,539	660,539
Shares issued to settle liability-classified awards and contingent consideration	2,267,000		2,503,000				2,503,000		2,503,000
Purchase of noncontrolling interest, excess of purchase price over value of noncontrolling interest			-2,584,000				-2,584,000
Purchase of interests in consolidated subsidiaries								739,000
Purchase of noncontrolling interests in consolidated subsidiaries									-1,845,000
Exercise of stock options, shares		9,025,164
Exercise of stock options, value		1,000	9,312,000				9,313,000		9,313,000
Vesting of restricted stock units, shares		4,452,979
Tax withholding related to net share settlements of stock-based compensation awards, shares		-1,563,647
Tax withholding related to net share settlements of stock-based compensation awards, value			-14,918,000				-14,918,000		-14,918,000
Stock-based compensation on equity-classified awards			93,781,000				93,781,000		93,781,000
Excess tax benefits on stock-based compensation awards			21,263,000				21,263,000		21,263,000
Partnership distributions to noncontrolling interest holders								-4,312,000	-4,312,000
Ending Balance, Equity at Dec. 31, 2012		65,000	1,485,006,000		-753,477,000	12,446,000	744,040,000	-1,939,000	742,101,000
Ending Balance, Shares, Outstanding at Dec. 31, 2012		656,923,682
Beginning Balance, Treasury Stock, Value at Dec. 31, 2012				0
Beginning Balance, Treasury Stock, Shares at Dec. 31, 2012				0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	-88,946,000				-95,393,000		-95,393,000	6,447,000	-88,946,000
Foreign currency translation adjustments	-12,933,000					12,559,000	12,559,000	374,000	12,933,000
Pension liability adjustment	0
Unrealized gain (loss) on available-for-sale debt security, net of tax						-175,000	-175,000		-175,000
Adjustment of redeemable noncontrolling interests to redemption value	0
Common stock issued in connection with acquisition of business, shares		276,217
Common stock issued in connection with acquisition of business, net of issuance costs		0	3,051,000				3,051,000		3,051,000
Shares issued to settle liability-classified awards, shares		758,474
Shares issued to settle liability-classified awards and contingent consideration	4,649,000		4,649,000				4,649,000		4,649,000
Exercise of stock options, shares		4,003,544
Exercise of stock options, value			4,062,000				4,062,000		4,062,000
Vesting of restricted stock units, shares		15,565,805
Vesting of restricted stock units, value		2,000	-2,000
Shares issued under employee stock purchase plan, shares		774,288
Shares issued under employee stock purchase plan, value			3,241,000				3,241,000		3,241,000
Tax withholding related to net share settlements of stock-based compensation awards, shares		-5,752,058
Tax withholding related to net share settlements of stock-based compensation awards, value			-47,684,000				-47,684,000		-47,684,000
Stock-based compensation on equity-classified awards			122,222,000				122,222,000		122,222,000
Excess tax benefits on stock-based compensation awards			9,666,000				9,666,000		9,666,000
Purchases of treasury stock, shares				-4,432,800
Purchases of treasury stock, value				-46,587,000			-46,587,000		-46,587,000
Partnership distributions to noncontrolling interest holders								-6,851,000	-6,851,000
Ending Balance, Equity at Dec. 31, 2013	711,682,000	67,000	1,584,211,000		-848,870,000	24,830,000	713,651,000	-1,969,000	711,682,000
Ending Balance, Treasury Stock, Value at Dec. 31, 2013	-46,587,000			-46,587,000
Ending Balance, Treasury Stock, Shares at Dec. 31, 2013				-4,432,800
Ending Balance, Shares, Outstanding at Dec. 31, 2013		672,549,952
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	-63,919,000				-73,090,000		-73,090,000	9,171,000	-63,919,000
Foreign currency translation adjustments	-11,625,000					11,812,000	11,812,000	-187,000	11,625,000
Pension liability adjustment	-1,500,000					-1,500,000	-1,500,000	0	-1,500,000
Unrealized gain (loss) on available-for-sale debt security, net of tax						621,000	621,000		621,000
Adjustment of redeemable noncontrolling interests to redemption value	0
Common stock issued in connection with acquisition of business, shares		15,255,180
Common stock issued in connection with acquisition of business, net of issuance costs		2,000	173,813,000				173,815,000		173,815,000
Shares issued to settle liability-classified awards, shares		102,180
Shares issued to settle liability-classified awards and contingent consideration	1,041,000		1,041,000				1,041,000		1,041,000
Purchase of noncontrolling interest, excess of purchase price over value of noncontrolling interest			-6,310,000				-6,310,000
Purchase of interests in consolidated subsidiaries								2,415,000
Purchase of noncontrolling interests in consolidated subsidiaries									-3,895,000
Exercise of stock options, shares		1,029,471
Exercise of stock options, value			1,118,000				1,118,000		1,118,000
Vesting of restricted stock units, shares		17,323,096
Vesting of restricted stock units, value		1,000	-1,000
Shares issued under employee stock purchase plan, shares		857,171
Shares issued under employee stock purchase plan, value			5,396,000				5,396,000		5,396,000
Tax withholding related to net share settlements of stock-based compensation awards, shares		-5,708,990
Tax withholding related to net share settlements of stock-based compensation awards, value			-44,509,000				-44,509,000		-44,509,000
Stock-based compensation on equity-classified awards			133,230,000				133,230,000		133,230,000
Excess tax benefits on stock-based compensation awards			-569,000				-569,000		-569,000
Purchases of treasury stock, shares				-22,806,304
Purchases of treasury stock, value				-151,880,000			-151,880,000		-151,880,000
Partnership distributions to noncontrolling interest holders								-7,312,000	-7,312,000
Ending Balance, Equity at Dec. 31, 2014	764,944,000	70,000	1,847,420,000		-921,960,000	35,763,000	762,826,000	2,118,000	764,944,000
Ending Balance, Treasury Stock, Value at Dec. 31, 2014	($198,467,000)			($198,467,000)
Ending Balance, Treasury Stock, Shares at Dec. 31, 2014				-27,239,104
Ending Balance, Shares, Outstanding at Dec. 31, 2014		701,408,060

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
Income Taxes Paid	$24,006	$60,767	$126,987
Operating activities
Net loss	-63,919	-88,946	-51,031
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Depreciation and amortization of property, equipment and software	97,799	67,823	35,891
Amortization of acquired intangible assets	47,122	21,626	19,910
Stock-based compensation	122,019	121,462	104,117
Deferred income taxes	-11,106	-18,055	-7,651
Excess tax benefits on stock-based compensation	-15,980	-20,454	-27,023
Loss on equity method investments	459	44	9,925
(Gain) loss, net from changes in fair value of contingent consideration	-2,444	-3,171	897
Gain of E-Commerce transaction			-56,032
Impairment of investments	2,036	85,925	50,553
Change in assets and liabilities, net of acquisitions:
Restricted cash	6,010	2,183	-4,372
Accounts receivable	-13,660	10,989	10,534
Prepaid expenses and other current assets	78	-62,906	-70,859
Accounts payable	-11,911	-31,288	18,711
Accrued merchant and supplier payables	115,106	88,468	149,918
Accrued expenses and other current liabilities	-16,182	4,053	47,742
Other, net	33,397	40,679	35,604
Net cash provided by operating activities	288,824	218,432	266,834
Investing activities
Purchases of property and equipment and capitalized software	-88,292	-63,505	-95,836
Acquisitions of businesses, net of acquired cash	-131,463	-7,349	-46,890
Purchases of investments	-6,904	-21,982	-37,523
Settlements of liabilities related to purchase of additional interests in consolidated subsidiaries	-2,297	-1,959	0
Purchases of additional interests in consolidated subsidiaries			-14,130
Purchases of intangible assets	-500	-1,520	-600
Net cash used in investing activities	-229,456	-96,315	-194,979
Financing activities
Payments for purchases of treasury stock	-153,253	-44,840	0
Excess tax benefits on stock-based compensation	15,980	20,454	27,023
Taxes paid related to net share settlements of stock-based compensation awards	-43,618	-47,575	-12,996
Debt issuance costs	-1,029	0	0
Common stock issuance costs in connection with acquisition of business	-158	0	0
Payments of contingent consideration from acquisitions	0	-4,289	-4,700
Settlements of purchase price obligations related to acquisitions	-3,136	-5,000	-2,233
Proceeds from stock option exercises and employee stock purchase plan	6,514	7,303	9,313
Partnership distribution payments to noncontrolling interest holders	-8,034	-6,130	-4,312
Payments of capital lease obligations	-7,422	-1,620	0
Net cash (used in) provided by financing activities	-194,156	-81,697	12,095
Effect of exchange rate changes on cash and cash equivalents	-33,771	-9,237	2,404
Net (decrease) increase in cash and cash equivalents	-168,559	31,183	86,354
Cash and cash equivalents, beginning of period	1,240,472	1,209,289	1,122,935
Cash and cash equivalents, end of period	1,071,913	1,240,472	1,209,289
Non-cash investing and financing activities
Issuance of common stock in connection with acquisition of business	173,972	3,051	0
Contingent consideration liabilities incurred in connection with acquisitions	4,388	3,567	3,400
Equipment acquired under capital lease obligations	36,574	10,001	1,122
Shares issued to settle liability-classified awards and contingent consideration	1,041	4,649	2,267
Liability for purchases of treasury stock	374	1,747	0
Liability for purchase of additional interests in consolidated subsidiaries	1,598	0	1,959
Accounts payable and accrued expenses related to purchases of property and equipment and capitalized software	2,109	1,564	1,891
Contribution of investment in E-Commerce transaction			47,042
Stock issued in exchange for additional interests in consolidated subsidiaries			527
Shares issued to settle contingent consideration			$236

Description_of_Business_and_Ba

Description of Business and Basis of Presentation	12 Months Ended
	Dec. 31, 2014
DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION [Abstract]
Description of Business and Basis of Presentation [Text Block]	DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION
	Company Information
	Groupon, Inc. and subsidiaries (the "Company"), which commenced operations in October 2008, operates online local commerce marketplaces throughout the world that connect merchants to consumers by offering goods and services at a discount. The Company also offers deals on products for which it acts as the merchant of record. Customers can access the Company's deal offerings directly through its websites and mobile applications and indirectly using search engines. The Company also sends emails to its subscribers with deal offerings that are targeted by location and personal preferences.
	The Company's operations are organized into three segments: North America, EMEA, which is comprised of Europe, Middle East and Africa, and the remainder of the Company's international operations ("Rest of World"). See Note 16 "Segment Information."

Summary_of_Significant_Account

Summary of Significant Accounting Policies (Notes)	12 Months Ended
	Dec. 31, 2014
Summary of Significant Accounting Policies [Abstract]
Significant Accounting Policies [Text Block]	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
	Principles of Consolidation
	The consolidated financial statements include the accounts of the Company and its subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. The Company's consolidated financial statements were prepared in accordance with U.S. generally accepted accounting principles ("U.S. GAAP") and include the assets, liabilities, revenue and expenses of all wholly‑owned subsidiaries and majority‑owned subsidiaries over which the Company exercises control and variable interest entities for which the Company has determined that it is the primary beneficiary. Outside stockholders' interests in subsidiaries are shown on the consolidated financial statements as "Noncontrolling interests." Equity investments in entities in which the Company does not have a controlling financial interest are accounted for under either the equity method, the cost method or as available-for-sale securities, as appropriate.
	Reclassifications
	Certain reclassifications have been made to the consolidated financial statements of prior years and the accompanying notes to conform to the current year presentation.
	Use of Estimates
	The preparation of consolidated financial statements in conformity with U.S. GAAP requires estimates and assumptions that affect the reported amounts and classifications of assets and liabilities, revenue and expenses, and the related disclosures of contingent liabilities in the consolidated financial statements and accompanying notes. Estimates are utilized for, but not limited to, stock‑based compensation, income taxes, valuation of acquired goodwill and intangible assets, investments, customer refunds, contingent liabilities and the useful lives of property, equipment and software and intangible assets. Actual results could differ materially from those estimates.
	Cash and Cash Equivalents
	The Company considers all highly‑liquid investments with an original maturity of three months or less from the date of purchase to be cash equivalents. The Company's cash equivalents primarily include holdings in money market funds and overnight securities.
	Accounts Receivable, Net
	Accounts receivable primarily represents the net cash due from the Company's credit card and other payment processors for cleared transactions. The carrying amount of the Company's receivables is reduced by an allowance for doubtful accounts that reflects management's best estimate of amounts that will not be collected. The allowance is based on historical loss experience and any specific risks identified in collection matters. Accounts receivable are charged off against the allowance for doubtful accounts when it is determined that the receivable is uncollectible. The Company's allowance for doubtful accounts as of December 31, 2014 and 2013 was $2.2 million and $0.7 million, respectively. Bad debt expense for the years ended December 31, 2014, 2013 and 2012 was $2.3 million, $0.7 million and $0.6 million, respectively.
	Inventories
	Inventories, consisting of merchandise purchased for resale, are accounted for using the first-in-first-out ("FIFO") method of accounting and are valued at the lower of cost or market value. The Company writes down its inventory for estimated obsolescence and to the lower of cost or market value based upon assumptions about future demand and market conditions. If actual market conditions are less favorable than those projected by management, additional inventory write-downs may be required. Once established, the original cost of the inventory less the related inventory allowance represents a new cost basis.
	Restricted Cash
	The Company had $12.0 million and $5.2 million of restricted cash recorded within "Prepaid expenses and other current assets" and "Other non-currents assets," respectively, as of December 31, 2014. The Company had $14.6 million and $0.4 million of restricted cash recorded within "Prepaid expenses and other current assets" and "Other non-currents assets," respectively, as of December 31, 2013. Restricted cash primarily represents amounts that the Company is unable to access for operational purposes pursuant to contractual arrangements with certain financial institutions and with entities that process merchant payments on the Company's behalf.
	Internal-Use Software
	The Company incurs costs related to internal-use software and website development, including purchased software and internally-developed software. Costs incurred in the planning and evaluation stage of internally-developed software and website development are expensed as incurred. Costs incurred and accumulated during the application development stage are capitalized and included within "Property, equipment and software, net" on the consolidated balance sheets. Capitalized internally-developed software and website development costs are amortized over their expected economic life of two years using the straight-line method.
	Goodwill
	Goodwill is allocated to the Company's reporting units at the date the goodwill is initially recorded. Once goodwill has been allocated to the reporting units, it no longer retains its identification with a particular acquisition and becomes identified with the reporting unit in its entirety. Accordingly, the fair value of the reporting unit as a whole is available to support the recoverability of its goodwill.
	The Company evaluates goodwill for impairment annually on October 1 or more frequently when an event occurs or circumstances change that indicates the carrying value may not be recoverable. The Company has the option to assess goodwill for impairment by first performing a qualitative assessment to determine whether it is more-likely-than-not that the fair value of a reporting unit is less than its carrying amount. If the Company determines that it is not more-likely-than-not that the fair value of a reporting unit is less than its carrying amount, then further goodwill impairment testing is not required to be performed. If the Company determines that it is more-likely-than-not that the fair value of a reporting unit is less than its carrying amount, or if the Company does not elect the option to perform an initial qualitative assessment, the Company is required to perform a two-step goodwill impairment test. In the first step, the fair value of the reporting unit is compared to its book value including goodwill. If the fair value of the reporting unit is in excess of its book value, the related goodwill is not impaired and no further analysis is necessary. If the fair value of the reporting unit is less than its book value, there is an indication of potential impairment and a second step is performed. When required, the second step of testing involves calculating the implied fair value of goodwill for the reporting unit. The implied fair value of goodwill is determined in the same manner as goodwill recognized in a business combination, which is the excess of the fair value of the reporting unit determined in step one over the fair value of its net assets and identifiable intangible assets as if the reporting unit had been acquired. If the carrying value of the reporting unit's goodwill exceeds the implied fair value of that goodwill, an impairment loss is recognized in an amount equal to that excess. For reporting units with a negative book value (i.e., excess of liabilities over assets), qualitative factors are evaluated to determine whether it is necessary to perform the second step of the goodwill impairment test.
	Impairment of Long-Lived Assets
	Long‑lived assets, such as property, equipment and software and intangible assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset or asset group may not be recoverable. If circumstances require that a long‑lived asset or asset group be tested for possible impairment, the Company first compares the undiscounted cash flows expected to be generated by that long-lived asset or asset group to its carrying amount. If the carrying amount of the long‑lived asset or asset group is not recoverable on an undiscounted cash flow basis, an impairment is recognized to the extent that the carrying amount exceeds its fair value.
	Investments
	Investments in nonmarketable equity shares with no redemption provisions that are not common stock or in-substance common stock or for which the Company does not have the ability to exercise significant influence are accounted for using the cost method of accounting and classified within "Investments" on the consolidated balance sheets. Under the cost method of accounting, investments are carried at cost and are adjusted only for other-than-temporary declines in fair value, certain distributions and additional investments.
	Investments in common stock or in-substance common stock for which the Company has the ability to exercise significant influence are accounted for under the equity method and classified within "Investments" on the consolidated balance sheets. The Company's proportionate share of income or loss on equity method investments is presented within "Other expense, net" on the consolidated statements of operations.
	The Company has investments in convertible debt securities and convertible redeemable preferred shares issued by nonpublic entities and has categorized these investments as available-for-sale securities, which are classified within "Investments" on the consolidated balance sheets. Available-for-sale securities are recorded at fair value each reporting period. Unrealized gains and losses, net of the related tax effects, are excluded from earnings and recorded as a separate component within "Accumulated other comprehensive income" on the consolidated balance sheets until realized. Interest income is reported within "Other expense, net" on the consolidated statements of operations.
	Other-than-Temporary Impairment of Investments
	An unrealized loss exists when the current fair value of an investment is less than its amortized cost basis. The Company conducts reviews of its investments with unrealized losses on a quarterly basis to evaluate whether those impairments are other-than-temporary. This evaluation, which is performed at the individual investment level, consists of several qualitative and quantitative factors regarding the severity and duration of the unrealized loss as well as the Company's intent and ability to hold the investment for a period of time that is sufficient to allow for an anticipated recovery in value. Evidence considered in this evaluation includes the amount of the impairment, the length of time that the investment has been impaired, the factors contributing to the impairment, the financial condition and near-term prospects of the investee, recent operating trends and forecasted performance of the investee, market conditions in the geographic area or industry in which the investee operates, and the Company's strategic plans for holding the investment in relation to the period of time expected for an anticipated recovery in value. Additionally, the Company considers whether it intends to sell the investment or whether it is more-likely-than-not that the Company will be required to sell the investment before recovery of the amortized cost basis. Investments with unrealized losses that are determined to be other-than-temporary are written down to fair value with a charge to earnings. Unrealized losses that are determined to be temporary in nature are not recorded for cost method investments and equity method investments, while such losses are recorded, net of tax, in accumulated other comprehensive income for available-for-sale securities.
	Income Taxes
	The provision for income taxes is determined using the asset and liability method. Under this method, deferred tax assets and liabilities are calculated based upon the temporary differences between the financial statement and income tax bases of assets and liabilities using the enacted tax rates that are applicable in a given year. The deferred tax assets are recorded net of a valuation allowance when, based on the weight of available evidence, the Company believes it is more-likely-than-not that some portion or all of the recorded deferred tax assets will not be realized in future periods. The Company considers many factors when assessing the likelihood of future realization of its deferred tax assets, including recent cumulative earnings experience, expectations of future taxable income and capital gains by taxing jurisdiction, the carry‑forward periods available for tax reporting purposes, the ability to carryback losses and other relevant factors. The Company allocates its valuation allowance to current and non-current deferred tax assets on a pro-rata basis. A change in the estimate of future taxable income may require an increase or decrease to the valuation allowance.
	The Company utilizes a two-step approach to recognizing and measuring uncertain tax positions. The first step is to evaluate the tax position for recognition by determining if the weight of available evidence indicates it is more-likely-than-not that the position will be sustained on audit, including resolution of related appeals or litigation processes. The second step is to measure the tax benefit as the largest amount which is more than 50% likely of being realized upon ultimate settlement. The Company includes interest and penalties related to uncertain tax positions within "Provision for income taxes" on the consolidated statements of operations. See Note 12 "Income Taxes."
	Lease and Asset Retirement Obligations
	The Company categorizes leases at their inception as either operating or capital leases and may receive renewal or expansion options, rent holidays, and leasehold improvement and other incentives on certain lease agreements. The Company recognizes lease costs on a straight-line basis, taking into account adjustments for free or escalating rental payments and deferred payment terms. Additionally, lease incentives are accounted for as a reduction of lease costs over the term of the agreement. Leasehold improvements are capitalized at cost and amortized over the shorter of their useful life or the non-cancellable term of the lease. The Company records rent expense associated with operating lease obligations primarily within "Selling, general and administrative" on the consolidated statements of operations.
	The Company establishes assets and liabilities for the present value of estimated future costs to retire long-lived assets at the termination or expiration of a lease. Such assets are amortized over the lease term, and the recorded liabilities are accreted to the future value of the estimated retirement costs. The related amortization and accretion expenses are presented within "Selling, general and administrative" on the consolidated statements of operations.
	Revenue Recognition
	The Company recognizes revenue when the following criteria are met: persuasive evidence of an arrangement exists; delivery has occurred; the selling price is fixed or determinable; and collection is reasonably assured.
	Third party revenue recognition
	The Company generates third party revenue, where it acts as a third party marketing agent, by offering goods and services provided by third party merchants at a discount through its online local commerce marketplaces that connect merchants to consumers. The Company's marketplaces include deals offered through a variety of categories including: Local, Goods and Travel. Customers purchase the discount vouchers ("Groupons") from the Company and redeem them with the Company's merchants.
	The revenue recognition criteria are met when the customer purchases a deal, the Groupon has been electronically delivered to the purchaser and a listing of Groupons sold has been made available to the merchant. At that time, the Company's obligations to the merchant, for which it is serving as a marketing agent, are substantially complete. The Company's remaining obligations, which are limited to remitting payment to the merchant and continuing to make available on the Company's website information about Groupons sold that was previously provided to the merchant, are inconsequential or perfunctory. For a portion of the hotel deals offered through the Company's online local marketplaces, the Company facilitates the booking of rooms by taking reservations through its websites. Such reservations are generally cancelable at any time prior to check-in and the Company defers the revenue on those deals until the customer's stay occurs.
	.    The Company records as revenue the net amount it retains from the sale of Groupons after deducting the portion of the purchase price that is payable to the featured merchant, excluding applicable taxes and net of estimated refunds for which the merchant's share is recoverable. Revenue is presented on a net basis because the Company is acting as a marketing agent of the merchant in the transaction.
	For merchant payment arrangements that are structured under a redemption model, merchants are not paid until the customer redeems the Groupon that has been purchased. If a customer does not redeem the Groupon under this payment model, the Company retains all the gross billings. The Company recognizes incremental revenue from unredeemed Groupons and derecognizes the related accrued merchant payable when its legal obligation to the merchant expires, which the Company believes is shortly after deal expiration in most jurisdictions that have payment arrangements structured under a redemption model.
	Direct revenue recognition
	The Company evaluates whether it is appropriate to record the gross amount of its sales and related costs by considering a number of factors, including, among other things, whether the Company is the primary obligor under the arrangement, has inventory risk and has latitude in establishing prices. Direct revenue is derived primarily from selling consumer products through the Company's Goods category where the Company is the merchant of record. The Company is the primary obligor in these transactions, is subject to general inventory risk and has latitude in establishing prices. Accordingly, direct revenue is presented on a gross basis, excluding applicable taxes and net of estimated refunds. Direct revenue, including associated shipping revenue, is recognized when title passes to the customer upon delivery of the product.
	Other revenue recognition
	Advertising revenue is recognized when the advertiser's logo or website link has been included on the Company's websites or in specified email distributions for the requisite period of time as set forth in the agreement with the advertiser. Commission revenue is earned when customers make purchases with retailers using coupons accessed through the Company's websites and mobile applications. Revenue from payment processing is earned on a per transaction basis. The Company recognizes revenue from those activities when the underlying transactions are completed. Revenue from point of sale solutions is recognized on a subscription basis over the term of the arrangement with the merchant.
	Discounts
	The Company provides discount offers to encourage purchases of goods and services through its marketplaces. The Company records discounts as a reduction of revenue.
	Cost of revenue
	Cost of revenue is comprised of direct and certain indirect costs incurred to generate revenue. For direct revenue transactions, cost of revenue includes the cost of inventory, shipping and fulfillment costs and inventory markdowns. Fulfillment costs are comprised of third party logistics provider costs, as well as rent, depreciation, personnel costs and other costs of operating the Company's fulfillment center, which began operations in the fourth quarter of 2013. For third party revenue transactions, cost of revenue includes estimated refunds for which the merchant's share is not recoverable. Other costs incurred to generate revenue, which include credit card processing fees, editorial costs, certain technology costs, web hosting and other processing fees, are allocated to cost of third party revenue, direct revenue and other revenue in proportion to gross billings during the period.
	Technology costs within cost of revenue consist of a portion of the payroll and stock‑based compensation expense related to the Company's technology support personnel who are responsible for operating and maintaining the infrastructure of the Company's websites. Technology costs also include a portion of amortization expense from internal-use software, primarily related to website development. Remaining technology costs within cost of revenue include email distribution costs. Editorial costs included in cost of revenue consist of payroll and stock‑based compensation expense related to the Company's editorial personnel, as these staff members are primarily dedicated to drafting and promoting deals.
	Refunds
	The Company estimates future refunds utilizing a statistical model that incorporates the following data inputs and factors: historical refund experience developed from millions of deals featured on the Company's websites and mobile applications, the relative risk of refunds based on expiration date, deal value, deal category and other qualitative factors that could impact the level of future refunds, such as introductions of new deals, discontinuations of legacy deals and expected changes, if any, in Company practices in response to refund experience or economic trends that might impact customer demand. The portion of customer refunds for which the merchant's share is not recoverable on third party revenue deals is estimated based on the refunds that are expected to be issued after expiration of the related vouchers, the refunds that are expected to be issued due to the merchant bankruptcy or poor customer experience, and whether the payment terms of the related merchant contracts are structured using a redemption payment model or a fixed payment model.
	The Company accrues costs associated with refunds within "Accrued expenses" on the consolidated balance sheets. The cost of refunds for third party revenue where the amounts payable to the merchant are recoverable and for all direct revenue is presented on the consolidated statements of operations as a reduction to revenue. The cost of refunds for third party revenue for which the merchant's share is not recoverable is presented as a cost of revenue.
	The Company assesses the trends that could affect its estimates on an ongoing basis and makes adjustments to the refund reserve calculations if it appears that changes in circumstances, including changes to the Company's refund policies, may cause future refunds to differ from its original estimates. If actual results are not consistent with the estimates or assumptions stated above, the Company may need to change its future estimates, and the effects could be material to the consolidated financial statements.
	Customer Credits
	The Company issues credits to its customers that can be applied against future purchases through its online marketplaces for certain qualifying acts, such as referring new customers, and also to satisfy refund requests. The Company has recorded its customer credit obligations within "Accrued expenses" on the consolidated balance sheets (See Note 7 "Supplemental Consolidated Balance Sheet and Statements of Operations Information"). Customer credit obligations incurred for new customer referrals or other qualifying acts are expensed as incurred and are classified within "Marketing" on the consolidated statements of operations. Customer credits issued to satisfy refund requests are applied as a reduction to the refunds reserve.
	Stock‑Based Compensation
	The Company measures stock‑based compensation cost at fair value, net of estimated forfeitures. Expense is generally recognized on a straight-line basis over the service period during which awards are expected to vest, except for awards with performance conditions, which are recognized using the accelerated method. The Company includes stock-based compensation expense within "Cost of revenue," "Marketing" and "Selling, general and administrative," consistent with the respective employees' cash compensation, on the consolidated statements of operations. See Note 11 "Compensation Arrangements."
	Foreign Currency
	Balance sheet accounts of the Company's operations outside of the U.S. are translated from foreign currencies into U.S. dollars at the exchange rates as of the consolidated balance sheet dates. Revenue and expenses are translated at average exchange rates during the period. Foreign currency translation adjustments and foreign currency gains and losses on intercompany balances that are of a long-term investment nature are included within "Accumulated other comprehensive income" on the consolidated balance sheets. Foreign currency gains and losses resulting from transactions which are denominated in currencies other than the entity's functional currency, including foreign currency gains and losses on intercompany balances that are not of a long-term investment nature, are included within "Other expense, net" on the consolidated statements of operations. For the years ended December 31, 2014, 2013 and 2012, the Company had $31.5 million of foreign currency transaction losses, $10.3 million of foreign currency transaction losses and $1.4 million of foreign currency transaction gains, respectively.
	Recently Issued Accounting Standards
	In May 2014, the Financial Accounting Standards Board issued Accounting Standards Update ("ASU") 2014-09, Revenue from Contracts with Customers. This ASU is a comprehensive new revenue recognition model that requires a company to recognize revenue to depict the transfer of goods or services to a customer at an amount that reflects the consideration it expects to receive in exchange for those goods or services. The ASU is effective for annual periods beginning after December 15, 2016 and interim periods within those annual periods. The Company is still assessing the impact of adoption on its consolidated financial statements.
	There are no additional accounting standards that have been issued but not yet adopted that the Company believes will have a material impact on its consolidated financial position or results of operations.

Business_Combinations_and_Acqu

Business Combinations and Acquisitions of Noncontrolling Interests	12 Months Ended
	Dec. 31, 2014
Business Combinations [Abstract]
Business Combinations and Acquisitions of Noncontrolling Interests Disclosure [Text Block]	BUSINESS COMBINATIONS AND ACQUISITIONS OF NONCONTROLLING INTERESTS
	2014 Acquisition Activity
	The Company acquired six businesses during the year ended December 31, 2014.  Business combinations are accounted for using the acquisition method, and the results of acquired businesses are included in the consolidated financial statements beginning on the respective acquisition dates. The fair value of consideration transferred in business combinations is allocated to the tangible and intangible assets acquired and liabilities assumed at the acquisition date, with the remaining unallocated amount recorded as goodwill. The allocations of the acquisition price for recent acquisitions have been prepared on a preliminary basis, and changes to those allocations may occur as a result of final working capital adjustments and tax return filings. Acquired goodwill represents the premium the Company paid over the fair value of the net tangible and intangible assets acquired. The Company paid these premiums for a number of reasons, including growing the Company's merchant and customer base, acquiring assembled workforces, expanding its presence in international markets, expanding and advancing its product offerings and enhancing technology capabilities. The goodwill from these business combinations is generally not deductible for tax purposes.
	For the years ended December 31, 2014 and 2013, $3.7 million and $3.2 million of external transaction costs related to business combinations, primarily consisting of legal and advisory fees, are classified within "Acquisition-related expense (benefit), net" on the consolidated statements of operations, respectively. Such costs were not material for the year ended December 31, 2012.
	LivingSocial Korea, Inc.
	On January 2, 2014, the Company acquired all of the outstanding equity interests of LivingSocial Korea, Inc., a Korean corporation and holding company of Ticket Monster Inc. ("Ticket Monster"). Ticket Monster is an e-commerce company based in the Republic of Korea that connects merchants to consumers by offering goods and services at a discount. The primary purpose of this acquisition was to grow the Company's merchant and customer base and expand its presence in the Korean e-commerce market. The aggregate acquisition-date fair value of the consideration transferred for the Ticket Monster acquisition totaled $259.4 million, which consisted of the following (in thousands):
	Cash		$	96,496
	Issuance of 13,825,283 shares of Class A common stock		162,862
	Total		$	259,358
	The fair value of the Class A Common Stock issued as consideration was measured based on the stock price upon closing of the transaction on January 2, 2014.
	The following table summarizes the allocation of the aggregate acquisition price of the Ticket Monster acquisition (in thousands):
	Cash and cash equivalents	$	24,768
	Accounts receivable	17,732
	Deferred income taxes	1,264
	Prepaid expenses and other current assets	829
	Property, equipment and software	5,944
	Goodwill	218,692
	Intangible assets:(1)
	Subscriber relationships	57,022
	Merchant relationships	32,176
	Developed technology	571
	Trade name	19,325
	Other non-current assets	3,033
	Total assets acquired	$	381,356
	Accounts payable	$	5,951
	Accrued merchant and supplier payables	82,934
	Accrued expenses	22,700
	Other current liabilities	3,482
	Deferred income taxes, non-current	1,264
	Other non-current liabilities	5,667
	Total liabilities assumed	$	121,998
	Total acquisition price	$	259,358
	-1	The estimated useful lives of the acquired intangible assets are 5 years for subscriber relationships, 3 years for merchant relationships, 2 years for developed technology and 5 years for trade name.
	Ideeli, Inc.
	On January 13, 2014, the Company acquired all of the outstanding equity interests of Ideeli, Inc. (d/b/a "Ideel"), a fashion flash site based in the United States. The primary purpose of this acquisition was to expand and advance the Company's product offerings. The aggregate acquisition-date fair value of the consideration transferred for the Ideel acquisition totaled $42.7 million in cash.
	The following table summarizes the allocation of the aggregate acquisition price of the Ideel acquisition (in thousands):
	Cash and cash equivalents	$	79
	Accounts receivable	988
	Deferred income taxes	640
	Prepaid expenses and other current assets	22,081
	Property, equipment and software	8,173
	Goodwill	4,203
	Intangible assets:(1)
	Subscriber relationships	5,490
	Brand relationships	7,100
	Trade name	4,500
	Deferred income taxes, non-current	8,877
	Total assets acquired	$	62,131
	Accounts payable	$	1,640
	Accrued supplier payables	4,092
	Accrued expenses	9,118
	Other current liabilities	482
	Deferred income taxes, non-current	348
	Other non-current liabilities	3,753
	Total liabilities assumed	$	19,433
	Total acquisition price	$	42,698
	-1	The estimated useful lives of the acquired intangible assets are 3 years for subscriber relationships, 5 years for brand relationships and 5 years for trade name.
	Other Acquisitions
	The Company acquired four other businesses during the year ended December 31, 2014. The primary purpose of these acquisitions was to acquire an experienced workforce, expand and advance product offerings and enhance technology capabilities. The aggregate acquisition-date fair value of the consideration transferred for these acquisitions totaled $32.9 million, which consisted of the following (in thousands):
	Cash		$	17,364
	Issuance of 1,429,897 shares of Class A common stock		11,110
	Contingent consideration		4,388
	Total		$	32,862
	The fair value of the Class A Common Stock issued as consideration for one of the acquisitions was measured based on the stock price upon closing of the related transaction on November 13, 2014.
The following table summarizes the allocation of the aggregate purchase price of these other acquisitions (in thousands):
Net working capital (including acquired cash of $0.2 million)		$	(396	)
Goodwill		27,150
Intangible assets: (1)
Subscriber relationships		2,555
Developed technology		3,372
Brand relationships		579
Deferred income taxes, non-current		(398		)
Total purchase price		$	32,862
-1	Acquired intangible assets have estimated useful lives of between 1 and 5 years.
Pro forma results of operations presented below do not include the results of these other acquisitions because the effects of these acquisitions, individually and in the aggregate, were not material to the Company's consolidated results of operations.
Pro Forma Financial Information
The following unaudited pro forma information presents the combined operating results of the Company for the year ended December 31, 2013, as if the Company had acquired Ticket Monster and Ideel as of January 1, 2013 (in thousands). Pro forma results of operations have not been presented for the year ended December 31, 2014, because the operating results of Ticket Monster and Ideel from January 1, 2014 through their respective acquisition dates were not material to the Company's consolidated results of operations for the year ended December 31, 2014. The underlying pro forma results include the historical financial results of the Company and these two acquired businesses adjusted for depreciation and amortization expense associated with the assets acquired. The unaudited pro forma results do not reflect any operating efficiencies or potential cost savings which may result from the consolidation of the operations of the Company and the acquired entities. Accordingly, these unaudited pro forma results are not necessarily indicative of what the actual results of operations of the combined company would have been if the acquisitions had occurred as of January 1, 2013, nor are they indicative of future results of operations.
	Year Ended
	December 31, 2013
Revenue	$	2,763,639
Net loss	(217,613		)
The revenue and net loss of Ticket Monster included in our consolidated statements of operations were $149.6 million and $45.4 million, respectively, for the year ended December 31, 2014. The revenue and net loss of Ideel included in our consolidated statements of operations were $82.4 million and $12.3 million, respectively, for the year ended December 31, 2014.
2013 Acquisition Activity
The primary purpose of the Company's seven acquisitions during the year ended December 31, 2013 was to enhance the Company's technology capabilities, acquire experienced workforces and expand and advance product offerings. The aggregate acquisition-date fair value of the consideration transferred for these acquisitions totaled $16.1 million, which consisted of the following (in thousands):
Cash		$	9,459
Issuance of Class A common stock		3,051
Contingent consideration		3,567
Total		$	16,077
The following table summarizes the allocation of the aggregate acquisition price of acquisitions for the year ended December 31, 2013 (in thousands):
Net working capital (including acquired cash of $2.1 million)		$	1,728
Property and equipment		99
Goodwill		9,504
Intangible assets: (1)
Subscriber relationships		1,928
Merchant relationships		757
Developed technology		2,742
Other intangible assets		50
Net deferred tax liabilities		(731		)
Total acquisition price		$	16,077
-1	Acquired intangible assets have estimated useful lives of between 1 and 5 years.
Pro forma results of operations have not been presented because the effects of these business combinations, individually and in the aggregate, were not material to the Company's consolidated results of operations.
2012 Acquisition Activity
The primary purpose of the Company's ten acquisitions during the year ended December 31, 2012 was to enhance the Company's technology and marketing capabilities and to expand and advance product offerings. The aggregate acquisition-date fair value of the consideration transferred for these acquisitions totaled $54.9 million, which consisted of the following (in thousands):
Cash		$	49,013
Purchase price obligations		2,485
Contingent consideration		3,400
Total		$	54,898
The following table summarizes the allocation of the aggregate acquisition price of acquisitions for the year ended December 31, 2012 (in thousands):
Net working capital (including acquired cash of $2.1 million)		$	1,750
Property and equipment		165
Goodwill		39,170
Intangible assets:(1)
Subscriber relationships		170
Merchant relationships		1,500
Developed technology		14,350
Net deferred tax liabilities		(2,207		)
Total acquisition price		$	54,898
-1	Acquired intangible assets have estimated useful lives of between 1 and 5 years.
Pro forma results of operations have not been presented because the effects of these business combinations, individually and in the aggregate, were not material to the Company's consolidated results of operations.
Purchases of Additional Interests in Consolidated Subsidiaries
During the year ended December 31, 2014, the Company acquired additional interests in majority-owned subsidiaries for an aggregate acquisition price of $3.9 million. Cash consideration of $2.3 million was paid in 2014 and the remaining amounts of $1.0 million and $0.6 million are included within other current liabilities and other non-current liabilities, respectively, on the consolidated balance sheet as of December 31, 2014.
During the year ended December 31, 2012, the Company acquired additional interests in majority-owned subsidiaries for an aggregate acquisition price of $16.7 million, including $16.1 million of cash consideration and $0.6 million of Class A common stock. Cash consideration of $14.1 million was paid in 2012 and the remaining $2.0 million was paid in 2013. Additionally, in connection with these transactions, certain liability-classified subsidiary stock-based compensation awards were settled in exchange for $15.2 million of cash, $2.3 million of Class A common stock and $10.5 million of deferred compensation that was subsequently recognized as compensation expense over service periods of between one and two years. Cash settlements of $14.0 million were paid in 2012, and the remaining $1.2 million was paid in 2013.

Property_Equipment_and_Softwar

Property, Equipment and Software, Net (Notes)	12 Months Ended
	Dec. 31, 2014
Property, Equipment and Software, Net [Abstract]
Property, Equipment and Software Disclosure [Text Block]	PROPERTY, EQUIPMENT AND SOFTWARE, NET
	The following summarizes the Company's property, equipment and software, net (in thousands):
			December 31,
			2014			2013
	Warehouse equipment		$	4,859		$	3,997
	Furniture and fixtures		18,610			13,526
	Leasehold improvements		39,900			35,830
	Office and telephone equipment		4,448			5,062
	Purchased software		40,448			22,499
	Computer hardware(1)		135,731			84,673
	Internally-developed software		133,598			79,113
	Total property, equipment and software, gross		377,594			244,700
	Less: accumulated depreciation and amortization		(195,119		)	(110,277		)
	Property, equipment and software, net		$	182,475		$	134,423
	-1	Includes computer hardware acquired under capital leases of $48.0 million and $11.8 million as of December 31, 2014 and 2013, respectively.
	Property, equipment and software are stated at cost and assets under capital leases are stated at the present value of minimum lease payments. Depreciation expense is recorded on a straight-line basis over the estimated useful lives of the assets (generally three years for computer hardware, purchased software and office and telephone equipment, five to ten years for furniture and fixtures and warehouse equipment, and the shorter of the term of the lease or the asset's useful life for leasehold improvements) and is primarily classified within "Selling, general and administrative" on the consolidated statements of operations. Depreciation and amortization expense on property, equipment and software, including internally-developed software, was $97.8 million, $67.8 million and $35.9 million for the years ended December 31, 2014, 2013 and 2012, respectively. These amounts include amortization expense of $7.2 million and $2.1 million on assets under capital leases for the years ended December 31, 2014 and 2013, respectively. Amortization expense recognized for assets under capital leases was not material for the year ended December 31, 2012. See Note 8, "Commitments and Contingencies" for further detail regarding capital leases.
	As of December 31, 2014 and 2013, the carrying amount of internally-developed software, net of accumulated amortization, was $61.8 million and $47.9 million, respectively. Amortization expense for capitalized internally-developed software was $42.1 million, $25.2 million and $3.4 million for the years ended December 31, 2014, 2013 and 2012, respectively. For the year ended December 31, 2014, $11.7 million and $30.4 million of amortization expense for capitalized internally-developed software is included within "Cost of revenue" and "Selling, general and administrative," respectively, on the consolidated statements of operations. For the year ended December 31, 2013, $7.9 million and $17.3 million of amortization expense for capitalized internally-developed software is included within "Cost of revenue" and "Selling, general and administrative," respectively, on the consolidated statements of operations. For the year ended December 31, 2012, amortization expense for capitalized internally-developed software is primarily included within "Selling, general and administrative."

Goodwill_and_Other_Intangible_

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2014
GOODWILL AND OTHER INTANGIBLE ASSETS [Abstract]
Goodwill and Intangible Assets Disclosure [Text Block]	GOODWILL AND OTHER INTANGIBLE ASSETS
	The following table summarizes the Company's goodwill activity by segment for the years ended December 31, 2014 and 2013 (in thousands):
			North America			International			EMEA			Rest of World			Consolidated
	Balance as of December 31, 2012		$	79,276		$	127,408		$	—		$	—		$	206,684
	Reallocation to new segments		—			(124,770		)	105,347			19,423			—
	Goodwill related to acquisitions		4,893			—			4,611			—			9,504
	Other adjustments(1)		1,288			(2,638		)	5,711			278			4,639
	Balance as of December 31, 2013		$	85,457		$	—		$	115,669		$	19,701		$	220,827
	Goodwill related to acquisitions		31,353			—			—			218,692			250,045
	Other adjustments(1)		(92		)	—			(13,490		)	(9,480		)	(23,062		)
	Balance as of December 31, 2014		$	116,718		$	—		$	102,179		$	228,913		$	447,810
	-1	Represents the impact of changes in foreign exchange rates on goodwill.
	The Company evaluates goodwill for impairment annually on October 1 or more frequently when an event occurs or circumstances change that indicates the carrying value may not be recoverable. No goodwill impairments were recognized for the years ended December 31, 2014, 2013 and 2012.
	The following tables summarize the Company's intangible assets (in thousands):
			31-Dec-14
	Asset Category		Gross Carrying Value			Accumulated Amortization			Net Carrying Value
	Subscriber relationships		$	103,858		$	48,754		$	55,104
	Merchant relationships		39,448			18,677			20,771
	Trade names		29,190			10,666			18,524
	Developed technology		25,903			21,989			3,914
	Brand relationships		7,664			1,486			6,178
	Other intangible assets		17,045			10,979			6,066
	Total		$	223,108		$	112,551		$	110,557
			31-Dec-13
	Asset Category		Gross Carrying Value			Accumulated Amortization			Net Carrying Value
	Subscriber relationships		$	45,541		$	30,866		$	14,675
	Merchant relationships		9,186			7,991			1,195
	Trade names		6,739			6,739			—
	Developed technology		23,038			19,547			3,491
	Other intangible assets		16,776			7,694			9,082
	Total		$	101,280		$	72,837		$	28,443
	Amortization of intangible assets is computed using the straight-line method over their estimated useful lives, which range from 1 to 5 years. Amortization expense related to intangible assets was $47.1 million, $21.6 million and $19.9 million for the years ended December 31, 2014, 2013 and 2012, respectively. As of December 31, 2014, the Company's estimated future amortization expense related to intangible assets is as follows (in thousands):
	Years Ended December 31,
	2015		$	40,495
	2016		33,707
	2017		18,653
	2018		17,617
	2019		85
	Thereafter		—
	Total		$	110,557

Investments

Investments	12 Months Ended
	Dec. 31, 2014
Investments, All Other Investments [Abstract]
Cost and Equity Method Investments Disclosure [Text Block]	INVESTMENTS
	The following table summarizes the Company's investments (dollars in thousands):
		31-Dec-14		Percent Ownership of Voting Stock						December 31, 2013				Percent Ownership of Voting Stock
	Cost and equity method investments:
	Cost method investments	$	15,630	6	%	to	19	%		$	15,788			6	%	to	19	%
	Equity method investments	1,231		21	%	to	50	%		1,690				21	%	to	50	%
	Total cost and equity method investments	16,861								17,478
	Available-for-sale securities:
	Convertible debt securities	2,527								3,174
	Redeemable preferred shares	4,910		17	%	to	19	%		—				19	%
	Total available-for-sale securities	7,437								3,174
	Total investments	$	24,298							$	20,652
	The following table summarizes the amortized cost, gross unrealized gain, gross unrealized loss and fair value of the Company's available-for-sale securities as of December 31, 2014 and 2013, respectively (in thousands):
		31-Dec-14														December 31, 2013
		Amortized Cost		Gross Unrealized Gain				Gross Unrealized Loss				Fair Value				Amortized Cost			Gross Unrealized Gain		Gross Unrealized Loss			Fair Value
	Available-for-sale securities:
	Convertible debt securities	$	2,030	$	497			$	—			$	2,527			$	3,370		$	—	$	(196	)	$	3,174
	Redeemable preferred shares	4,599		311				—				4,910				—			—		—			—
	Total available-for-sale securities	$	6,629	$	808			$	—			$	7,437			$	3,370		$	—	$	(196	)	$	3,174
	Investments in E-Commerce and Life Media (F-Tuan)
	In June 2012, Life Media Limited ("F-tuan"), an entity with operations in China, acquired the Company's 49.8% interest in E-Commerce King Limited ("E-Commerce"), an entity with operations in China. In exchange for its interest in E-Commerce and an additional $25.0 million of cash consideration, the Company received a 19.1% interest in F-tuan in the form of common and Series E preferred shares. The Company recognized a non-operating gain of $56.0 million as a result of the transaction, which is included within "Other expense, net" on the consolidated statement of operations for the year ended December 31, 2012. The gain represented the excess of the fair value of the Company's investments in F-tuan over the carrying value of its E-Commerce investment as of the date of the transaction and the $25.0 million of cash consideration.
	In August 2013, the Company entered into an exchange transaction with F-tuan whereby it received newly issued shares of Series F preferred stock in exchange for all shares of F-tuan common stock previously held by the Company and $8.0 million of cash consideration, which was paid in two installments of $6.5 million and $1.5 million in August and October 2013, respectively. The transaction was recorded at cost. The Company’s investments in F-tuan following this transaction are in the form of Series E and Series F preferred shares. Those preferred shares rank pari passu with certain other classes of F-tuan’s outstanding preferred stock and have an aggregate liquidation preference of $85.5 million. The Company’s voting interest in F-tuan remained 19.1% after the transaction.
	The Company's investments in the Series E and Series F preferred shares of F-tuan are classified as available-for-sale securities because the investee's Memorandum of Association provides for redemption of the preferred shares at the Company's option beginning in October 2017. The Company's investment in the common shares of F-tuan, which were held prior to the August 2013 exchange transaction, was accounted for using the cost method of accounting because the Company did not have the ability to exercise significant influence over the operating and financial policies of the investee. As discussed below, the Company's investments in F-tuan were written down to zero through an other-than-temporary impairment charge as of December 31, 2013, and continue to have an estimated fair value of zero as of December 31, 2014.
	Other Investments
	In February 2014, the Company acquired redeemable preferred shares in an online home services company for $4.6 million. The shares are accounted for as available-for-sale securities.
	In February 2013, the Company purchased preferred shares in a non-U.S.-based payment processor for $13.6 million. The Company purchased $2.1 million of additional preferred shares from that entity in July 2014. This investment is accounted for using the cost method of accounting because the Company does not have the ability to exercise significant influence over the operating and financial policies of the investee.
	Other-Than-Temporary Impairment
	For the year ended December 31, 2014, the Company recorded $2.0 million of other-than-temporary impairments, including a $1.3 million impairment of an investment in convertible debt securities, which are reported within "Other expense, net" on the consolidated statements of operations.
	For the year ended December 31, 2013, the Company recorded an $85.5 million other-than-temporary impairment of its investments in F-tuan. F-tuan has operated at a loss since its inception and has used proceeds from equity offerings to fund investments in marketing and other initiatives to grow its business. As discussed above, the Company participated in an equity funding round in 2013 and the aggregate cash proceeds raised by F-tuan in that round, which were funded in two installments in September and October 2013 and included proceeds received from another investor, were intended to fund its operations for approximately six months, at which time additional financing would be required. In December 2013, the Company was notified by F-tuan's largest shareholder, which had served as a source of funding and operational support, that they had made a strategic decision to cease providing support to F-tuan. At its December 12, 2013 meeting, the Company's Board of Directors discussed the Company's strategy with respect to the Chinese market in light of this information. After that meeting, management pursued opportunities to divest its minority investment in F-tuan either for cash or in exchange for a minority equity investment in a larger competitor, but no agreement was ultimately reached. At its February 11, 2014 meeting, the Board of Directors determined that the Company should not provide funding to F-tuan in future periods. At that time, F-tuan required additional financing to continue its operations. Given the uncertainty as to whether it would be able to obtain such financing and the Company's decision not to provide significant funding itself, the Company concluded that there was substantial doubt as to F-tuan's ability to operate as a going concern for the foreseeable future.
	The Company's evaluation of other-than-temporary impairments involves consideration of qualitative and quantitative factors regarding the severity and duration of the unrealized loss, as well as the Company's intent and ability to hold the investment for a period of time that is sufficient to allow for an anticipated recovery in value. As a result of F-tuan's liquidity needs, the decision by existing shareholders to cease providing support, the Company's inability to find a buyer for its minority investment, the Company's decision not to be a source of significant funding itself and the expectation that any subsequent third party investment, if one occurs, would substantially dilute the existing shareholders, the Company concluded that its investment in F-tuan was other-than-temporarily impaired and its best estimate of fair value was zero. Accordingly, the Company recognized an $85.5 million impairment charge in earnings for the year ended December 31, 2013, bringing the fair value of the investment to zero. The Company's investments in F-tuan continue to have an estimated fair value of zero as of December 31, 2014.
	For the year ended December 31, 2012, the Company recorded a $50.6 million other-than-temporary impairment of its investments in F-tuan. As described above, the Company obtained these investments in June 2012 as part of a transaction in which it received a 19% interest in F-tuan, in the form of common and Series E preferred shares, in exchange for its 49.8% interest in E-Commerce and an additional $25.0 million of cash consideration. The $128.1 million acquisition-date fair value of the investments in F-tuan, a nonpublic entity, was determined using the discounted cash flow method, which is an income approach, and the resulting value was corroborated using the market approach. The inputs used to estimate fair value under the discounted cash flow method included financial projections and the discount rate. Because these fair value inputs are unobservable, fair value measurements of the investments in F-tuan are classified within Level 3 of the fair value hierarchy.
	In connection with the acquisition-date fair value measurements of the investments in F-tuan, the Company obtained financial projections from the investee. The Company evaluated those financial projections based on its knowledge of the business and related market conditions. As a result of that evaluation, downward adjustments were applied to reduce the anticipated growth that was reflected in the original projections. A 25% discount rate was applied to the adjusted cash flow projections, which included an entity-specific risk premium to account for the riskiness and uncertainty inherent in the business. Additionally, the Company corroborated the acquisition-date fair value measurement of F-tuan by estimating the fair value of its 49.8% interest in E-Commerce at the time of the transaction and comparing the estimated fair value of the consideration transferred, including the additional $25.0 million of cash consideration, to the estimated fair value of the investments in F-tuan that were received.
	In January 2013, the Company obtained updated financial projections from F-tuan, as well as their operating results for the year ended December 31, 2012. The investee's operating loss for the year-ended December 31, 2012 was lower than the loss that was forecasted in June 2012 at the time of the Company's investment, primarily due to lower-than-forecasted operating expenses. However, the investee's 2012 revenues were lower than the adjusted financial projections used at the time of the Company's investment and the updated financial projections provided by the investee at year-end indicated significant declines in forecasted revenues in future years, as compared to the adjusted financial projections used at the time of the Company's investment, due to reduced gross billings and deal margin forecasts. As of December 31, 2012, the Company continued to apply a discounted cash flow approach, corroborated by a market approach, to estimate the fair value of the investments in F-tuan. For the December 31, 2012 fair value measurements, the Company used the updated financial projections and a discount rate of 30%. The increase to the discount rate as compared to the acquisition-date fair value measurement was primarily attributable to an increase in the entity-specific risk premium to reflect the Company's assessment of the riskiness of this investment. The resulting fair value measurements of the investments in F-tuan totaled $77.5 million as of December 31, 2012, a $50.6 million reduction from the $128.1 million acquisition-date fair value measurement in June 2012.
	The Company's evaluation of other-than-temporary impairments involves consideration of qualitative and quantitative factors regarding the severity and duration of the unrealized loss, as well as the Company's intent and ability to hold the investment for a period of time that is sufficient to allow for an anticipated recovery in value. Although the Company's investments in F-tuan had not been in an unrealized loss position for an extended period of time as of December 31, 2012 and there were no plans to dispose of the investments at that time, the Company concluded that the impairment was other-than-temporary due to the significant declines in forecasted revenue growth and the severity of the unrealized loss.
	The $85.5 million and $50.6 million other-than-temporary impairments of its investments in F-tuan are reported within "Other expense, net" on the consolidated statements of operations for the years ended December 31, 2013 and 2012, respectively.
	The Company also recorded an additional $1.2 million other-than-temporary impairment of an equity method investment in a nonpublic entity, which is reported within "Other expense, net" on the consolidated statement of operations for the year ended December 31, 2012.

Supplemental_Consolidated_Bala

Supplemental Consolidated Balance Sheet and Statement of Operations Information	12 Months Ended
	Dec. 31, 2014
SUPPLEMENTAL CONSOLIDATED BALANCE SHEET AND STATEMENT OF OPERATIONS INFORMATION [Abstract]
Additional Financial Information Disclosures [Text Block]	SUPPLEMENTAL CONSOLIDATED BALANCE SHEETS AND STATEMENTS OF OPERATIONS INFORMATION
	The following table summarizes the Company's other expense, net for the years ended December 31, 2014, 2013 and 2012 (in thousands):
			Year Ended December 31,
			2014				2013				2012
	Interest income		$	1,564			$	1,721			$	2,522
	Interest expense		(907		)		(291		)		—
	Gain on E-Commerce transaction		—				—				56,032
	Impairments of investments		(2,036		)		(85,925		)		(50,553		)
	Loss on equity method investments		(459		)		(44		)		(9,925		)
	Foreign exchange (losses) gains, net		(31,526		)		(10,271		)		1,403
	Other		11				147				(3,238		)
	Other expense, net		$	(33,353	)		$	(94,663	)		$	(3,759	)
	The following table summarizes the Company's prepaid expenses and other current assets as of December 31, 2014 and 2013 (in thousands):
		December 31,
		2014				2013
	Current portion of unamortized tax effects on intercompany transactions	$	14,193			$	28,502
	Finished goods inventories	57,134				57,097
	Prepaid expenses	42,231				29,404
	Restricted cash	12,019				14,579
	Income taxes receivable	41,788				39,994
	VAT receivable	17,746				12,966
	Prepaid marketing	7,443				17,301
	Other	15,437				10,572
	Total prepaid expenses and other current assets	$	207,991			$	210,415
	The following table summarizes the Company's accrued merchant and supplier payables as of December 31, 2014 and 2013 (in thousands):
		December 31,
		2014				2013
	Accrued merchant payables	$	632,605			$	518,233
	Accrued supplier payables(1)	277,962				234,710
	Total accrued merchant and supplier payables	$	910,567			$	752,943
	-1	Amounts include payables to suppliers of inventories and providers of shipping and fulfillment services.
	The following table summarizes the Company's accrued expenses as of December 31, 2014 and 2013 (in thousands):
		December 31,
		2014				2013
	Marketing	$	15,962			$	12,001
	Refunds reserve	33,238				38,597
	Payroll and benefits	65,743				64,966
	Customer credits	44,463				44,728
	Professional fees	14,292				18,906
	Other	56,654				47,788
	Total accrued expenses	$	230,352			$	226,986
	The following table summarizes the Company's other current liabilities as of December 31, 2014 and 2013 (in thousands):
		December 31,
		2014				2013
	Income taxes payable	$	14,461			$	21,994
	VAT payable	33,436				37,627
	Sales taxes payable	9,042				10,412
	Deferred revenue	43,903				47,259
	Capital lease obligations	14,872				3,636
	Other	14,598				11,790
	Total other current liabilities	$	130,312			$	132,718
	The following table summarizes the Company's other non-current liabilities as of December 31, 2014 and 2013 (in thousands):
		December 31,
		2014				2013
	Long-term tax liabilities	$	82,138			$	109,286
	Deferred rent	13,200				9,148
	Capital lease obligations	23,387				5,665
	Other	17,559				7,598
	Total other non-current liabilities	$	136,284			$	131,697
	The following table summarizes the components of accumulated other comprehensive income, net of tax, as of December 31, 2014, 2013 and 2012 (in thousands):
		Foreign currency translation adjustments				Unrealized loss on available-for-sale securities				Pension liability adjustment				Total
	Balance as of December 31, 2012	$	12,393			$	53			$	—			$	12,446
	Other comprehensive income	12,559				(175		)		—				12,384
	Balance as of December 31, 2013	24,952				(122		)		—				24,830
Other comprehensive income (loss) before reclassification adjustments	11,812				(210		)		(1,500		)		10,102
Reclassification adjustment for impairment included in net loss	—				831				—				831
Other comprehensive income (loss)	11,812				621				(1,500		)		10,933
Balance as of December 31, 2014	$	36,764			$	499			$	(1,500	)		$	35,763
The effects of amounts reclassified from accumulated other comprehensive income to net loss for the years ended December 31, 2014, 2013 and 2012 are presented within the following line items in the consolidated statements of operations (in thousands):
		Year Ended December 31,												Consolidated Statements of Operations Line Item
		2014				2013				2012
Other-than-temporary impairment of available-for-sale security		$	1,340			$	—			$	—			Other expense, net
Less: Tax effect		(509		)		—				—				Provision for income taxes
Reclassification adjustment		$	831			$	—			$	—

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies Disclosure [Text Block]	COMMITMENTS AND CONTINGENCIES
	Leases
	The Company has entered into various non-cancelable lease agreements, primarily operating leases covering its offices throughout the world, with remaining lease periods expiring between 2015 and 2024. Rent expense under operating leases was $55.0 million, $42.3 million and $43.1 million for the years ended December 31, 2014, 2013 and 2012, respectively.
	The Company has lease arrangements for its headquarters located in Chicago, Illinois ("600 West Leases"), which account for 14% of its estimated future payments under operating leases as of December 31, 2014. The 600 West Leases are accounted for as operating leases with rent expense being recognized on a straight-line basis over the term of the lease, taking into account rent escalations and lease incentives. Rent escalations are annual and do not exceed 9% per year with a majority of the increases being approximately 2% per year. The initial durations of the 600 West Leases range from five to seven years, with renewal and expansion options ranging from one to five years. The amortization period of leasehold improvements related to the 600 West Leases is five years.
	The Company is responsible for paying its proportionate share of specified operating expenses and real estate taxes under certain of its lease agreements. These operating expenses are not included in the table below.
	Certain of the Company's computer equipment has been acquired under capital lease agreements, and estimated future payments under these capital lease agreements is included in the table below. As of December 31, 2014, the estimated future payments under operating leases and capital leases for each of the next five years and thereafter is as follows (in thousands):
		Capital Leases			Operating leases
	2015	$	14,936		$	53,776
	2016	14,136			49,094
	2017	9,424			38,628
	2018	697			27,659
	2019	522			11,455
	Thereafter	—			21,514
	Total minimum lease payments	39,715			$	202,126
	Less: Amount representing interest	(1,456		)
	Present value of net minimum capital lease payments	38,259
	Less: Current portion of capital lease obligations	(14,872		)
	Total long-term capital lease obligations	$	23,387
	Purchase Obligations
	The Company has entered into non-cancelable arrangements with third-parties, primarily related to information technology products and services. As of December 31, 2014, future payments under these contractual obligations were as follows (in thousands):
	2015	$	33,636
	2016	21,922
	2017	5,730
	2018	8
	2019	4
	Thereafter	—
	Total purchase obligations	$	61,300
	Legal Matters and Other Contingencies
	From time to time, the Company is party to various legal proceedings incident to the operation of its business. For example, the Company is currently involved in proceedings by stockholders, former employees and merchants, intellectual property infringement suits and suits by customers (individually or as class actions) alleging, among other things, violation of the Credit Card Accountability, Responsibility and Disclosure Act and state laws governing gift cards, stored value cards and coupons. Additionally, the Company is subject to general customer complaints seeking monetary damages, particularly in its Rest of World segment. The following is a brief description of significant legal proceedings.
	On February 8, 2012, the Company issued a press release announcing its expected financial results for the fourth quarter of 2011.  After finalizing its year-end financial statements, the Company announced on March 30, 2012 revised financial results, as well as a material weakness in its internal control over financial reporting related to deficiencies in its financial statement close process.  The revisions resulted in a reduction to fourth quarter 2011 revenue of $14.3 million. The revisions also resulted in an increase to fourth quarter operating expenses that reduced operating income by $30.0 million, net income by $22.6 million and earnings per share by $0.04.  Following this announcement, the Company and several of its current and former directors and officers were named as parties to the following outstanding securities and stockholder derivative lawsuits all arising out of the same alleged events and facts.
	The Company is currently a defendant in a proceeding pursuant to which, on October 29, 2012, a consolidated amended class action complaint was filed against the Company, certain of its directors and officers, and the underwriters that participated in the initial public offering of the Company's Class A common stock.  Originally filed in April 2012, the case is currently pending before the United States District Court for the Northern District of Illinois: In re Groupon, Inc. Securities Litigation. The complaint asserts claims pursuant to Sections 11 and 15 of the Securities Act of 1933 and Sections 10(b) and 20(a) of the Securities Exchange Act of 1934.  Allegations in the consolidated amended complaint include that the Company and its officers and directors made untrue statements or omissions of material fact by issuing inaccurate financial statements for the fiscal quarter and the fiscal year ending December 31, 2011 and by failing to disclose information about the Company's financial controls in the registration statement and prospectus for the Company's initial public offering of Class A common stock and in the Company's subsequently-issued earnings release dated February 8, 2012.  The class action lawsuit seeks an unspecified amount of monetary damages, reimbursement for fees and costs incurred in connection with the actions, including attorneys' fees, and various other forms of monetary and non-monetary relief.  On September 23, 2014, the court entered an order granting plaintiff's motion for class certification. The Company has filed a petition for leave to appeal that order in the United States Court of Appeals for the Seventh Circuit. The Seventh Circuit is holding that motion in order to allow the district court to first have the opportunity to address defendants' motion to exclude the opinions and testimony of the plaintiff's proposed market efficiency expert. On December 19, 2014, defendants filed their opening brief with respect to this motion.  On January 8, 2015, the plaintiff filed a response brief, to which the defendants filed a reply brief on January 20, 2015.
	In addition, federal and state purported stockholder derivative lawsuits have been filed against certain of the Company's current and former directors and officers.  The federal purported stockholder derivative lawsuit was originally filed in April 2012 and a consolidated stockholder derivative complaint, filed on July 30, 2012, is currently pending in the United States District Court for the Northern District of Illinois: In re Groupon Derivative Litigation.  Plaintiffs assert claims for breach of fiduciary duty and abuse of control.  The state derivative cases are currently pending before the Chancery Division of the Circuit Court of Cook County, Illinois: Orrego v. Lefkofsky, et al., was filed on April 5, 2012; and Kim v. Lefkofsky, et al., was filed on May 25, 2012. The state derivative complaints generally allege that the defendants breached their fiduciary duties by purportedly mismanaging the Company's business by, among other things, failing to utilize proper accounting controls and, in the case of one of the state derivative lawsuits, by engaging in alleged insider trading of the Company's Class A common stock and misappropriating information.  In addition, one state derivative case asserts a claim for unjust enrichment.  The derivative lawsuits purport to seek to recoup for the Company an unspecified amount of monetary damages allegedly sustained by the Company, restitution from defendants, reimbursement for fees and costs incurred in connection with the actions, including attorneys' fees, and various other forms of monetary and non-monetary relief.  On June 20, 2012, the Company and the individual defendants filed a motion requesting that the court stay the consolidated federal derivative action pending resolution of the consolidated federal class actions.  On July 31, 2012, the court granted defendants' motion in part, and stayed the consolidated federal derivative action pending a separate resolution of upcoming motions to dismiss in the consolidated federal class actions.  On June 15, 2012, the state plaintiffs filed a motion to consolidate the state derivative actions, which was granted on July 2, 2012, and on July 5, 2012, the plaintiffs filed a motion for appointment of co-lead plaintiffs and co-lead counsel, which was granted on July 27, 2012.  No consolidated complaint has been filed in the state derivative action. On September 14, 2012, the court granted a motion filed by the parties requesting that the court stay the state derivative actions pending the federal court's resolution of anticipated motions to dismiss in the consolidated federal class action.  On April 18, 2013, the state court appointed a lead plaintiff and approved its selection of lead counsel and local counsel for the purported class. Following entry of the court's order denying defendants' motions to dismiss in In re Groupon Securities Litigation, the courts in both the state and federal derivative actions granted motions requesting that the respective courts extend the litigation stays currently in place pending further developments in In re Groupon, Inc. Securities Litigation.
	The Company intends to defend all of the securities and stockholder derivative lawsuits vigorously.
	In 2010, the Company was named as a defendant in a series of class actions that came to be consolidated into a single case in the U.S. District Court for the Southern District of California.  The consolidated case is referred to as In re Groupon Marketing and Sales Practices Litigation. The Company denies liability, but the parties agreed to settle the litigation for $8.5 million before any determination had been made on the merits or with respect to class certification.  Because the case had been filed as a class action, the parties were required to provide proper notice and obtain court approval for the settlement. During that process, certain individuals asserted various objections to the settlement.  The parties to the case opposed the objections and on December 14, 2012, the district court approved the settlement over the various objections.
	Subsequent to the entry of the order approving settlement, certain of the objectors filed a notice of appeal, contesting the settlement and appealing the matter to the United States Court of Appeals for the Ninth Circuit, where the case remains pending.  The Company believes that the settlement is valid and intends to oppose the appeal.  Plaintiffs also maintain that the settlement is valid and will be opposing the appeal.  The settlement, however, is not effective during the pendency of the appeal.  The Company does not know when the appeal will be resolved.  Depending on the outcome of the appeal, it is possible that the settlement will be rejected, or that there will be further proceedings in the appellate court or district court, or that the settlement will be enforced at that time without further objections or proceedings.
	In addition, third parties have from time to time claimed, and others may claim in the future, that the Company has infringed their intellectual property rights. The Company is subject to intellectual property disputes, and expects that it will increasingly be subject to intellectual property infringement claims as its services expand in scope and complexity. The Company has in the past litigated such claims, and several of these claims are currently pending. The Company may also become more vulnerable to third party claims as laws such as the Digital Millennium Copyright Act are interpreted by the courts, and as the Company becomes subject to laws in jurisdictions where the underlying laws with respect to the potential liability of online intermediaries are either unclear or less favorable. The Company believes that additional lawsuits alleging that it has violated patent, copyright or trademark laws will be filed against it. Intellectual property claims, whether meritorious or not, are time consuming and costly to resolve, could require expensive changes in the Company's methods of doing business, or could require it to enter into costly royalty or licensing agreements.
	The Company is also subject to, or in the future may become subject to, a variety of regulatory inquiries across the jurisdictions where the Company conducts its business, including, for example, consumer protection, marketing practices, tax and privacy rules and regulations. Any regulatory actions against the Company, whether meritorious or not, could be time consuming, result in costly litigation, damage awards, injunctive relief or increased costs of doing business through adverse judgment or settlement, require the Company to change its business practices in expensive ways, require significant amounts of management time, result in the diversion of significant operational resources or otherwise harm the Company's business.
	During the fourth quarter of 2014, two foreign tax authorities issued assessments totaling $46.5 million to subsidiaries of the Company for additional value-added taxes (VAT) covering periods ranging from January 2011 to May 2014, including interest and penalties through the date of the assessments. Those tax authorities are alleging that, for VAT purposes, the Company's revenues from voucher sales should reflect the total amounts collected from purchasers of those vouchers, rather than the amounts that the Company retains after deducting the portion that is payable to the featured merchants. The Company believes that the assessments are without merit and intends to vigorously defend itself in these matters.
	The Company establishes an accrued liability for loss contingencies related to legal and regulatory matters when the loss is both probable and estimable. These accruals represent management's best estimate of probable losses and in such cases, there may be an exposure to loss in excess of the amounts accrued. For each matter described above, there is inherent and significant uncertainties based on, among other factors, the stage of the proceedings, developments in the applicable facts of law, or the lack of a specific damage claim. In addition, for some matters for which a loss is probable or reasonably possible, an estimate of the amount of loss or range of loss is not possible, and we may be unable to estimate the possible loss or range of losses that could potentially result from the application of non-monetary remedies. Currently, the Company is unable to reasonably estimate the amount of reasonably possible losses in excess of the amounts accrued for the securities and stockholder derivative lawsuits. For the remaining matters described above, the Company believes that the amount of reasonably possible losses in excess of the amounts accrued would not have a material adverse effect on its business, consolidated financial position, results of operations or cash flows. The Company's accrued liabilities for loss contingencies related to legal and regulatory matters may change in the future as a result of new developments, including, but not limited to, the occurrence of new legal matters, changes in the law or regulatory environment, adverse or favorable rulings, newly discovered facts relevant to the matter, or changes in the strategy for the matter. Regardless of the outcome, litigation can have an adverse impact on the Company because of defense and settlement costs, diversion of management resources and other factors.
	Indemnifications
	In the normal course of business to facilitate transactions related to its operations, the Company indemnifies certain parties, including employees, lessors, service providers and merchants, with respect to various matters. The Company has agreed to hold certain parties harmless against losses arising from a breach of representations or covenants, or other claims made against those parties. These agreements may limit the time within which an indemnification claim can be made and the amount of the claim. The Company is also subject to increased exposure to various claims as a result of its acquisitions, particularly in cases where the Company is entering into new businesses in connection with such acquisitions. The Company may also become more vulnerable to claims as it expands the range and scope of its services and is subject to laws in jurisdictions where the underlying laws with respect to potential liability are either unclear or less favorable. In addition, the Company has entered into indemnification agreements with its officers and directors, and the Company's bylaws contain similar indemnification obligations to agents.
	It is not possible to determine the maximum potential amount under these indemnification agreements due to the limited history of prior indemnification claims and the unique facts and circumstances involved in each particular agreement. Historically, any payments that the Company has made under these agreements have not had a material impact on the operating results, financial position or cash flows of the Company.

Revolving_Credit_Agreement_Not

Revolving Credit Agreement (Notes)	12 Months Ended
	Dec. 31, 2014
Line of Credit Facility [Line Items]
Debt Disclosure [Text Block]	REVOLVING CREDIT AGREEMENT
	In August 2014, the Company entered into a three-year senior secured revolving credit agreement (the "Credit Agreement") that provides for aggregate principal borrowings of up to $250.0 million. Borrowings under the Credit Agreement bear interest, at the Company's option, at a rate per annum equal to the Alternate Base Rate or Adjusted LIBO Rate (each as defined in the Credit Agreement) plus an additional margin ranging between 0.25% and 2.00%. The Company is required to pay quarterly commitment fees ranging from 0.20% to 0.35% per annum of the average daily amount available under the Credit Agreement. The Credit Agreement also provides for the issuance of up to $45.0 million in letters of credit, provided that the sum of outstanding borrowings and letters of credit do not exceed the maximum funding commitment of $250.0 million.
	The Credit Agreement is secured by substantially all of the Company's and its subsidiaries' tangible and intangible assets, including a pledge of 100% of the outstanding capital stock of substantially all of its direct and indirect domestic subsidiaries and 65% of the shares or equity interests of first-tier foreign subsidiaries and each U.S. entity whose assets substantially consist of capital stock and/or intercompany debt of one or more foreign subsidiaries, subject to certain exceptions. Certain of the Company's domestic subsidiaries are guarantors under the Credit Agreement.
	The Credit Agreement contains various customary restrictive covenants that limit the Company's ability to, among other things: incur additional indebtedness; enter into sale or leaseback transactions; make investments, loans or advances; grant or incur liens on assets; sell assets; engage in mergers, consolidations, liquidations or dissolutions; engage in transactions with affiliates; and make dividend payments. The Credit Agreement requires the Company to maintain compliance with specified financial covenants, comprised of a minimum fixed charge coverage ratio, a maximum leverage ratio, and a minimum liquidity ratio, each as set forth in the Credit Agreement. The Company is also required to maintain, as of the last day of each fiscal quarter, unrestricted cash of at least $400.0 million, including $200.0 million in accounts held with lenders under the Credit Agreement or their affiliates. Non-compliance with these covenants may result in termination of the commitments under the Credit Agreement and any then outstanding borrowings may be declared due and payable immediately. The Company has the right to terminate the Credit Agreement or reduce the available commitments at any time.
	As of December 31, 2014, the Company had no borrowings or letters of credit outstanding under the Credit Agreement and was in compliance with all covenants.

Stockholders_Equity_Stockholde

Stockholders' Equity Stockholders' Equity and Stock-Based Compensation (Note)	12 Months Ended
	Dec. 31, 2014
Stockholders' Equity Note [Abstract]
Stockholders' Equity and Stock-Based Compensation Note [Text Block]	STOCKHOLDERS' EQUITY
	Preferred Stock
	The Company's Board of Directors ("the Board") has the authority, without approval by the stockholders, to issue up to a total of 50,000,000 shares of preferred stock in one or more series. The Board may establish the number of shares to be included in each such series and may fix the designations, preferences, powers and other rights of the shares of a series of preferred stock. The Board could authorize the issuance of preferred stock with voting or conversion rights that could dilute the voting power or rights of the holders of the Class A common stock or Class B common stock. As of December 31, 2014 and 2013, there were no shares of preferred stock outstanding.
	Common Stock
	The Company's certificate of incorporation, as amended and restated, authorizes three classes of common stock: Class A common stock, Class B common stock and common stock. No shares of common stock will be issued or outstanding until October 31, 2016, at which time all outstanding shares of Class A common stock and Class B common stock will automatically convert into shares of common stock. In addition, the Company's certificate of incorporation authorizes shares of undesignated preferred stock, the rights, preferences and privileges of which may be designated from time to time by the Board.
	Holders of Class A common stock and Class B common stock have identical rights, except that holders of Class A common stock are entitled to one vote per share and holders of Class B common stock are entitled to 150 votes per share. Holders of shares of Class A common stock and Class B common stock will vote together as a single class on all matters (including the election of directors) submitted to a vote of stockholders, except that there will be separate votes of holders of shares of the Class A common stock and Class B common stock in the following circumstances:
	•	if the Company proposes to amend its certificate of incorporation to alter or change the powers, preferences or special rights of the shares of a class of its stock so as to affect them adversely or to increase or decrease the par value of the shares of a class of the Company's stock;
	•	if the Company proposes to treat the shares of a class of its stock differently with respect to any dividend or distribution of cash, property or shares of the Company's stock paid or distributed by the Company;
	•	if the Company proposes to treat the shares of a class of its stock differently with respect to any subdivision or combination of the shares of a class of the Company's stock; or
	•	if the Company proposes to treat the shares of a class of its stock differently in connection with a change in control, liquidation, dissolution, distribution of assets or winding down of the Company with respect to any consideration into which the shares are converted or any consideration paid or otherwise distributed to its stockholders.
	The Company may not increase or decrease the authorized number of shares of Class A common stock or Class B common stock without the affirmative vote of the holders of a majority of the combined voting power of the outstanding shares of Class A common stock and Class B common stock, voting together as a single class. In addition, the Company may not issue any shares of Class B common stock, other than in connection with stock dividends, stock splits and similar transactions, unless that issuance is approved by the affirmative vote of the holders of a majority of the outstanding shares of Class B common stock. There is no cumulative voting for the election of directors.
	Except as otherwise expressly provided in the Company's certificate of incorporation or as required by applicable law, shares of Class A common stock and Class B common stock will have the same rights and privileges and rank equally, share ratably and be identical in all respects as to all matters, including, without limitation, those described below.
	Subject to preferences that may apply to any shares of preferred stock outstanding at the time, the holders of Class A common stock and Class B common stock shall be entitled to share equally, ratably and identically, on a per share basis, with respect to any dividends that the Board may determine to issue from time to time, unless different treatment of the shares of such class is approved by the affirmative vote of the holders of the majority of the outstanding shares of Class A common stock and Class B common stock, each voting separately as a class. In the event a dividend is paid in the form of shares of common stock or rights to acquire shares of common stock, the holders of Class A common stock will receive shares of Class A common stock, or rights to acquire shares of Class A common stock, as the case may be, and the holders of Class B common stock will receive shares of Class B common stock, or rights to acquire shares of Class B common stock, as the case may be.
	Upon liquidation, dissolution or winding-up of the Company, the holders of Class A common stock and Class B common stock will be entitled to share equally, ratably and identically in all assets remaining after the payment of any liabilities and the liquidation preferences on any outstanding preferred stock, unless different treatment of the shares of such class is approved by the affirmative vote of the holders of the majority of the outstanding shares of Class A common stock and Class B common stock, each voting separately as a class.
	Upon (i) the closing of the sale, transfer or other disposition of all or substantially all of our assets, (ii) the consummation of a merger, consolidation, business combination or other similar transaction which results in our voting securities outstanding immediately prior to the transaction (or the voting securities issued with respect to our voting securities outstanding immediately prior to the transaction) representing less than a majority of the combined voting power and outstanding capital stock of the voting securities of the Company or the surviving or acquiring entity, (iii) the recapitalization, liquidation, dissolution or other similar transaction which results in the voting securities outstanding immediately prior to the transaction representing less than a majority of the combined voting power and outstanding capital stock of the Company or the surviving entity or parent entity or (iv) an issuance by the Company, in one transaction or a series of related transactions, of voting securities representing more than 2% of the total voting power of the Company (assuming the Class A common stock and Class B common stock each have one vote per share) to any person or group of affiliated persons who prior to such issuance held less than a majority of the total voting power of the Company (assuming the Class A common stock and Class B common stock each have one vote per share) and who subsequent to the issuance would hold a majority of the total voting power, the holders of Class A common stock and Class B common stock will be treated equally and identically with respect to shares of Class A common stock or Class B common stock owned by them, unless different treatment of the shares of each class is approved by the affirmative vote of the holders of a majority of the outstanding shares of Class A common stock and Class B common stock, each voting separately as a class.
	If the Company subdivides or combines in any manner outstanding shares of Class A common stock or Class B common stock, the outstanding shares of the other class will be subdivided or combined in the same manner, unless different treatment of the shares of each class is approved by the affirmative vote of the holders of a majority of the outstanding shares of Class A common stock and Class B common stock, each voting separately as a class.
	Share Repurchase Program
	The Board has authorized the Company to purchase up to $300.0 million of its outstanding Class A common stock through August 2015. The timing and amount of any share repurchases is determined based on market conditions, share price and other factors, and the program may be discontinued or suspended at any time. During the years ended December 31, 2014 and 2013, the Company purchased 22,806,304 and 4,432,800 shares of Class A common stock, respectively, for an aggregate purchase price of $151.9 million and $46.6 million (including fees and commissions), respectively, under the share repurchase program. As of December 31, 2014, up to $101.5 million of Class A common stock remains available for repurchase under the share repurchase program.

Compensation_Arrangements_Note

Compensation Arrangements (Notes)	12 Months Ended
	Dec. 31, 2014
Compensation Arrangements [Abstract]
Disclosure of Compensation Related Costs, Share-based Payments [Text Block]	COMPENSATION ARRANGEMENTS
	Groupon, Inc. Stock Plans
	In January 2008, the Company adopted the ThePoint.com 2008 Stock Option Plan, as amended (the "2008 Plan"), under which options for up to 64,618,500 shares of common stock were authorized to be issued to employees, consultants and directors of ThePoint.com, which is now the Company. In April 2010, the Company established the Groupon, Inc. 2010 Stock Plan, as amended in April 2011 (the "2010 Plan"), under which options and restricted stock units ("RSUs") for up to 20,000,000 shares of common stock were authorized for future issuance to employees, consultants and directors of the Company. In August 2011, the Company established the Groupon, Inc. 2011 Stock Plan (the "2011 Plan"), under which options, RSUs and performance stock units for up to 50,000,000 shares of common stock were authorized for future issuance to employees, consultants and directors of the Company.
	The Groupon, Inc. Stock Plans (the "Plans") are administered by the Compensation Committee of the Board, which determines the number of awards to be issued, the corresponding vesting schedule and the exercise price for options. As of December 31, 2014, 44,043,631 shares were available for future issuance under the Plans. Prior to January 2008, the Company issued stock options and RSUs that are governed by employment agreements, some of which are still outstanding.
	The Company recognized stock-based compensation expense of $122.0 million, $121.5 million and $104.1 million for the years ended December 31, 2014, 2013 and 2012, respectively, related to stock awards issued under the Plans, acquisition-related awards and subsidiary awards. The Company also capitalized $11.2 million, $9.1 million and $9.7 million of stock-based compensation for the years ended December 31, 2014, 2013 and 2012, respectively, in connection with internally-developed software.
	As of December 31, 2014, a total of $221.7 million of unrecognized compensation costs related to unvested stock awards and unvested acquisition-related awards are expected to be recognized over a remaining weighted-average period of 1.30 years.
	Employee Stock Purchase Plan
	The Company is authorized to grant up to 10,000,000 shares of common stock under its employee stock purchase plan ("ESPP"). For the years ended December 31, 2014 and 2013, 857,171 and 774,288 shares of common stock were issued under the ESPP, respectively. No shares of common stock were issued under the ESPP for the year ended December 31, 2012.
	Stock Options
	The exercise price of stock options granted is equal to the fair value of the underlying stock on the date of grant. The contractual term for stock options expires ten years from the grant date. Stock options generally vest over a three or four-year period, with 25% of the awards vesting after one year and the remainder of the awards vesting on a monthly or quarterly basis thereafter. The fair value of stock options on the date of grant is amortized on a straight-line basis over the requisite service period.
	The table below summarizes the stock option activity for the year ended December 31, 2014:
			Options		Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value
								(in thousands) (1)
	Outstanding at December 31, 2013		3,355,054		$	1.11	6.04	$	35,742
	Exercised		(1,029,471	)	$	1.09
	Forfeited		(62,589	)	$	2.41
	Outstanding at December 31, 2014		2,262,994		$	1.09	5.03	$	16,226
	Exercisable at December 31, 2014		2,262,994		$	1.09	5.03	$	16,226
	-1	The aggregate intrinsic value of options outstanding and exercisable represents the total pretax intrinsic value (the difference between the fair value of the Company's stock on the last day of each period and the exercise price, multiplied by the number of options where the fair value exceeds the exercise price) that would have been received by the option holders had all option holders exercised their options as of December 31, 2014 and 2013, respectively.
	The fair value of stock options granted was estimated on the date of grant using the Black-Scholes-Merton option-pricing model. Expected volatility was based on historical volatilities for publicly-traded options of comparable companies over the estimated expected life of the stock options. The expected term represents the period of time the stock options are expected to be outstanding and was based on the "simplified method." The Company used the "simplified method" due to the lack of sufficient historical exercise data to provide a reasonable basis upon which to otherwise estimate the expected life of the stock options. The risk-free interest rate was based on yields on U.S. Treasury STRIPS with a maturity similar to the estimated expected life of the stock options.
	The Company did not grant any stock options during the years ended December 31, 2014, 2013 and 2012. The total intrinsic value of options that were exercised during the years ended December 31, 2014, 2013 and 2012 was $6.5 million, $30.0 million and $75.2 million, respectively.
	Restricted Stock Units
	The restricted stock units granted under the Plans generally vest over a four-year period, with 25% of the awards vesting after one year and the remaining awards vesting on a monthly or quarterly basis thereafter. Restricted stock units are generally amortized on a straight-line basis over the requisite service period, except for restricted stock units with performance conditions, which are amortized using the accelerated method.
	The table below summarizes activity regarding unvested restricted stock units under the Plans for the year ended December 31, 2014:
			Restricted Stock Units		Weighted- Average Grant Date Fair Value (per share)
	Unvested at December 31, 2013		41,648,055		$	8.06
	Granted		29,568,490		$	7.59
	Vested		(17,323,096	)	$	8.07
	Forfeited		(12,555,522	)	$	7.96
	Unvested at December 31, 2014		41,337,927		$	7.78
	The weighted-average grant date fair value of restricted stock units granted in 2013 and 2012 was $7.23 and $8.99, respectively. The fair value of restricted stock units that vested during each of the three years ended December 31, 2014, 2013 and 2012 was $139.8 million, $126.5 million and $50.2 million, respectively.
	Performance Share Units
	The Company completed its acquisition of Ticket Monster on January 2, 2014, as described in Note 3 "Business Combinations and Acquisitions of Noncontrolling Interests," and approximately 2,000,000 performance share units were granted to certain key employees of that subsidiary. The vesting of these awards into shares of the Company's Class A common stock is contingent upon the subsidiary's achievement of specified financial targets over three annual performance periods for the years ending December 31, 2014, 2015 and 2016 and is subject to continued employment at the end of each performance period. If the financial targets for a performance period are not achieved, no shares will be issued for that performance period. The grant date fair value of the performance share units was $8.07 per share. For the performance period ending December 31, 2014, 0.8 million performance share units were forfeited because the performance conditions were not met.
	The table below summarizes activity regarding unvested performance share units for the year ended December 31, 2014:
			Performance Share Units		Weighted- Average Grant Date Fair Value (per share)
	Unvested at December 31, 2013		—		$	—
	Granted		1,983,232		$	8.07
	Vested		—		$	—
	Forfeited		(967,388	)	$	8.07
	Unvested at December 31, 2014		1,015,844		$	8.07
	Restricted Stock Awards
	The Company has granted restricted stock awards in connection with business combinations. Compensation expense on these awards is recognized on a straight-line basis over the requisite service periods.
	The table below summarizes activity regarding unvested restricted stock for the year ended December 31, 2014:
			Restricted Stock Awards		Weighted- Average Grant Date Fair Value (per share)
	Unvested at December 31, 2013		97,677		$	14
	Granted		—		$	—
	Vested		(50,481	)	$	14.54
	Forfeited		(13,129	)	$	17.07
	Unvested at December 31, 2014		34,067		$	15.53
	The fair value of restricted stock that vested during the years ended December 31, 2014, 2013 and 2012 was $0.7 million, $4.1 million and $10.2 million, respectively.
	Subsidiary Awards
	The Company made several acquisitions during the years ended December 31, 2011 and 2010 in which the selling shareholders of the acquired companies were granted RSUs and stock options in the Company's subsidiaries ("subsidiary awards"). These subsidiary awards were issued in conjunction with the acquisitions as a way to retain and motivate key employees. They generally vested on a quarterly basis for a period of three or four years, and were potentially dilutive to the Company's ownership percentage of the corresponding subsidiaries. A significant portion of the subsidiary awards were classified as liabilities on the consolidated balance sheets due to the existence of put rights that allowed the selling shareholders to put their stock back to the Company. The liabilities for the subsidiary awards were remeasured on a quarterly basis, with the offset to stock-based compensation expense within "Selling, general and administrative" on the consolidated statements of operations. The Company modified its liability-classified subsidiary awards in 2012 by paying $17.0 million in cash and issuing 660,539 shares of the Company's common stock to settle the vested portion and providing for future settlement of the unvested portion in cash or shares of the Company's common stock upon completion of the requisite service period. See Purchases of Additional Interests in Consolidated Subsidiaries in Note 3 "Business Combinations and Acquisitions of Noncontrolling Interests."
	Swiss Pension Plan
	The Company maintains a pension plan covering employees in Switzerland pursuant to the requirements of Swiss pension law. Contributions to the Swiss pension plan are paid by the employees and the employer. Certain features of the plan require it to be categorized as a defined benefit plan under U.S. GAAP. These features include a minimum interest guarantee on retirement savings accounts, a pre-determined factor for converting accumulated savings account balances into a pension, and death and disability benefits. The projected benefit obligation and net unfunded pension liability were $4.9 million and $2.0 million, respectively, as of December 31, 2014 and the net periodic pension cost was $0.6 million for the year then ended.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Tax Disclosure [Text Block]	INCOME TAXES
	The components of pretax (loss) income for the years ended December 31, 2014, 2013 and 2012 were as follows (in thousands):
		Year Ended December 31,
		2014				2013				2012
	United States	$	(20,057	)		$	62,021			$	88,638
	International	(28,138		)		(80,930		)		6,304
	(Loss) income before provision for income taxes	$	(48,195	)		$	(18,909	)		$	94,942
	The provision for income taxes for the years ended December 31, 2014, 2013 and 2012 consisted of the following components (in thousands):
		Year Ended December 31,
		2014				2013				2012
	Current taxes:
	U.S. federal	$	(3,518	)		$	22,321			$	41,551
	State	69				1,693				4,778
	International	30,279				64,078				107,295
	Total current taxes	26,830				88,092				153,624
	Deferred taxes:
	U.S. federal	(5,132		)		4,675				(2,977		)
	State	(742		)		(5,687		)		(236		)
	International	(5,232		)		(17,043		)		(4,438		)
	Total deferred taxes	(11,106		)		(18,055		)		(7,651		)
	Provision for income taxes	$	15,724			$	70,037			$	145,973
	The items accounting for differences between the income tax provision or benefit computed at the federal statutory rate and the provision for income taxes for the years ended December 31, 2014, 2013 and 2012 were as follows:
		Year Ended December 31,
		2014				2013				2012
	U.S. federal income tax (benefit) provision at statutory rate	$	(16,868	)		$	(6,618	)		$	33,230
	Foreign income and losses taxed at different rates	4,815				14,299				10,565
	Unrecognized tax benefits on E-Commerce transaction	—				—				17,404
	State income taxes, net of federal benefits and state tax credits	(10,051		)		(5,361		)		3,965
	Change in valuation allowances	23,515				24,404				29,249
	Effect of foreign and state rate changes on deferred items	178				837				(487		)
	Tax effects of intercompany transactions(1)	13,098				35,158				31,011
	Non-deductible stock-based compensation expense	6,503				9,000				14,641
	Federal research and development credits	(4,693		)		(4,650		)		—
	Non-deductible or non-taxable items	(773		)		2,968				6,395
	Provision for income taxes	$	15,724			$	70,037			$	145,973
	-1	Includes a tax benefit of $24.4 million for the year ended December 31, 2014 resulting from decreases in the Company's liabilities for uncertain tax positions.
	The deferred income tax assets and liabilities consisted of the following components as of December 31, 2014 and 2013 (in thousands):
		December 31,
		2014				2013
	Deferred tax assets:
	Reserves and allowances	$	32,379			$	65,356
	Stock-based compensation	6,911				13,462
	Net operating loss and tax credit carryforwards	221,674				152,271
	Intangible assets, net	11,910				30,039
	Investments	1,441				3,730
	Unrealized foreign exchange losses	5,011				—
	Other	2,610				1,692
	Total deferred tax assets	281,936				266,550
	Less valuation allowances	(205,486		)		(173,577		)
	Deferred tax assets, net of valuation allowance	76,450				92,973
	Deferred tax liabilities:
	Unrealized foreign exchange gains	—				(3,034		)
	Prepaid expenses and other assets	(1,455		)		(1,078		)
	Property, equipment and software, net	(25,159		)		(19,239		)
	Deferred revenue	(25,013		)		(64,154		)
	Total deferred tax liabilities	(51,627		)		(87,505		)
	Net deferred tax asset	$	24,823			$	5,468
	The Company regularly reviews deferred tax assets to assess whether it is more likely than not that the deferred tax assets will be realized and, if necessary, establishes a valuation allowance for portions of such assets to reduce the carrying value. For purposes of assessing whether it is more likely than not that the Company's deferred tax assets will be realized, the Company considers the following four sources of taxable income for each tax jurisdiction: (a) future reversals of existing taxable temporary differences, (b) projected future earnings, (c) taxable income in carryback years, to the extent that carrybacks are permitted under the tax laws of the applicable jurisdiction, and (d) tax planning strategies, which represent prudent and feasible actions that a company ordinarily might not take, but would take to prevent an operating loss or tax credit carryforward from expiring unused. The Company has incurred significant losses in recent years and had accumulated deficits of $922.0 million and $848.9 million as of December 31, 2014 and 2013, respectively. A cumulative loss in the most recent three-year period is a significant piece of negative evidence that is difficult to overcome when assessing the realizability of deferred tax assets. The Company has only recognized deferred tax assets to the extent that they will be realizable either through future reversals of existing taxable temporary differences, through taxable income in carryback years for the applicable jurisdictions or based on projections of future income for those jurisdictions in a cumulative income position for the most recent three-year period. During the fourth quarter of 2013, earnings in the United States moved to a cumulative income position for the most recent three-year period and the Company released a portion of the valuation allowance against its federal and state deferred tax assets, resulting in a $9.6 million reduction to income tax expense. The Company continues to maintain a valuation allowance in the United States against a portion of its acquired domestic federal net operating losses that are subject to limitations under the tax law and state net operating loss carryforwards and tax credits that are not expected to be realized. As of December 31, 2014 and 2013, the Company recorded a valuation allowance of $205.5 million and $173.6 million, respectively, against its domestic and foreign net deferred tax assets, as it believes it is more likely than not that these benefits will not be realized.
	The Company had $121.2 million of federal and $270.5 million of state net operating loss carryforwards as of December 31, 2014 which will begin expiring in 2027 and 2016, respectively. As of December 31, 2014, the Company had $714.9 million of foreign net operating loss carryforwards, a significant portion of which carry forward for an indefinite period.
	The Company is subject to taxation in the United States, state jurisdictions and foreign jurisdictions. Significant judgment is required in determining the worldwide provision for income taxes and recording the related income tax assets and liabilities. The Company recognizes the financial statement benefit of a tax position only after determining that the relevant tax authority would more-likely-than-not sustain the position following an audit. For tax positions meeting the more-likely-than-not criterion, the amount recognized in the financial statements is the largest benefit that has a greater than 50 percent likelihood of being realized upon ultimate settlement with the relevant tax authority.
	The following table summarizes activity related to the Company's gross unrecognized tax benefits, excluding interest and penalties, from January 1 to December 31, 2014, 2013 and 2012 (in thousands):
			Year Ended December 31,
			2014				2013				2012
	Beginning Balance		$	110,305			$	85,481			$	55,127
Increases related to prior year tax positions		5,489				10,494				602
Decreases related to prior year tax positions		(27,875		)		(2,103		)		(790		)
Increases related to current year tax positions		17,348				14,565				29,465
Foreign currency translation		(6,946		)		1,868				1,077
Ending Balance		$	98,321			$	110,305			$	85,481
The total amount of unrecognized tax benefits as of December 31, 2014, 2013 and 2012 that, if recognized, would affect the effective tax rate are $72.3 million, $80.0 million, and $39.3 million, respectively.
The Company recognized $1.1 million, $3.3 million and $2.3 million of interest and penalties within "Provision for income taxes" on its consolidated statements of operations for the years ended December 31, 2014, 2013 and 2012, respectively. Total accrued interest and penalties as of December 31, 2014 and 2013 was $5.7 million and $5.3 million, respectively, and were included in "Other non-current liabilities."
The Company is currently under IRS audit for the 2011 and 2012 tax years. Additionally, the Company is currently under audit by several foreign jurisdictions. It is likely that the examination phase of some of these audits will conclude in the next 12 months. The tax years 2009 to 2013 remain open to examination by the major taxing jurisdictions in which the Company is subject to tax. For the year ended December 31, 2014, the Company decreased its liabilities for uncertain tax positions and income tax expense by $21.0 million and $16.7 million, respectively, due to the expiration of the applicable statute of limitations in a foreign jurisdiction. For the year ended December 31, 2014, the Company also decreased its liabilities for uncertain tax positions and income tax expense by $7.7 million as a result of new information that impacted its estimate of the amount that is more-likely-than-not of being realized upon ultimate settlement of a tax position. As of December 31, 2014, the Company believes that it is reasonably possible that additional changes of up to $15.6 million in unrecognized tax benefits may occur within the next 12 months.
In general, it is the practice and intention of the Company to reinvest the earnings of its non-U.S. subsidiaries in those operations. As of December 31, 2014, no provision has been made for U.S. income taxes and foreign withholding taxes related to the undistributed earnings of the Company's foreign subsidiaries of approximately $271.1 million, because those undistributed earnings are indefinitely reinvested outside the United States. The actual U.S. tax cost would depend on income tax laws and circumstances at the time of distribution. Determination of the amount of unrecognized U.S. deferred tax liability related to the undistributed earnings of the Company's foreign subsidiaries is not practical due to the complexities associated with the calculation.
As of December 31, 2014, the unamortized tax effects of intercompany transactions of $14.2 million is included within "Prepaid expenses and other current assets" on the consolidated balance sheet. As of December 31, 2013, unamortized tax effects of intercompany transactions of $28.5 million and $20.4 million are included within "Prepaid expenses and other current assets" and "Other non-current assets," respectively, on the consolidated balance sheet. As of December 31, 2014, the estimated future amortization of the tax effects of intercompany transactions to income tax expense is $14.2 million for 2015. This amount excludes the benefits, if any, for tax deductions in other jurisdictions that the Company may be entitled to as a result of the related intercompany transactions.

Variable_Interest_Entity_Notes

Variable Interest Entity (Notes)	12 Months Ended
	Dec. 31, 2014
Variable Interest Entity [Abstract]
Variable Interest Entity Disclosure	VARIABLE INTEREST ENTITY
	The Company entered into a collaborative arrangement to create a jointly-owned sales category with a strategic partner ("Partner"), and a limited liability company ("LLC") was established in 2011. The Company and its Partner each owns 50% of the LLC, and income and cash flows of the LLC are allocated based on agreed upon percentages between the Company and the Partner. The liabilities of the LLC are solely the LLC's obligations and are not obligations of the Company or the Partner.
	The Company's obligations associated with its interests in the LLC are primarily building, maintaining, customizing, managing and operating the website, contributing intellectual property, identifying deals and promoting the sale of deal vouchers, coordinating the fulfillment of deal vouchers in certain instances and providing the record keeping.
	Under the LLC agreement, the LLC shall be dissolved upon the occurrence of any of the following events: (1) either party becoming a majority owner; (2) the third anniversary of the date of the LLC agreement; (3) certain elections of the Company or the Partner based on the operational and financial performance of the LLC or other changes to certain terms in the agreement; (4) election of either the Company or the Partner in the event of bankruptcy by the other party; (5) sale of the LLC; or (6) a court's dissolution of the LLC. The LLC agreement was subsequently amended to extend the contractual dissolution date to May 2016.
	Variable interest entities ("VIEs") are entities that have either a total equity investment that is insufficient to permit the entity to finance its activities without additional subordinated financial support, or whose equity investors lack the characteristics of a controlling financial interest (i.e., the ability to make significant decisions through voting rights and the right to receive the expected residual returns of the entity or the obligation to absorb the expected losses of the entity). A variable interest holder that has both (a) the power to direct the activities of the VIE that most significantly impact its economic performance and (b) either an obligation to absorb losses or a right to receive benefits that could potentially be significant to the VIE is referred to as the primary beneficiary and must consolidate the VIE.
	The Company has determined that the LLC is a VIE and the Company is its primary beneficiary. The Company consolidates the LLC because it has the power to direct the activities of the LLC that most significantly impact the LLC's economic performance. In particular, the Company identifies and promotes the deal vouchers, provides all of the back office support (i.e. website, contracts, personnel resources, accounting, etc.), presents the LLC's deal offerings via the Company's website, mobile application and email and provides the editorial resources that create the verbiage included on the website with the LLC's deal offers.

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2014
FAIR VALUE MEASUREMENTS [Abstract]
Fair Value Measurements [Text Block]	FAIR VALUE MEASUREMENTS
	Fair value is defined under U.S. GAAP 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. As such, fair value is a market-based measurement that is determined based on assumptions that market participants would use in pricing an asset or a liability.
	To increase the comparability of fair value measures, the following hierarchy prioritizes the inputs in valuation methodologies used to measure fair value:
	Level 1 - Measurements that reflect quoted prices (unadjusted) for identical assets or liabilities in active markets.
	Level 2 - Measurements that include other inputs that are directly or indirectly observable in the marketplace.
	Level 3 - Measurements derived from valuation techniques in which one or more significant inputs or significant value drivers are unobservable. These fair value measurements require significant judgment.
	In determining fair value, the Company uses various valuation approaches within the fair value measurement framework. The valuation methodologies used for the Company's assets and liabilities measured at fair value and their classification in the valuation hierarchy are summarized below:
	Cash equivalents - Cash equivalents primarily consist of AAA-rated money market funds with overnight liquidity and no stated maturities. The Company classified cash equivalents as Level 1 due to the short-term nature of these instruments and measured the fair value based on quoted prices in active markets for identical assets.
	Available-for-sale securities - The Company has investments in redeemable preferred shares and convertible debt securities issued by nonpublic entities. The Company measures the fair value of available-for-sale securities using the discounted cash flow method, which is an income approach, and the probability-weighted expected return method, which is an income approach that incorporates probability-weighted outcomes.
	The Company has classified its investments in available-for-sale securities as Level 3 due to the lack of observable market data over fair value inputs such as cash flow projections, discount rates and probability-weightings. Increases in projected cash flows and decreases in discount rates contribute to increases in the estimated fair values of available-for-sale securities, whereas decreases in projected cash flows and increases in discount rates contribute to decreases in their fair values. Additionally, increases in the probabilities of favorable investment outcomes, such as a sale or initial public offering of the investee, and decreases in the probabilities of unfavorable outcomes, such as a default by the investee, contribute to increases in the estimated fair value of available-for-sale securities, whereas decreases in the probabilities of favorable investment outcomes and increases in the probabilities of unfavorable investment outcomes contribute to decreases in their fair values.
	Contingent consideration - The Company has contingent obligations to transfer cash or shares to the former owners of acquired businesses if specified financial results are met over future reporting periods (i.e. earn-outs). The Company also has a contingent obligation to transfer up to $1.1 million of cash or shares to the former owners of an acquired business if the Company's share price is less than $6.48 per share on June 8, 2015. Liabilities for contingent consideration are measured at fair value each reporting period, with the acquisition-date fair value included as part of the consideration transferred and subsequent changes in fair value are recorded in earnings within "Acquisition-related expense (benefit), net" on the consolidated statements of operations.
	The Company uses an income approach to value contingent consideration obligations based on future financial performance, which is determined based on the present value of probability-weighted future cash flows. The Company has generally classified the contingent consideration liabilities as Level 3 due to the lack of relevant observable market data over fair value inputs such as probability-weighting of payment outcomes. Increases in the assessed likelihood of a higher payout under a contingent consideration arrangement contribute to increases in the fair value of the related liability. Conversely, decreases in the assessed likelihood of a higher payout under a contingent consideration arrangement contribute to decreases in the fair value of the related liability. The Company uses a Black-Scholes-Merton option pricing model to value the contingent consideration obligation that is payable upon declines in the Company's share price. Increases in volatility and decreases in the Company's share price contribute to the increases in the fair value of that contingent consideration liability. Conversely, decreases in volatility and increases in the Company's share price contribute to decreases in the fair value of the contingent consideration liability. Changes in assumptions could have an impact on the payout of contingent consideration arrangements with a maximum payout of $8.4 million.
	The following tables summarize the Company's assets and liabilities that are measured at fair value on a recurring basis (in thousands):
						Fair Value Measurement at Reporting Date Using
	Description	31-Dec-14				Quoted Prices in Active Markets for				Significant Other				Significant
						Identical Assets				Observable				Unobservable
						(Level 1)				Inputs				Inputs
										(Level 2)				(Level 3)
	Assets:
	Cash equivalents	$	440,596			$	440,596			$	—			$	—
	Available-for-sale securities:
	Convertible debt securities	2,527				—				—				2,527
	Redeemable preferred shares	4,910				—				—				4,910
	Liabilities:
	Contingent consideration	1,983				—				—				1,983
						Fair Value Measurement at Reporting Date Using
	Description	31-Dec-13				Quoted Prices in Active Markets for				Significant Other				Significant
						Identical Assets				Observable				Unobservable
						(Level 1)				Inputs				Inputs
										(Level 2)				(Level 3)
	Assets:
	Cash equivalents	$	585,514			$	585,514			$	—			$	—
	Available-for-sale securities:
	Convertible debt securities	3,174				—				—				3,174
	Redeemable preferred shares	—				—				—				—
	Liabilities:
	Contingent consideration	606				—				—				606
	The following table provides a roll-forward of the fair value of recurring Level 3 fair value measurements for the years ended December 31, 2014, 2013 and 2012 (in thousands):
			Year Ended December 31,
			2014				2013				2012
	Assets
	Available-for-sale securities
	Convertible debt securities:
	Beginning Balance		$	3,174			$	3,087			$	—
	Purchases of convertible debt securities		—				370				3,000
	Total gains (losses) included in other comprehensive income		693				(283		)		87
	Total gains (losses) included in other expense, net		(1,340		)		—				—
	Ending Balance		$	2,527			$	3,174			$	3,087
	Unrealized (losses) gains still held(1)		$	(647	)		$	(283	)		$	87
	Redeemable preferred shares:
	Beginning Balance		$	—			$	42,539			$	—
	Acquisitions of preferred shares in exchange transactions (See note 6)		—				34,982				56,940
	Purchase of redeemable preferred shares		4,599				8,000				—
	Total gains included in other comprehensive income		311				—				—
	Other-than-temporary impairments included in earnings		—				(85,521		)		(14,401		)
	Ending Balance		$	4,910			$	—			$	42,539
	Unrealized (losses) gains still held(1)		$	311			$	(85,521	)		$	(14,401	)
	Liabilities
	Contingent Consideration:
	Beginning Balance		$	606			$	7,601			$	11,230
	Issuance of contingent consideration in connection with acquisitions		4,388				3,567				3,400
	Settlements of contingent consideration liabilities		(424		)		(4,377		)		(4,936		)
	Reclass to non-fair value liabilities when no longer contingent		(143		)		(3,014		)		(4,978		)
	Total (gains) losses included in earnings(2)		(2,444		)		(3,171		)		897
Reclass of contingent consideration from Level 2 to Level 3		—				—				1,988
Ending Balance		$	1,983			$	606			$	7,601
Unrealized (gains) losses still held(1)		$	(2,405	)		$	360			$	211
-1	Represents the unrealized losses or gains recorded in earnings and/or other comprehensive income (loss) during the period for assets and liabilities classified as Level 3 that are still held (or outstanding) at the end of the period.
-2	Changes in the fair value of contingent consideration liabilities are classified within "Acquisition-related expense (benefit), net" on the consolidated statements of operations.
Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis
Certain assets and liabilities are measured at fair value on a nonrecurring basis, including assets that are written down to fair value as a result of an impairment. The Company did not record any significant nonrecurring fair value measurements after initial recognition for the years ended December 31, 2014 and 2013. The following table summarizes the Company's assets that were measured at fair value on a nonrecurring basis as of December 31, 2012 (in thousands):
					Fair Value Measurement at Reporting Date Using
Description	31-Dec-12				Quoted Prices				Significant				Significant
					in Active				Other				Unobservable
					Markets for				Observable				Inputs
					Identical				Inputs				(Level 3)
					Assets				(Level 2)
					(Level 1)
Asset impairments:
Cost method investment in Life Media Limited (F-tuan) common shares	$	34,982			$	—			$	—			$	34,982
Equity method investment	$	495			$	—			$	—			$	495
Estimated Fair Value of Financial Assets and Liabilities Not Measured at Fair Value
The following table presents the carrying amounts and fair values of financial instruments that are not carried at fair value in the consolidated financial statements (in thousands):
		31-Dec-14								31-Dec-13
		Carrying Amount				Fair Value				Carrying Amount				Fair Value
Cost method investments		$	15,630			$	16,134			$	15,788			$	15,573
The fair values of the Company's cost method investments were determined using the market approach or the income approach, depending on the availability of fair value inputs such as financial projections for the investees and market multiples for comparable companies. The Company has classified the fair value measurements of its cost method investments as Level 3 measurements within the fair value hierarchy because they involve significant unobservable inputs such as cash flow projections and discount rates.
The Company's other financial instruments not carried at fair value consist primarily of short term certificates of deposit, accounts receivable, restricted cash, accounts payable, accrued merchant and supplier payables and accrued expenses. The carrying values of these assets and liabilities approximate their respective fair values as of December 31, 2014 and 2013 due to their short term nature.

Loss_Per_Share_of_Class_A_and_

Loss Per Share of Class A and Class B Common Stock	12 Months Ended
	Dec. 31, 2014
LOSS PER SHARE OF CLASS A AND CLASS B COMMON STOCK [Abstract] [Abstract]
Loss Per Share of Class A and Class B Common Stock [Text Block]	LOSS PER SHARE OF CLASS A AND CLASS B COMMON STOCK
	The Company computes loss per share of Class A and Class B common stock using the two-class method. Basic loss per share is computed using the weighted-average number of common shares outstanding during the period. Diluted loss per share is computed using the weighted-average number of common shares and the effect of potentially dilutive equity awards outstanding during the period. Potentially dilutive securities consist of stock options, restricted stock units, unvested restricted stock awards, performance share units and ESPP shares. The dilutive effect of these equity awards are reflected in diluted loss per share by application of the treasury stock method. The computation of the diluted loss per share of Class A common stock assumes the conversion of Class B common stock, if dilutive, while the diluted loss per share of Class B common stock does not assume the conversion of those shares.
	The rights, including the liquidation and dividend rights, of the holders of Class A and Class B common stock are identical, except with respect to voting. Under the two-class method, the undistributed earnings for each period are allocated based on the contractual participation rights of the Class A and Class B common shares as if the earnings for the period had been distributed. As the liquidation and dividend rights are identical, the undistributed earnings are allocated on a proportionate basis. Further, as the Company assumes the conversion of Class B common stock, if dilutive, in the computation of the diluted loss per share of Class A common stock, the undistributed earnings are equal to net income for that computation.
	The following table sets forth the computation of basic and diluted loss per share of Class A and Class B common stock for the years ended December 31, 2014, 2013 and 2012 (in thousands, except share amounts and per share amounts):
			Year Ended December 31,
			2014							2013						2012
			Class A				Class B			Class A			Class B			Class A			Class B
	Basic loss per share:
	Numerator
	Allocation of net loss		$	(63,691	)		$	(228	)	$	(88,626	)	$	(320	)	$	(50,842	)	$	(189	)
	Less: Allocation of adjustment of redeemable noncontrolling interests to redemption value		—				—			—			—			12,557			47
	Less: Allocation of net income attributable to noncontrolling interests		9,138				33			6,424			23			3,728			14
	Allocation of net loss attributable to common stockholders		$	(72,829	)		$	(261	)	$	(95,050	)	$	(343	)	$	(67,127	)	$	(250	)
	Denominator
	Weighted-average common shares outstanding		672,432,417				2,399,976			661,510,218			2,399,976			647,814,143			2,399,976
	Basic loss per share		$	(0.11	)		$	(0.11	)	$	(0.14	)	$	(0.14	)	$	(0.10	)	$	(0.10	)
	Diluted loss per share:
	Numerator
	Allocation of net loss attributable to common stockholders		$	(72,829	)		$	(261	)	$	(95,050	)	$	(343	)	$	(67,127	)	$	(250	)
	Reallocation of net income attributable to common stockholders as a result of conversion of Class B(1)		—				—			—			—			—			—
	Allocation of net loss attributable to common stockholders		$	(72,829	)		$	(261	)	$	(95,050	)	$	(343	)	$	(67,127	)	$	(250	)
	Denominator
	Weighted-average common shares outstanding used in basic computation		672,432,417				2,399,976			661,510,218			2,399,976			647,814,143			2,399,976
	Conversion of Class B(1)		—				—			—			—			—			—
	Employee stock options(1)		—				—			—			—			—			—
	Restricted shares and RSUs(1)		—				—			—			—			—			—
	Weighted-average diluted shares outstanding(1)		672,432,417				2,399,976			661,510,218			2,399,976			647,814,143			2,399,976
	Diluted loss per share		$	(0.11	)		$	(0.11	)	$	(0.14	)	$	(0.14	)	$	(0.10	)	$	(0.10	)
	-1	Conversion of Class B shares into Class A shares and outstanding equity awards have not been reflected in the diluted loss per share calculation for the years ended December 31, 2014, 2013 and 2012 because the effect would be antidilutive.
	The following outstanding equity awards are not included in the diluted loss per share calculation above because they would have had an antidilutive effect:
			Year Ended December 31,
			2014			2013			2012
	Stock options		2,775,771			5,594,033			7,713,421
	Restricted stock units		42,341,320			39,618,897			29,699,348
	Restricted stock		52,854			298,292			577,048
	ESPP shares		507,916			444,439			271,402
	Total		45,677,861			45,955,661			38,261,219
	In addition to the antidilutive awards as set forth in the table above, the Company also granted approximately 2,000,000 performance share units in connection with its acquisition of Ticket Monster during the year ended December 31, 2014. Contingently issuable shares are excluded from the computation of diluted EPS if, based on current period results, the shares would not be issuable if the end of the reporting period were the end of the contingency period. These outstanding performance share units have been excluded from the table above for the year ended December 31, 2014 as the performance conditions were not satisfied as of the end of the period.

Segment_Information

Segment Information	12 Months Ended
	Dec. 31, 2014
SEGMENT INFORMATION [Abstract]
Segment Reporting Disclosure [Text Block]	SEGMENT INFORMATION
	The company organizes its operations into three segments: North America, EMEA, which is comprised of Europe, Middle East and Africa, and the remainder of the Company's international operations ("Rest of World"). Segment operating results reflect earnings before stock-based compensation, acquisition-related expense (benefit), net, other expense, net and provision for income taxes. Segment information reported in the tables below represents the operating segments of the Company organized in a manner consistent with which separate information is available and for which segment results are evaluated regularly by the Company's chief operating decision-maker in assessing performance and allocating resources.
	Revenue and profit or loss information by reportable segment reconciled to consolidated net loss for the years ended December 31, 2014, 2013 and 2012 were as follows (in thousands):
			Year Ended December 31,
			2014				2013				2012
	North America
	Revenue(1)		$	1,824,461			$	1,521,358			$	1,165,700
	Segment cost of revenue and operating expenses(2)		1,755,113				1,380,746				1,025,974
	Segment operating income(2)		69,348				140,612				139,726
	EMEA
	Revenue(1)		961,130				742,915				805,476
	Segment cost of revenue and operating expenses(2)		857,062				631,409				699,470
	Segment operating income(2)		104,068				111,506				106,006
	Rest of World
	Revenue		406,097				309,382				363,296
	Segment cost of revenue and operating expenses(2)		471,067				364,295				405,313
	Segment operating loss(2)		(64,970		)		(54,913		)		(42,017		)
	Consolidated
	Revenue		3,191,688				2,573,655				2,334,472
	Segment cost of revenue and operating expenses(2)		3,083,242				2,376,450				2,130,757
	Segment operating income(2)		108,446				197,205				203,715
	Stock-based compensation		122,019				121,462				104,117
	Acquisition-related expense (benefit), net		1,269				(11		)		897
	(Loss) income from operations		(14,842		)		75,754				98,701
	Other expense, net		(33,353		)		(94,663		)		(3,759		)
	(Loss) income before provision for income taxes		(48,195		)		(18,909		)		94,942
	Provision for income taxes		15,724				70,037				145,973
	Net loss		$	(63,919	)		$	(88,946	)		$	(51,031	)
	-1	North America includes revenue from the United States of $1,784.6 million, $1,471.9 million and $1,108.4 million for the years ended December 31, 2014, 2013 and 2012 respectively. Beginning in September 2013, direct revenue transactions in the EMEA Goods category have been transacted through a Switzerland-based subsidiary. As a result, EMEA includes revenue from Switzerland of $468.7 million for the year ended December 31, 2014. There were no other individual countries that represented more than 10% of consolidated total revenue for the years ended December 31, 2014, 2013 or 2012.
	-2	Segment cost of revenue and operating expenses and segment operating income (loss) exclude stock-based compensation and acquisition-related (benefit) expense, net. This presentation corresponds to the measure of segment profit or loss that the Company's chief operating decision-maker uses in assessing segment performance and making resource allocation decisions. The following table summarizes the Company's stock-based compensation expense and acquisition-related expense (benefit), net by reportable segment for the years ended December 31, 2014, 2013 and 2012. (in thousands):
			Year Ended December 31,
			2014								2013								2012
			Stock-based compensation				Acquisition-related				Stock-based compensation				Acquisition-related				Stock-based compensation			Acquisition-related
	North America		$	99,939			$	1,125			$	90,877			$	1,285			$	65,127		$	(2,780	)
	EMEA		9,927				144				16,263				(1,296		)		15,123			3,677
	Rest of World		12,153				—				14,322				—				23,867			—
	Consolidated		$	122,019			$	1,269			$	121,462			$	(11	)		$	104,117		$	897
	Acquisition-related expense (benefit), net for the North America segment includes external transaction costs and gains and losses relating to contingent consideration obligations incurred by U.S. legal entities relating to purchases of businesses that became part of the EMEA and Rest of World segments, which is consistent with the attribution used for internal reporting purposes.
	The following table summarizes the Company's total assets by reportable segment as of December 31, 2014 and 2013 (in thousands):
		December 31,
		2014				2013
	North America (1)	$	1,150,417			$	1,267,158
	EMEA	552,486				616,126
	Rest of World (1)	524,694				158,726
	Consolidated total assets	$	2,227,597			$	2,042,010
	-1	North America contains assets from the United States of $1,120.4 million and $1,231.3 million as of December 31, 2014 and 2013, respectively. Rest of World contains assets from the Republic of Korea, including those assets acquired as a part of our acquisition of Ticket Monster described in Note 3 "Business Combinations," of $388.0 million as of December 31, 2014. There were no other individual countries that represented more than 10% of consolidated total assets as of December 31, 2014 and 2013, respectively.
	The following table summarizes the Company's tangible property and equipment, net of accumulated depreciation and amortization, by reportable segment as of December 31, 2014 and 2013 (in thousands):
		December 31,
		2014				2013
	North America (1)	$	63,915			$	43,126
	EMEA (2)	28,721				23,413
	Rest of World	11,167				9,100
	Consolidated total	$	103,803			$	75,639
	-1	Substantially all tangible property and equipment within North America is located in the United States.
	-2	Tangible property and equipment, net located within Ireland represented approximately 12% of the Company's consolidated tangible property and equipment, net as of December 31, 2014. Tangible property and equipment, net located within Switzerland represented approximately 11% of the Company's consolidated tangible property and equipment, net as of December 31, 2013. There were no other individual countries located outside of the United States that represented more than 10% of consolidated tangible property and equipment, net as of December 31, 2014 and 2013.
	The following table summarizes depreciation and amortization of property, equipment and software and intangible assets by reportable segment for the years ended December 31, 2014, 2013 and 2012 (in thousands):
		Year Ended December 31,
		2014				2013				2012
	North America	$	83,106			$	57,700			$	30,580
	EMEA	24,849				24,157				17,546
	Rest of World	36,966				7,592				7,675
	Consolidated total	$	144,921			$	89,449			$	55,801
	The following table summarizes the Company's expenditures for additions to tangible long-lived assets by reportable segment for the years ended December 31, 2014, 2013 and 2012 (in thousands):
		Year Ended December 31,
	2014				2013				2012
North America	$	6,775			$	14,728			$	38,543
EMEA	12,945				6,719				26,909
Rest of World	11,616				7,469				3,875
Consolidated total	$	31,336			$	28,916			$	69,327
The Company's equity method investments as of December 31, 2014 and 2013 were $1.2 million and $1.7 million, respectively, which are included in North America and are held by an entity in the United States.
Category Information
The Company offers goods and services through three primary categories: Local Deals ("Local"), Groupon Goods ("Goods") and Groupon Getaways ("Travel"). The Company also earns advertising revenue, payment processing revenue, point of sale revenue and commission revenue. Revenue and gross profit from these other sources were previously considered to be distinct from our primary categories and were aggregated with revenue and gross profit from Travel, our smallest category. In recent periods, these other revenue sources have been increasingly viewed by management as a component of the Local category, as they are primarily generated through the Company's relationships with local and national merchants. Accordingly, the Company updated its presentation of category information, effective beginning with the quarter ended March 31, 2014, to include other revenue and gross profit within the Local category in the tables below, and the prior period category information has been retrospectively adjusted to conform to the current period presentation.
The following table summarizes the Company's third party and other and direct revenue by category for its three reportable segments for the years ended December 31, 2014, 2013 and 2012 (in thousands):
	North America												EMEA											Rest of World									Consolidated
	Year Ended												Year Ended											Year Ended									Year Ended
	December 31,												December 31,											December 31,									December 31,
	2014				2013				2012				2014				2013			2012				2014			2013			2012			2014		2013			2012
Local (1):
Third party and other	$	674,605			$	671,846			$	665,587			$	391,179			$	430,020		$	501,782			$	167,552		$	182,010		$	221,859		$	1,233,336	$	1,283,876		$	1,389,228
Direct	—				1,772				12,037				—				—			—				—			—			—			—		1,772			12,037
Total	674,605				673,618				677,624				391,179				430,020			501,782				167,552			182,010			221,859			1,233,336		1,285,648			1,401,265
Goods:
Third party	5,966				17,409				60,269				63,650				133,117			186,495				146,984			69,344			87,746			216,600		219,870			334,510
Direct	1,074,913				774,023				391,239				442,344				115,881			36,393				46,892			27,325			10,821			1,564,149		917,229			438,453
Total	1,080,879				791,432				451,508				505,994				248,998			222,888				193,876			96,669			98,567			1,780,749		1,137,099			772,963
Travel:
Third party	68,977				56,308				36,568				63,957				63,897			76,553				44,669			30,703			42,870			177,603		150,908			155,991
Direct	—				—				—				—				—			4,253				—			—			—			—		—			4,253
Total	68,977				56,308				36,568				63,957				63,897			80,806				44,669			30,703			42,870			177,603		150,908			160,244
Total revenue	$	1,824,461			$	1,521,358			$	1,165,700			$	961,130			$	742,915		$	805,476			$	406,097		$	309,382		$	363,296		$	3,191,688	$	2,573,655		$	2,334,472
-1	Includes revenue from deals with local and national merchants and through local events.
The following table summarizes the Company's gross profit by category for its three reportable segments for the years ended December 31, 2014, 2013 and 2012 (in thousands):
	North America												EMEA											Rest of World									Consolidated
	Year Ended												Year Ended											Year Ended									Year Ended
	December 31,												December 31,											December 31,									December 31,
	2014				2013				2012				2014				2013			2012				2014			2013			2012			2014		2013			2012
Local (1):
Third party and other	$	581,067			$	582,723			$	541,716			$	364,545			$	383,725		$	453,970			$	138,527		$	153,406		$	173,735		$	1,084,139	$	1,119,854		$	1,169,421
Direct	—				(782		)		1,909				—				—			—				—			—			—			—		(782		)	1,909
Total	581,067				581,941				543,625				364,545				383,725			453,970				138,527			153,406			173,735			1,084,139		1,119,072			1,171,330
Goods:
Third party	5,112				15,319				48,288				55,434				116,357			168,429				91,486			39,699			66,271			152,032		171,375			282,988
Direct	88,810				66,753				36,188				77,706				13,194			(2,521		)		(2,984		)	(224		)	(2,563		)	163,532		79,723			31,104
Total	93,922				82,072				84,476				133,140				129,551			165,908				88,502			39,475			63,708			315,564		251,098			314,092
Travel:
Third party	56,994				48,824				27,208				59,229				56,850			68,777				33,260			25,689			33,596			149,483		131,363			129,581
Direct	—				—				—				—				—			529				—			—			—			—		—			529
Total	56,994				48,824				27,208				59,229				56,850			69,306				33,260			25,689			33,596			149,483		131,363			130,110
Total gross profit	$	731,983			$	712,837			$	655,309			$	556,914			$	570,126		$	689,184			$	260,289		$	218,570		$	271,039		$	1,549,186	$	1,501,533		$	1,615,532
-1	Includes gross profit from deals with local and national merchants and through local events.

Related_Party_Transactions_Not

Related Party Transactions (Notes)	12 Months Ended
	Dec. 31, 2014
Related Party Transactions [Abstract]
Related Party Transactions Disclosure [Text Block]	RELATED PARTY TRANSACTIONS
	Business Combination
	During 2013, the Company acquired Boomerang, Inc., a Lightbank LLC portfolio company, for total cash consideration of $1.0 million. Eric Lefkofsky, the Company's current CEO and former Chairman, and Bradley Keywell, one of the Company's directors, co-founded Lightbank, a private investment firm specializing in information technology companies. They are the majority shareholders of Lightbank, and Mr. Keywell is the managing director.
	Marketing Services
	During 2011, the Company engaged InnerWorkings, Inc. ("InnerWorkings") to provide marketing services.  At that time Eric Lefkofsky was the Executive Chairman and a significant stockholder of InnerWorkings. Mr. Lefkofsky is no longer a director nor a significant stockholder in InnerWorkings.  The Company recognized $1.1 million of expense under its agreement with InnerWorkings for the year ended December 31, 2012.
	Logistics Services
	In connection with the Company's expansion of Goods offerings during 2012, the Company entered into a transportation and supply chain management agreement with Echo Global Logistics, Inc. ("Echo"). Eric Lefkofsky, Bradley Keywell and Peter Barris, one of the Company's other directors, either are currently or were previously directors of Echo and have direct and/or indirect ownership interests in Echo. The Company terminated its arrangement with Echo during 2012. Echo received payments of approximately $1.9 million for its services under the agreement for the year ended December 31, 2012, which were expensed by the Company through "Cost of revenue" on the consolidated statement of operations.

Quarterly_Results_Notes

Quarterly Results (Notes)	12 Months Ended
	Dec. 31, 2014
Quarterly Results [Abstract]
Quarterly Financial Information [Text Block]	QUARTERLY RESULTS (UNAUDITED)
	The following table represents data from the Company's unaudited consolidated statements of operations for the most recent eight quarters. This quarterly information has been prepared on the same basis as the consolidated financial statements and includes all normal recurring adjustments necessary to fairly state the information for the periods presented. The results of operations of any quarter are not necessarily indicative of the results that may be expected for any future period (in thousands, except per share amounts).
			Quarter Ended
			Dec. 31,		Sept. 30,			June 30,			Mar. 31,			Dec. 31,			Sept. 30,			June 30,			Mar. 31,
			2014		2014			2014			2014			2013			2013			2013			2013
	Consolidated Statements of Operations Data:
	Revenue		$	925,421	$	757,054		$	751,576		$	757,637		$	768,447		$	595,059		$	608,747		$	601,402
	Cost of revenue		531,962		376,910			361,714			371,916			390,239			235,437			224,053			222,393
	Gross profit		393,459		380,144			389,862			385,721			378,208			359,622			384,694			379,009
	Income (loss) from operations		18,394		(5,429		)	(7,854		)	(19,953		)	13,352			13,812			27,412			21,178
	Net income (loss) (1)		11,384		(19,018		)	(20,922		)	(35,363		)	(78,861		)	(1,292		)	(5,551		)	(3,242		)
	Net income (loss) attributable to Groupon, Inc. (1)		8,788		(21,208		)	(22,875		)	(37,795		)	(81,247		)	(2,580		)	(7,574		)	(3,992		)
	Net earnings (loss) per share
	Basic		$0.01		($0.03)			($0.03)			($0.06)			($0.12)			$0.00			($0.01)			($0.01)
	Diluted		$0.01		($0.03)			($0.03)			($0.06)			($0.12)			$0.00			($0.01)			($0.01)
	Weighted average number of shares outstanding
	Basic		671,885,967		669,526,524			675,538,392			682,378,690			668,046,073			666,432,848			662,361,436			658,800,417
	Diluted		681,543,847		669,526,524			675,538,392			682,378,690			668,046,073			666,432,848			662,361,436			658,800,417
	-1	Net loss and net loss attributable to Groupon, Inc. for the quarter ended December 31, 2013 included an impairment of the Company's investment in F-tuan of $85.5 million ($77.8 million, net of tax). See Note 6 "Investments."

Schedule_II_Valuation_and_Qual

Schedule II - Valuation and Qualifying Accounts (Notes)	12 Months Ended
	Dec. 31, 2014
Valuation and Qualifying Accounts Disclosure [Line Items]
Schedule of Valuation and Qualifying Accounts Disclosure [Text Block]	Financial Statement Schedules
	Schedule II-Valuation and Qualifying Accounts
		Balance at		Charged to		Acquisitions			Balance at End
		Beginning of		Expense		and Other			of Year
		Year
		(in thousands)
	TAX VALUATION ALLOWANCE:
	Year ended December 31, 2014	$	173,577	$	23,515	$	8,394		$	205,486
	Year ended December 31, 2013	159,249		24,404		(10,076		)	173,577
	Year ended December 31, 2012	128,215		27,751		3,283			159,249
	All other schedules have been omitted because they are either inapplicable or the required information has been provided in the consolidated financial statements or in the notes thereto.
	(3) Exhibits (i)  See the Exhibit Index immediately following the signature page of this Annual Report on Form 10-K.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Summary of Significant Accounting Policies [Abstract]
Consolidation, Policy [Policy Text Block]	Principles of Consolidation
	The consolidated financial statements include the accounts of the Company and its subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. The Company's consolidated financial statements were prepared in accordance with U.S. generally accepted accounting principles ("U.S. GAAP") and include the assets, liabilities, revenue and expenses of all wholly‑owned subsidiaries and majority‑owned subsidiaries over which the Company exercises control and variable interest entities for which the Company has determined that it is the primary beneficiary. Outside stockholders' interests in subsidiaries are shown on the consolidated financial statements as "Noncontrolling interests." Equity investments in entities in which the Company does not have a controlling financial interest are accounted for under either the equity method, the cost method or as available-for-sale securities, as appropriate.
Reclassification, Policy [Policy Text Block]	Reclassifications
	Certain reclassifications have been made to the consolidated financial statements of prior years and the accompanying notes to conform to the current year presentation.
Use of Estimates, Policy [Policy Text Block]	Use of Estimates
	The preparation of consolidated financial statements in conformity with U.S. GAAP requires estimates and assumptions that affect the reported amounts and classifications of assets and liabilities, revenue and expenses, and the related disclosures of contingent liabilities in the consolidated financial statements and accompanying notes. Estimates are utilized for, but not limited to, stock‑based compensation, income taxes, valuation of acquired goodwill and intangible assets, investments, customer refunds, contingent liabilities and the useful lives of property, equipment and software and intangible assets. Actual results could differ materially from those estimates.
Cash and Cash Equivalents, Policy [Policy Text Block]	Cash and Cash Equivalents
	The Company considers all highly‑liquid investments with an original maturity of three months or less from the date of purchase to be cash equivalents. The Company's cash equivalents primarily include holdings in money market funds and overnight securities.
Receivables, Trade and Other Accounts Receivable, Allowance for Doubtful Accounts, Policy [Policy Text Block]	Accounts Receivable, Net
	Accounts receivable primarily represents the net cash due from the Company's credit card and other payment processors for cleared transactions. The carrying amount of the Company's receivables is reduced by an allowance for doubtful accounts that reflects management's best estimate of amounts that will not be collected. The allowance is based on historical loss experience and any specific risks identified in collection matters. Accounts receivable are charged off against the allowance for doubtful accounts when it is determined that the receivable is uncollectible. The Company's allowance for doubtful accounts as of December 31, 2014 and 2013 was $2.2 million and $0.7 million, respectively. Bad debt expense for the years ended December 31, 2014, 2013 and 2012 was $2.3 million, $0.7 million and $0.6 million, respectively.
Inventory, Policy [Policy Text Block]	Inventories
	Inventories, consisting of merchandise purchased for resale, are accounted for using the first-in-first-out ("FIFO") method of accounting and are valued at the lower of cost or market value. The Company writes down its inventory for estimated obsolescence and to the lower of cost or market value based upon assumptions about future demand and market conditions. If actual market conditions are less favorable than those projected by management, additional inventory write-downs may be required. Once established, the original cost of the inventory less the related inventory allowance represents a new cost basis.
Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block]	Restricted Cash
	The Company had $12.0 million and $5.2 million of restricted cash recorded within "Prepaid expenses and other current assets" and "Other non-currents assets," respectively, as of December 31, 2014. The Company had $14.6 million and $0.4 million of restricted cash recorded within "Prepaid expenses and other current assets" and "Other non-currents assets," respectively, as of December 31, 2013. Restricted cash primarily represents amounts that the Company is unable to access for operational purposes pursuant to contractual arrangements with certain financial institutions and with entities that process merchant payments on the Company's behalf.
Internal Use Software, Policy [Policy Text Block]	Internal-Use Software
	The Company incurs costs related to internal-use software and website development, including purchased software and internally-developed software. Costs incurred in the planning and evaluation stage of internally-developed software and website development are expensed as incurred. Costs incurred and accumulated during the application development stage are capitalized and included within "Property, equipment and software, net" on the consolidated balance sheets. Capitalized internally-developed software and website development costs are amortized over their expected economic life of two years using the straight-line method.
Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block]	Goodwill
	Goodwill is allocated to the Company's reporting units at the date the goodwill is initially recorded. Once goodwill has been allocated to the reporting units, it no longer retains its identification with a particular acquisition and becomes identified with the reporting unit in its entirety. Accordingly, the fair value of the reporting unit as a whole is available to support the recoverability of its goodwill.
	The Company evaluates goodwill for impairment annually on October 1 or more frequently when an event occurs or circumstances change that indicates the carrying value may not be recoverable. The Company has the option to assess goodwill for impairment by first performing a qualitative assessment to determine whether it is more-likely-than-not that the fair value of a reporting unit is less than its carrying amount. If the Company determines that it is not more-likely-than-not that the fair value of a reporting unit is less than its carrying amount, then further goodwill impairment testing is not required to be performed. If the Company determines that it is more-likely-than-not that the fair value of a reporting unit is less than its carrying amount, or if the Company does not elect the option to perform an initial qualitative assessment, the Company is required to perform a two-step goodwill impairment test. In the first step, the fair value of the reporting unit is compared to its book value including goodwill. If the fair value of the reporting unit is in excess of its book value, the related goodwill is not impaired and no further analysis is necessary. If the fair value of the reporting unit is less than its book value, there is an indication of potential impairment and a second step is performed. When required, the second step of testing involves calculating the implied fair value of goodwill for the reporting unit. The implied fair value of goodwill is determined in the same manner as goodwill recognized in a business combination, which is the excess of the fair value of the reporting unit determined in step one over the fair value of its net assets and identifiable intangible assets as if the reporting unit had been acquired. If the carrying value of the reporting unit's goodwill exceeds the implied fair value of that goodwill, an impairment loss is recognized in an amount equal to that excess. For reporting units with a negative book value (i.e., excess of liabilities over assets), qualitative factors are evaluated to determine whether it is necessary to perform the second step of the goodwill impairment test.
Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]	Impairment of Long-Lived Assets
	Long‑lived assets, such as property, equipment and software and intangible assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset or asset group may not be recoverable. If circumstances require that a long‑lived asset or asset group be tested for possible impairment, the Company first compares the undiscounted cash flows expected to be generated by that long-lived asset or asset group to its carrying amount. If the carrying amount of the long‑lived asset or asset group is not recoverable on an undiscounted cash flow basis, an impairment is recognized to the extent that the carrying amount exceeds its fair value.
Investment, Policy [Policy Text Block]	Investments
	Investments in nonmarketable equity shares with no redemption provisions that are not common stock or in-substance common stock or for which the Company does not have the ability to exercise significant influence are accounted for using the cost method of accounting and classified within "Investments" on the consolidated balance sheets. Under the cost method of accounting, investments are carried at cost and are adjusted only for other-than-temporary declines in fair value, certain distributions and additional investments.
	Investments in common stock or in-substance common stock for which the Company has the ability to exercise significant influence are accounted for under the equity method and classified within "Investments" on the consolidated balance sheets. The Company's proportionate share of income or loss on equity method investments is presented within "Other expense, net" on the consolidated statements of operations.
	The Company has investments in convertible debt securities and convertible redeemable preferred shares issued by nonpublic entities and has categorized these investments as available-for-sale securities, which are classified within "Investments" on the consolidated balance sheets. Available-for-sale securities are recorded at fair value each reporting period. Unrealized gains and losses, net of the related tax effects, are excluded from earnings and recorded as a separate component within "Accumulated other comprehensive income" on the consolidated balance sheets until realized. Interest income is reported within "Other expense, net" on the consolidated statements of operations.
Other-than-temporary Impairment for Investments [Policy Text Block]	Other-than-Temporary Impairment of Investments
	An unrealized loss exists when the current fair value of an investment is less than its amortized cost basis. The Company conducts reviews of its investments with unrealized losses on a quarterly basis to evaluate whether those impairments are other-than-temporary. This evaluation, which is performed at the individual investment level, consists of several qualitative and quantitative factors regarding the severity and duration of the unrealized loss as well as the Company's intent and ability to hold the investment for a period of time that is sufficient to allow for an anticipated recovery in value. Evidence considered in this evaluation includes the amount of the impairment, the length of time that the investment has been impaired, the factors contributing to the impairment, the financial condition and near-term prospects of the investee, recent operating trends and forecasted performance of the investee, market conditions in the geographic area or industry in which the investee operates, and the Company's strategic plans for holding the investment in relation to the period of time expected for an anticipated recovery in value. Additionally, the Company considers whether it intends to sell the investment or whether it is more-likely-than-not that the Company will be required to sell the investment before recovery of the amortized cost basis. Investments with unrealized losses that are determined to be other-than-temporary are written down to fair value with a charge to earnings. Unrealized losses that are determined to be temporary in nature are not recorded for cost method investments and equity method investments, while such losses are recorded, net of tax, in accumulated other comprehensive income for available-for-sale securities.
Income Tax, Policy [Policy Text Block]	Income Taxes
	The provision for income taxes is determined using the asset and liability method. Under this method, deferred tax assets and liabilities are calculated based upon the temporary differences between the financial statement and income tax bases of assets and liabilities using the enacted tax rates that are applicable in a given year. The deferred tax assets are recorded net of a valuation allowance when, based on the weight of available evidence, the Company believes it is more-likely-than-not that some portion or all of the recorded deferred tax assets will not be realized in future periods. The Company considers many factors when assessing the likelihood of future realization of its deferred tax assets, including recent cumulative earnings experience, expectations of future taxable income and capital gains by taxing jurisdiction, the carry‑forward periods available for tax reporting purposes, the ability to carryback losses and other relevant factors. The Company allocates its valuation allowance to current and non-current deferred tax assets on a pro-rata basis. A change in the estimate of future taxable income may require an increase or decrease to the valuation allowance.
	The Company utilizes a two-step approach to recognizing and measuring uncertain tax positions. The first step is to evaluate the tax position for recognition by determining if the weight of available evidence indicates it is more-likely-than-not that the position will be sustained on audit, including resolution of related appeals or litigation processes. The second step is to measure the tax benefit as the largest amount which is more than 50% likely of being realized upon ultimate settlement. The Company includes interest and penalties related to uncertain tax positions within "Provision for income taxes" on the consolidated statements of operations. See Note 12 "Income Taxes."
Lease, Policy [Policy Text Block]	Lease and Asset Retirement Obligations
	The Company categorizes leases at their inception as either operating or capital leases and may receive renewal or expansion options, rent holidays, and leasehold improvement and other incentives on certain lease agreements. The Company recognizes lease costs on a straight-line basis, taking into account adjustments for free or escalating rental payments and deferred payment terms. Additionally, lease incentives are accounted for as a reduction of lease costs over the term of the agreement. Leasehold improvements are capitalized at cost and amortized over the shorter of their useful life or the non-cancellable term of the lease. The Company records rent expense associated with operating lease obligations primarily within "Selling, general and administrative" on the consolidated statements of operations.
	The Company establishes assets and liabilities for the present value of estimated future costs to retire long-lived assets at the termination or expiration of a lease. Such assets are amortized over the lease term, and the recorded liabilities are accreted to the future value of the estimated retirement costs. The related amortization and accretion expenses are presented within "Selling, general and administrative" on the consolidated statements of operations.
Revenue Recognition, Policy [Policy Text Block]	Revenue Recognition
	The Company recognizes revenue when the following criteria are met: persuasive evidence of an arrangement exists; delivery has occurred; the selling price is fixed or determinable; and collection is reasonably assured.
	Third party revenue recognition
	The Company generates third party revenue, where it acts as a third party marketing agent, by offering goods and services provided by third party merchants at a discount through its online local commerce marketplaces that connect merchants to consumers. The Company's marketplaces include deals offered through a variety of categories including: Local, Goods and Travel. Customers purchase the discount vouchers ("Groupons") from the Company and redeem them with the Company's merchants.
	The revenue recognition criteria are met when the customer purchases a deal, the Groupon has been electronically delivered to the purchaser and a listing of Groupons sold has been made available to the merchant. At that time, the Company's obligations to the merchant, for which it is serving as a marketing agent, are substantially complete. The Company's remaining obligations, which are limited to remitting payment to the merchant and continuing to make available on the Company's website information about Groupons sold that was previously provided to the merchant, are inconsequential or perfunctory. For a portion of the hotel deals offered through the Company's online local marketplaces, the Company facilitates the booking of rooms by taking reservations through its websites. Such reservations are generally cancelable at any time prior to check-in and the Company defers the revenue on those deals until the customer's stay occurs.
	.    The Company records as revenue the net amount it retains from the sale of Groupons after deducting the portion of the purchase price that is payable to the featured merchant, excluding applicable taxes and net of estimated refunds for which the merchant's share is recoverable. Revenue is presented on a net basis because the Company is acting as a marketing agent of the merchant in the transaction.
	For merchant payment arrangements that are structured under a redemption model, merchants are not paid until the customer redeems the Groupon that has been purchased. If a customer does not redeem the Groupon under this payment model, the Company retains all the gross billings. The Company recognizes incremental revenue from unredeemed Groupons and derecognizes the related accrued merchant payable when its legal obligation to the merchant expires, which the Company believes is shortly after deal expiration in most jurisdictions that have payment arrangements structured under a redemption model.
	Direct revenue recognition
	The Company evaluates whether it is appropriate to record the gross amount of its sales and related costs by considering a number of factors, including, among other things, whether the Company is the primary obligor under the arrangement, has inventory risk and has latitude in establishing prices. Direct revenue is derived primarily from selling consumer products through the Company's Goods category where the Company is the merchant of record. The Company is the primary obligor in these transactions, is subject to general inventory risk and has latitude in establishing prices. Accordingly, direct revenue is presented on a gross basis, excluding applicable taxes and net of estimated refunds. Direct revenue, including associated shipping revenue, is recognized when title passes to the customer upon delivery of the product.
	Other revenue recognition
	Advertising revenue is recognized when the advertiser's logo or website link has been included on the Company's websites or in specified email distributions for the requisite period of time as set forth in the agreement with the advertiser. Commission revenue is earned when customers make purchases with retailers using coupons accessed through the Company's websites and mobile applications. Revenue from payment processing is earned on a per transaction basis. The Company recognizes revenue from those activities when the underlying transactions are completed. Revenue from point of sale solutions is recognized on a subscription basis over the term of the arrangement with the merchant.
	Discounts
	The Company provides discount offers to encourage purchases of goods and services through its marketplaces. The Company records discounts as a reduction of revenue.
Cost of Sales, Policy [Policy Text Block]	Cost of revenue
	Cost of revenue is comprised of direct and certain indirect costs incurred to generate revenue. For direct revenue transactions, cost of revenue includes the cost of inventory, shipping and fulfillment costs and inventory markdowns. Fulfillment costs are comprised of third party logistics provider costs, as well as rent, depreciation, personnel costs and other costs of operating the Company's fulfillment center, which began operations in the fourth quarter of 2013. For third party revenue transactions, cost of revenue includes estimated refunds for which the merchant's share is not recoverable. Other costs incurred to generate revenue, which include credit card processing fees, editorial costs, certain technology costs, web hosting and other processing fees, are allocated to cost of third party revenue, direct revenue and other revenue in proportion to gross billings during the period.
	Technology costs within cost of revenue consist of a portion of the payroll and stock‑based compensation expense related to the Company's technology support personnel who are responsible for operating and maintaining the infrastructure of the Company's websites. Technology costs also include a portion of amortization expense from internal-use software, primarily related to website development. Remaining technology costs within cost of revenue include email distribution costs. Editorial costs included in cost of revenue consist of payroll and stock‑based compensation expense related to the Company's editorial personnel, as these staff members are primarily dedicated to drafting and promoting deals.
Refunds Policy	Refunds
	The Company estimates future refunds utilizing a statistical model that incorporates the following data inputs and factors: historical refund experience developed from millions of deals featured on the Company's websites and mobile applications, the relative risk of refunds based on expiration date, deal value, deal category and other qualitative factors that could impact the level of future refunds, such as introductions of new deals, discontinuations of legacy deals and expected changes, if any, in Company practices in response to refund experience or economic trends that might impact customer demand. The portion of customer refunds for which the merchant's share is not recoverable on third party revenue deals is estimated based on the refunds that are expected to be issued after expiration of the related vouchers, the refunds that are expected to be issued due to the merchant bankruptcy or poor customer experience, and whether the payment terms of the related merchant contracts are structured using a redemption payment model or a fixed payment model.
	The Company accrues costs associated with refunds within "Accrued expenses" on the consolidated balance sheets. The cost of refunds for third party revenue where the amounts payable to the merchant are recoverable and for all direct revenue is presented on the consolidated statements of operations as a reduction to revenue. The cost of refunds for third party revenue for which the merchant's share is not recoverable is presented as a cost of revenue.
	The Company assesses the trends that could affect its estimates on an ongoing basis and makes adjustments to the refund reserve calculations if it appears that changes in circumstances, including changes to the Company's refund policies, may cause future refunds to differ from its original estimates. If actual results are not consistent with the estimates or assumptions stated above, the Company may need to change its future estimates, and the effects could be material to the consolidated financial statements.
Customer Credits Policy [Policy Text Block]	Customer Credits
	The Company issues credits to its customers that can be applied against future purchases through its online marketplaces for certain qualifying acts, such as referring new customers, and also to satisfy refund requests. The Company has recorded its customer credit obligations within "Accrued expenses" on the consolidated balance sheets (See Note 7 "Supplemental Consolidated Balance Sheet and Statements of Operations Information"). Customer credit obligations incurred for new customer referrals or other qualifying acts are expensed as incurred and are classified within "Marketing" on the consolidated statements of operations. Customer credits issued to satisfy refund requests are applied as a reduction to the refunds reserve.
Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]	Stock‑Based Compensation
	The Company measures stock‑based compensation cost at fair value, net of estimated forfeitures. Expense is generally recognized on a straight-line basis over the service period during which awards are expected to vest, except for awards with performance conditions, which are recognized using the accelerated method. The Company includes stock-based compensation expense within "Cost of revenue," "Marketing" and "Selling, general and administrative," consistent with the respective employees' cash compensation, on the consolidated statements of operations. See Note 11 "Compensation Arrangements."
Foreign Currency Transactions and Translations Policy [Policy Text Block]	Foreign Currency
	Balance sheet accounts of the Company's operations outside of the U.S. are translated from foreign currencies into U.S. dollars at the exchange rates as of the consolidated balance sheet dates. Revenue and expenses are translated at average exchange rates during the period. Foreign currency translation adjustments and foreign currency gains and losses on intercompany balances that are of a long-term investment nature are included within "Accumulated other comprehensive income" on the consolidated balance sheets. Foreign currency gains and losses resulting from transactions which are denominated in currencies other than the entity's functional currency, including foreign currency gains and losses on intercompany balances that are not of a long-term investment nature, are included within "Other expense, net" on the consolidated statements of operations. For the years ended December 31, 2014, 2013 and 2012, the Company had $31.5 million of foreign currency transaction losses, $10.3 million of foreign currency transaction losses and $1.4 million of foreign currency transaction gains, respectively.
Description of New Accounting Pronouncements Not yet Adopted [Text Block]	Recently Issued Accounting Standards
	In May 2014, the Financial Accounting Standards Board issued Accounting Standards Update ("ASU") 2014-09, Revenue from Contracts with Customers. This ASU is a comprehensive new revenue recognition model that requires a company to recognize revenue to depict the transfer of goods or services to a customer at an amount that reflects the consideration it expects to receive in exchange for those goods or services. The ASU is effective for annual periods beginning after December 15, 2016 and interim periods within those annual periods. The Company is still assessing the impact of adoption on its consolidated financial statements.
	There are no additional accounting standards that have been issued but not yet adopted that the Company believes will have a material impact on its consolidated financial position or results of operations.

Business_Combinations_and_Acqu1

Business Combinations and Acquisitions of Noncontrolling Interests (Tables)	12 Months Ended
	Dec. 31, 2014
Business Combinations [Abstract]
Schedule of Business Acquisitions, Consideration Transferred	The aggregate acquisition-date fair value of the consideration transferred for the Ticket Monster acquisition totaled $259.4 million, which consisted of the following (in thousands):
	Cash		$	96,496
	Issuance of 13,825,283 shares of Class A common stock		162,862
	Total		$	259,358
	The aggregate acquisition-date fair value of the consideration transferred for these acquisitions totaled $32.9 million, which consisted of the following (in thousands):
	Cash		$	17,364
	Issuance of 1,429,897 shares of Class A common stock		11,110
	Contingent consideration		4,388
	Total		$	32,862
	The fair value of the Class A Common Stock issued as consideration for one of the acquisitions was measured based on the stock price upon closing of the related transaction on November 13, 2014.
	The aggregate acquisition-date fair value of the consideration transferred for these acquisitions totaled $54.9 million, which consisted of the following (in thousands):
	Cash		$	49,013
	Purchase price obligations		2,485
	Contingent consideration		3,400
	Total		$	54,898
	The aggregate acquisition-date fair value of the consideration transferred for these acquisitions totaled $16.1 million, which consisted of the following (in thousands):
	Cash		$	9,459
	Issuance of Class A common stock		3,051
	Contingent consideration		3,567
	Total		$	16,077
Schedule of Business Acquisitions, Purchase Price Allocation	The following table summarizes the allocation of the aggregate acquisition price of the Ideel acquisition (in thousands):
	Cash and cash equivalents	$	79
	Accounts receivable	988
	Deferred income taxes	640
	Prepaid expenses and other current assets	22,081
	Property, equipment and software	8,173
	Goodwill	4,203
	Intangible assets:(1)
	Subscriber relationships	5,490
	Brand relationships	7,100
	Trade name	4,500
	Deferred income taxes, non-current	8,877
	Total assets acquired	$	62,131
	Accounts payable	$	1,640
	Accrued supplier payables	4,092
	Accrued expenses	9,118
	Other current liabilities	482
	Deferred income taxes, non-current	348
	Other non-current liabilities	3,753
	Total liabilities assumed	$	19,433
	Total acquisition price	$	42,698
	-1	The estimated useful lives of the acquired intangible assets are 3 years for subscriber relationships, 5 years for brand relationships and 5 years for trade name.
	The following table summarizes the allocation of the aggregate acquisition price of acquisitions for the year ended December 31, 2013 (in thousands):
	Net working capital (including acquired cash of $2.1 million)		$	1,728
	Property and equipment		99
	Goodwill		9,504
	Intangible assets: (1)
	Subscriber relationships		1,928
	Merchant relationships		757
	Developed technology		2,742
	Other intangible assets		50
	Net deferred tax liabilities		(731		)
	Total acquisition price		$	16,077
	-1	Acquired intangible assets have estimated useful lives of between 1 and 5 years.
	The following table summarizes the allocation of the aggregate acquisition price of the Ticket Monster acquisition (in thousands):
	Cash and cash equivalents	$	24,768
	Accounts receivable	17,732
	Deferred income taxes	1,264
	Prepaid expenses and other current assets	829
	Property, equipment and software	5,944
	Goodwill	218,692
	Intangible assets:(1)
	Subscriber relationships	57,022
	Merchant relationships	32,176
	Developed technology	571
	Trade name	19,325
	Other non-current assets	3,033
	Total assets acquired	$	381,356
	Accounts payable	$	5,951
	Accrued merchant and supplier payables	82,934
	Accrued expenses	22,700
	Other current liabilities	3,482
	Deferred income taxes, non-current	1,264
	Other non-current liabilities	5,667
	Total liabilities assumed	$	121,998
	Total acquisition price	$	259,358
	-1	The estimated useful lives of the acquired intangible assets are 5 years for subscriber relationships, 3 years for merchant relationships, 2 years for developed technology and 5 years for trade name.
	The following table summarizes the allocation of the aggregate purchase price of these other acquisitions (in thousands):
	Net working capital (including acquired cash of $0.2 million)		$	(396	)
	Goodwill		27,150
	Intangible assets: (1)
	Subscriber relationships		2,555
	Developed technology		3,372
	Brand relationships		579
Deferred income taxes, non-current		(398		)
Total purchase price		$	32,862
-1	Acquired intangible assets have estimated useful lives of between 1 and 5 years.
The following table summarizes the allocation of the aggregate acquisition price of acquisitions for the year ended December 31, 2012 (in thousands):
Net working capital (including acquired cash of $2.1 million)		$	1,750
Property and equipment		165
Goodwill		39,170
Intangible assets:(1)
Subscriber relationships		170
Merchant relationships		1,500
Developed technology		14,350
Net deferred tax liabilities		(2,207		)
Total acquisition price		$	54,898
-1	Acquired intangible assets have estimated useful lives of between 1 and 5 years.
Business Acquisition, Pro Forma Information [Table Text Block]	The following unaudited pro forma information presents the combined operating results of the Company for the year ended December 31, 2013, as if the Company had acquired Ticket Monster and Ideel as of January 1, 2013 (in thousands). Pro forma results of operations have not been presented for the year ended December 31, 2014, because the operating results of Ticket Monster and Ideel from January 1, 2014 through their respective acquisition dates were not material to the Company's consolidated results of operations for the year ended December 31, 2014. The underlying pro forma results include the historical financial results of the Company and these two acquired businesses adjusted for depreciation and amortization expense associated with the assets acquired. The unaudited pro forma results do not reflect any operating efficiencies or potential cost savings which may result from the consolidation of the operations of the Company and the acquired entities. Accordingly, these unaudited pro forma results are not necessarily indicative of what the actual results of operations of the combined company would have been if the acquisitions had occurred as of January 1, 2013, nor are they indicative of future results of operations.
		Year Ended
		December 31, 2013
	Revenue	$	2,763,639
	Net loss	(217,613		)

Property_Equipment_and_Softwar1

Property, Equipment and Software, Net Property, Equipment and Software (Tables)	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment [Table Text Block]	The following summarizes the Company's property, equipment and software, net (in thousands):
			December 31,
			2014			2013
	Warehouse equipment		$	4,859		$	3,997
	Furniture and fixtures		18,610			13,526
	Leasehold improvements		39,900			35,830
	Office and telephone equipment		4,448			5,062
	Purchased software		40,448			22,499
	Computer hardware(1)		135,731			84,673
	Internally-developed software		133,598			79,113
	Total property, equipment and software, gross		377,594			244,700
	Less: accumulated depreciation and amortization		(195,119		)	(110,277		)
	Property, equipment and software, net		$	182,475		$	134,423
	-1	Includes computer hardware acquired under capital leases of $48.0 million and $11.8 million as of December 31, 2014 and 2013, respectively.

Goodwill_and_Other_Intangible_1

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2014
GOODWILL AND OTHER INTANGIBLE ASSETS [Abstract]
Schedule of Goodwill [Table Text Block]	The following table summarizes the Company's goodwill activity by segment for the years ended December 31, 2014 and 2013 (in thousands):
			North America			International			EMEA			Rest of World			Consolidated
	Balance as of December 31, 2012		$	79,276		$	127,408		$	—		$	—		$	206,684
	Reallocation to new segments		—			(124,770		)	105,347			19,423			—
	Goodwill related to acquisitions		4,893			—			4,611			—			9,504
	Other adjustments(1)		1,288			(2,638		)	5,711			278			4,639
	Balance as of December 31, 2013		$	85,457		$	—		$	115,669		$	19,701		$	220,827
	Goodwill related to acquisitions		31,353			—			—			218,692			250,045
	Other adjustments(1)		(92		)	—			(13,490		)	(9,480		)	(23,062		)
	Balance as of December 31, 2014		$	116,718		$	—		$	102,179		$	228,913		$	447,810
	-1	Represents the impact of changes in foreign exchange rates on goodwill.
Schedule of Finite-Lived Intangible Assets by Major Class [Table Text Block]	The following tables summarize the Company's intangible assets (in thousands):
			31-Dec-14
	Asset Category		Gross Carrying Value			Accumulated Amortization			Net Carrying Value
	Subscriber relationships		$	103,858		$	48,754		$	55,104
	Merchant relationships		39,448			18,677			20,771
	Trade names		29,190			10,666			18,524
	Developed technology		25,903			21,989			3,914
	Brand relationships		7,664			1,486			6,178
	Other intangible assets		17,045			10,979			6,066
	Total		$	223,108		$	112,551		$	110,557
			31-Dec-13
	Asset Category		Gross Carrying Value			Accumulated Amortization			Net Carrying Value
	Subscriber relationships		$	45,541		$	30,866		$	14,675
	Merchant relationships		9,186			7,991			1,195
	Trade names		6,739			6,739			—
	Developed technology		23,038			19,547			3,491
	Other intangible assets		16,776			7,694			9,082
	Total		$	101,280		$	72,837		$	28,443
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]	As of December 31, 2014, the Company's estimated future amortization expense related to intangible assets is as follows (in thousands):
	Years Ended December 31,
	2015		$	40,495
	2016		33,707
	2017		18,653
	2018		17,617
	2019		85
	Thereafter		—
	Total		$	110,557

Investments_Tables

Investments (Tables)	12 Months Ended
	Dec. 31, 2014
Investments, All Other Investments [Abstract]
Schedule of Cost and Equity Method Investments [Table Text Block]	The following table summarizes the Company's investments (dollars in thousands):
		31-Dec-14		Percent Ownership of Voting Stock						December 31, 2013				Percent Ownership of Voting Stock
	Cost and equity method investments:
	Cost method investments	$	15,630	6	%	to	19	%		$	15,788			6	%	to	19	%
	Equity method investments	1,231		21	%	to	50	%		1,690				21	%	to	50	%
	Total cost and equity method investments	16,861								17,478
	Available-for-sale securities:
	Convertible debt securities	2,527								3,174
	Redeemable preferred shares	4,910		17	%	to	19	%		—				19	%
	Total available-for-sale securities	7,437								3,174
	Total investments	$	24,298							$	20,652
Schedule of Available-for-sale Securities Reconciliation [Table Text Block]	The following table summarizes the amortized cost, gross unrealized gain, gross unrealized loss and fair value of the Company's available-for-sale securities as of December 31, 2014 and 2013, respectively (in thousands):
		31-Dec-14														December 31, 2013
		Amortized Cost		Gross Unrealized Gain				Gross Unrealized Loss				Fair Value				Amortized Cost			Gross Unrealized Gain		Gross Unrealized Loss			Fair Value
	Available-for-sale securities:
	Convertible debt securities	$	2,030	$	497			$	—			$	2,527			$	3,370		$	—	$	(196	)	$	3,174
	Redeemable preferred shares	4,599		311				—				4,910				—			—		—			—
	Total available-for-sale securities	$	6,629	$	808			$	—			$	7,437			$	3,370		$	—	$	(196	)	$	3,174

Supplemental_Consolidated_Bala1

Supplemental Consolidated Balance Sheet and Statement of Operations Information (Tables)	12 Months Ended
	Dec. 31, 2014
SUPPLEMENTAL CONSOLIDATED BALANCE SHEET AND STATEMENT OF OPERATIONS INFORMATION [Abstract]
Schedule of Other Income (Expense) [Table Text Block]	The following table summarizes the Company's other expense, net for the years ended December 31, 2014, 2013 and 2012 (in thousands):
			Year Ended December 31,
			2014				2013				2012
	Interest income		$	1,564			$	1,721			$	2,522
	Interest expense		(907		)		(291		)		—
	Gain on E-Commerce transaction		—				—				56,032
	Impairments of investments		(2,036		)		(85,925		)		(50,553		)
	Loss on equity method investments		(459		)		(44		)		(9,925		)
	Foreign exchange (losses) gains, net		(31,526		)		(10,271		)		1,403
	Other		11				147				(3,238		)
	Other expense, net		$	(33,353	)		$	(94,663	)		$	(3,759	)
Schedule of Prepaid Expenses and Other Current Assets [Table Text Block]	The following table summarizes the Company's prepaid expenses and other current assets as of December 31, 2014 and 2013 (in thousands):
		December 31,
		2014				2013
	Current portion of unamortized tax effects on intercompany transactions	$	14,193			$	28,502
	Finished goods inventories	57,134				57,097
	Prepaid expenses	42,231				29,404
	Restricted cash	12,019				14,579
	Income taxes receivable	41,788				39,994
	VAT receivable	17,746				12,966
	Prepaid marketing	7,443				17,301
	Other	15,437				10,572
	Total prepaid expenses and other current assets	$	207,991			$	210,415
Schedule of Accrued Merchant and Supplier Payables [Table Text Block]	The following table summarizes the Company's accrued merchant and supplier payables as of December 31, 2014 and 2013 (in thousands):
		December 31,
		2014				2013
	Accrued merchant payables	$	632,605			$	518,233
	Accrued supplier payables(1)	277,962				234,710
	Total accrued merchant and supplier payables	$	910,567			$	752,943
	-1	Amounts include payables to suppliers of inventories and providers of shipping and fulfillment services.
Schedule of Accrued Expenses [Table Text Block]	The following table summarizes the Company's accrued expenses as of December 31, 2014 and 2013 (in thousands):
		December 31,
		2014				2013
	Marketing	$	15,962			$	12,001
	Refunds reserve	33,238				38,597
	Payroll and benefits	65,743				64,966
	Customer credits	44,463				44,728
	Professional fees	14,292				18,906
	Other	56,654				47,788
	Total accrued expenses	$	230,352			$	226,986
Schedule of Other Current Liabilities [Table Text Block]	The following table summarizes the Company's other current liabilities as of December 31, 2014 and 2013 (in thousands):
		December 31,
		2014				2013
	Income taxes payable	$	14,461			$	21,994
	VAT payable	33,436				37,627
	Sales taxes payable	9,042				10,412
	Deferred revenue	43,903				47,259
	Capital lease obligations	14,872				3,636
	Other	14,598				11,790
	Total other current liabilities	$	130,312			$	132,718
Schedule of Other Liabilities, Noncurrent [Table Text Block]	The following table summarizes the Company's other non-current liabilities as of December 31, 2014 and 2013 (in thousands):
		December 31,
		2014				2013
	Long-term tax liabilities	$	82,138			$	109,286
	Deferred rent	13,200				9,148
	Capital lease obligations	23,387				5,665
	Other	17,559				7,598
	Total other non-current liabilities	$	136,284			$	131,697
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	The following table summarizes the components of accumulated other comprehensive income, net of tax, as of December 31, 2014, 2013 and 2012 (in thousands):
		Foreign currency translation adjustments				Unrealized loss on available-for-sale securities				Pension liability adjustment				Total
	Balance as of December 31, 2012	$	12,393			$	53			$	—			$	12,446
	Other comprehensive income	12,559				(175		)		—				12,384
	Balance as of December 31, 2013	24,952				(122		)		—				24,830
	Other comprehensive income (loss) before reclassification adjustments	11,812				(210		)		(1,500		)		10,102
	Reclassification adjustment for impairment included in net loss	—				831				—				831
	Other comprehensive income (loss)	11,812				621				(1,500		)		10,933
	Balance as of December 31, 2014	$	36,764			$	499			$	(1,500	)		$	35,763
	The effects of amounts reclassified from accumulated other comprehensive income to net loss for the years ended December 31, 2014, 2013 and 2012 are presented within the following line items in the consolidated statements of operations (in thousands):
			Year Ended December 31,												Consolidated Statements of Operations Line Item
			2014				2013				2012
	Other-than-temporary impairment of available-for-sale security		$	1,340			$	—			$	—			Other expense, net
	Less: Tax effect		(509		)		—				—				Provision for income taxes
	Reclassification adjustment		$	831			$	—			$	—

Commitments_and_Contingencies_

Commitments and Contingencies Operating Leases (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	As of December 31, 2014, the estimated future payments under operating leases and capital leases for each of the next five years and thereafter is as follows (in thousands):
		Capital Leases			Operating leases
	2015	$	14,936		$	53,776
	2016	14,136			49,094
	2017	9,424			38,628
	2018	697			27,659
	2019	522			11,455
	Thereafter	—			21,514
	Total minimum lease payments	39,715			$	202,126
	Less: Amount representing interest	(1,456		)
	Present value of net minimum capital lease payments	38,259
	Less: Current portion of capital lease obligations	(14,872		)
	Total long-term capital lease obligations	$	23,387

Commitments_and_Contingencies_1

Commitments and Contingencies Purchase Obligations (Tables)	12 Months Ended
	Dec. 31, 2014
Long-term Purchase Commitment [Line Items]
Long-term Purchase Commitment [Table Text Block]	The Company has entered into non-cancelable arrangements with third-parties, primarily related to information technology products and services. As of December 31, 2014, future payments under these contractual obligations were as follows (in thousands):
	2015	$	33,636
	2016	21,922
	2017	5,730
	2018	8
	2019	4
	Thereafter	—
	Total purchase obligations	$	61,300

Compensation_Arrangements_Tabl

Compensation Arrangements (Tables)	12 Months Ended
	Dec. 31, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]	The table below summarizes the stock option activity for the year ended December 31, 2014:
			Options		Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value
								(in thousands) (1)
	Outstanding at December 31, 2013		3,355,054		$	1.11	6.04	$	35,742
	Exercised		(1,029,471	)	$	1.09
	Forfeited		(62,589	)	$	2.41
	Outstanding at December 31, 2014		2,262,994		$	1.09	5.03	$	16,226
	Exercisable at December 31, 2014		2,262,994		$	1.09	5.03	$	16,226
	-1	The aggregate intrinsic value of options outstanding and exercisable represents the total pretax intrinsic value (the difference between the fair value of the Company's stock on the last day of each period and the exercise price, multiplied by the number of options where the fair value exceeds the exercise price) that would have been received by the option holders had all option holders exercised their options as of December 31, 2014 and 2013, respectively.

Compensation_Arrangements_Comp

Compensation Arrangements Compensation Arrangements Restricted Stock Activity (Tables)	12 Months Ended
	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block]	The table below summarizes activity regarding unvested restricted stock units under the Plans for the year ended December 31, 2014:
		Restricted Stock Units		Weighted- Average Grant Date Fair Value (per share)
	Unvested at December 31, 2013	41,648,055		$	8.06
	Granted	29,568,490		$	7.59
	Vested	(17,323,096	)	$	8.07
	Forfeited	(12,555,522	)	$	7.96
	Unvested at December 31, 2014	41,337,927		$	7.78

Compensation_Arrangements_Comp1

Compensation Arrangements Compensation Arrangements Performance Share Units (Tables)	12 Months Ended
	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of Nonvested Performance-based Units Activity [Table Text Block]	The table below summarizes activity regarding unvested performance share units for the year ended December 31, 2014:
		Performance Share Units		Weighted- Average Grant Date Fair Value (per share)
	Unvested at December 31, 2013	—		$	—
	Granted	1,983,232		$	8.07
	Vested	—		$	—
	Forfeited	(967,388	)	$	8.07
	Unvested at December 31, 2014	1,015,844		$	8.07

Compensation_Arrangements_Comp2

Compensation Arrangements Compensation Arrangements Restricted Stock Awards (Tables)	12 Months Ended
	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of Share-based Compensation, Restricted Stock Units Award Activity [Table Text Block]	The table below summarizes activity regarding unvested restricted stock for the year ended December 31, 2014:
		Restricted Stock Awards		Weighted- Average Grant Date Fair Value (per share)
	Unvested at December 31, 2013	97,677		$	14
	Granted	—		$	—
	Vested	(50,481	)	$	14.54
	Forfeited	(13,129	)	$	17.07
	Unvested at December 31, 2014	34,067		$	15.53

Income_Taxes_Income_Taxes_Tabl

Income Taxes Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]	The components of pretax (loss) income for the years ended December 31, 2014, 2013 and 2012 were as follows (in thousands):
		Year Ended December 31,
		2014				2013				2012
	United States	$	(20,057	)		$	62,021			$	88,638
	International	(28,138		)		(80,930		)		6,304
	(Loss) income before provision for income taxes	$	(48,195	)		$	(18,909	)		$	94,942
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]	The provision for income taxes for the years ended December 31, 2014, 2013 and 2012 consisted of the following components (in thousands):
		Year Ended December 31,
		2014				2013				2012
	Current taxes:
	U.S. federal	$	(3,518	)		$	22,321			$	41,551
	State	69				1,693				4,778
	International	30,279				64,078				107,295
	Total current taxes	26,830				88,092				153,624
	Deferred taxes:
	U.S. federal	(5,132		)		4,675				(2,977		)
	State	(742		)		(5,687		)		(236		)
	International	(5,232		)		(17,043		)		(4,438		)
	Total deferred taxes	(11,106		)		(18,055		)		(7,651		)
	Provision for income taxes	$	15,724			$	70,037			$	145,973
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	The items accounting for differences between the income tax provision or benefit computed at the federal statutory rate and the provision for income taxes for the years ended December 31, 2014, 2013 and 2012 were as follows:
		Year Ended December 31,
		2014				2013				2012
	U.S. federal income tax (benefit) provision at statutory rate	$	(16,868	)		$	(6,618	)		$	33,230
	Foreign income and losses taxed at different rates	4,815				14,299				10,565
	Unrecognized tax benefits on E-Commerce transaction	—				—				17,404
	State income taxes, net of federal benefits and state tax credits	(10,051		)		(5,361		)		3,965
	Change in valuation allowances	23,515				24,404				29,249
	Effect of foreign and state rate changes on deferred items	178				837				(487		)
	Tax effects of intercompany transactions(1)	13,098				35,158				31,011
	Non-deductible stock-based compensation expense	6,503				9,000				14,641
	Federal research and development credits	(4,693		)		(4,650		)		—
	Non-deductible or non-taxable items	(773		)		2,968				6,395
	Provision for income taxes	$	15,724			$	70,037			$	145,973
	-1	Includes a tax benefit of $24.4 million for the year ended December 31, 2014 resulting from decreases in the Company's liabilities for uncertain tax positions.
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	The deferred income tax assets and liabilities consisted of the following components as of December 31, 2014 and 2013 (in thousands):
		December 31,
		2014				2013
	Deferred tax assets:
	Reserves and allowances	$	32,379			$	65,356
	Stock-based compensation	6,911				13,462
	Net operating loss and tax credit carryforwards	221,674				152,271
	Intangible assets, net	11,910				30,039
	Investments	1,441				3,730
	Unrealized foreign exchange losses	5,011				—
	Other	2,610				1,692
	Total deferred tax assets	281,936				266,550
	Less valuation allowances	(205,486		)		(173,577		)
	Deferred tax assets, net of valuation allowance	76,450				92,973
	Deferred tax liabilities:
	Unrealized foreign exchange gains	—				(3,034		)
	Prepaid expenses and other assets	(1,455		)		(1,078		)
	Property, equipment and software, net	(25,159		)		(19,239		)
	Deferred revenue	(25,013		)		(64,154		)
	Total deferred tax liabilities	(51,627		)		(87,505		)
	Net deferred tax asset	$	24,823			$	5,468
Summary of Income Tax Contingencies [Table Text Block]	The following table summarizes activity related to the Company's gross unrecognized tax benefits, excluding interest and penalties, from January 1 to December 31, 2014, 2013 and 2012 (in thousands):
			Year Ended December 31,
			2014				2013				2012
	Beginning Balance		$	110,305			$	85,481			$	55,127
	Increases related to prior year tax positions		5,489				10,494				602
	Decreases related to prior year tax positions		(27,875		)		(2,103		)		(790		)
	Increases related to current year tax positions		17,348				14,565				29,465
	Foreign currency translation		(6,946		)		1,868				1,077
	Ending Balance		$	98,321			$	110,305			$	85,481

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2014
FAIR VALUE MEASUREMENTS [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]	The following tables summarize the Company's assets and liabilities that are measured at fair value on a recurring basis (in thousands):
						Fair Value Measurement at Reporting Date Using
	Description	31-Dec-14				Quoted Prices in Active Markets for				Significant Other				Significant
						Identical Assets				Observable				Unobservable
						(Level 1)				Inputs				Inputs
										(Level 2)				(Level 3)
	Assets:
	Cash equivalents	$	440,596			$	440,596			$	—			$	—
	Available-for-sale securities:
	Convertible debt securities	2,527				—				—				2,527
	Redeemable preferred shares	4,910				—				—				4,910
	Liabilities:
	Contingent consideration	1,983				—				—				1,983
						Fair Value Measurement at Reporting Date Using
	Description	31-Dec-13				Quoted Prices in Active Markets for				Significant Other				Significant
						Identical Assets				Observable				Unobservable
						(Level 1)				Inputs				Inputs
										(Level 2)				(Level 3)
	Assets:
	Cash equivalents	$	585,514			$	585,514			$	—			$	—
	Available-for-sale securities:
	Convertible debt securities	3,174				—				—				3,174
	Redeemable preferred shares	—				—				—				—
	Liabilities:
	Contingent consideration	606				—				—				606
Fair Value, Assets and Liabilities, Reconciliation of Level 3 Inputs [Table Text Block]
						Fair Value Measurement at Reporting Date Using
	Description	31-Dec-13				Quoted Prices in Active Markets for				Significant Other				Significant
						Identical Assets				Observable				Unobservable
						(Level 1)				Inputs				Inputs
										(Level 2)				(Level 3)
	Assets:
	Cash equivalents	$	585,514			$	585,514			$	—			$	—
	Available-for-sale securities:
	Convertible debt securities	3,174				—				—				3,174
	Redeemable preferred shares	—				—				—				—
	Liabilities:
	Contingent consideration	606				—				—				606
	The following table provides a roll-forward of the fair value of recurring Level 3 fair value measurements for the years ended December 31, 2014, 2013 and 2012 (in thousands):
			Year Ended December 31,
			2014				2013				2012
	Assets
	Available-for-sale securities
	Convertible debt securities:
	Beginning Balance		$	3,174			$	3,087			$	—
	Purchases of convertible debt securities		—				370				3,000
	Total gains (losses) included in other comprehensive income		693				(283		)		87
	Total gains (losses) included in other expense, net		(1,340		)		—				—
	Ending Balance		$	2,527			$	3,174			$	3,087
	Unrealized (losses) gains still held(1)		$	(647	)		$	(283	)		$	87
	Redeemable preferred shares:
	Beginning Balance		$	—			$	42,539			$	—
	Acquisitions of preferred shares in exchange transactions (See note 6)		—				34,982				56,940
	Purchase of redeemable preferred shares		4,599				8,000				—
	Total gains included in other comprehensive income		311				—				—
	Other-than-temporary impairments included in earnings		—				(85,521		)		(14,401		)
	Ending Balance		$	4,910			$	—			$	42,539
	Unrealized (losses) gains still held(1)		$	311			$	(85,521	)		$	(14,401	)
	Liabilities
	Contingent Consideration:
	Beginning Balance		$	606			$	7,601			$	11,230
	Issuance of contingent consideration in connection with acquisitions		4,388				3,567				3,400
	Settlements of contingent consideration liabilities		(424		)		(4,377		)		(4,936		)
	Reclass to non-fair value liabilities when no longer contingent		(143		)		(3,014		)		(4,978		)
	Total (gains) losses included in earnings(2)		(2,444		)		(3,171		)		897
	Reclass of contingent consideration from Level 2 to Level 3		—				—				1,988
	Ending Balance		$	1,983			$	606			$	7,601
	Unrealized (gains) losses still held(1)		$	(2,405	)		$	360			$	211
	-1	Represents the unrealized losses or gains recorded in earnings and/or other comprehensive income (loss) during the period for assets and liabilities classified as Level 3 that are still held (or outstanding) at the end of the period.
	-2	Changes in the fair value of contingent consideration liabilities are classified within "Acquisition-related expense (benefit), net" on the consolidated statements of operations.
Fair Value Measurements, Nonrecurring [Table Text Block]	The following table summarizes the Company's assets that were measured at fair value on a nonrecurring basis as of December 31, 2012 (in thousands):
						Fair Value Measurement at Reporting Date Using
	Description	31-Dec-12				Quoted Prices				Significant				Significant
						in Active				Other				Unobservable
						Markets for				Observable				Inputs
						Identical				Inputs				(Level 3)
						Assets				(Level 2)
						(Level 1)
	Asset impairments:
	Cost method investment in Life Media Limited (F-tuan) common shares	$	34,982			$	—			$	—			$	34,982
	Equity method investment	$	495			$	—			$	—			$	495
Fair Value of Financial Assets and Liabilities not Measured at Fair Value [Table Text Block]	The following table presents the carrying amounts and fair values of financial instruments that are not carried at fair value in the consolidated financial statements (in thousands):
			31-Dec-14								31-Dec-13
			Carrying Amount				Fair Value				Carrying Amount				Fair Value
	Cost method investments		$	15,630			$	16,134			$	15,788			$	15,573

Loss_Per_Share_of_Class_A_and_1

Loss Per Share of Class A and Class B Common Stock (Tables)	12 Months Ended
	Dec. 31, 2014
LOSS PER SHARE OF CLASS A AND CLASS B COMMON STOCK [Abstract] [Abstract]
Schedule of Earnings per Share, Basic and Diluted [Table Text Block]	The following table sets forth the computation of basic and diluted loss per share of Class A and Class B common stock for the years ended December 31, 2014, 2013 and 2012 (in thousands, except share amounts and per share amounts):
			Year Ended December 31,
			2014							2013						2012
			Class A				Class B			Class A			Class B			Class A			Class B
	Basic loss per share:
	Numerator
	Allocation of net loss		$	(63,691	)		$	(228	)	$	(88,626	)	$	(320	)	$	(50,842	)	$	(189	)
	Less: Allocation of adjustment of redeemable noncontrolling interests to redemption value		—				—			—			—			12,557			47
	Less: Allocation of net income attributable to noncontrolling interests		9,138				33			6,424			23			3,728			14
	Allocation of net loss attributable to common stockholders		$	(72,829	)		$	(261	)	$	(95,050	)	$	(343	)	$	(67,127	)	$	(250	)
	Denominator
	Weighted-average common shares outstanding		672,432,417				2,399,976			661,510,218			2,399,976			647,814,143			2,399,976
	Basic loss per share		$	(0.11	)		$	(0.11	)	$	(0.14	)	$	(0.14	)	$	(0.10	)	$	(0.10	)
	Diluted loss per share:
	Numerator
	Allocation of net loss attributable to common stockholders		$	(72,829	)		$	(261	)	$	(95,050	)	$	(343	)	$	(67,127	)	$	(250	)
	Reallocation of net income attributable to common stockholders as a result of conversion of Class B(1)		—				—			—			—			—			—
	Allocation of net loss attributable to common stockholders		$	(72,829	)		$	(261	)	$	(95,050	)	$	(343	)	$	(67,127	)	$	(250	)
	Denominator
	Weighted-average common shares outstanding used in basic computation		672,432,417				2,399,976			661,510,218			2,399,976			647,814,143			2,399,976
	Conversion of Class B(1)		—				—			—			—			—			—
	Employee stock options(1)		—				—			—			—			—			—
	Restricted shares and RSUs(1)		—				—			—			—			—			—
	Weighted-average diluted shares outstanding(1)		672,432,417				2,399,976			661,510,218			2,399,976			647,814,143			2,399,976
	Diluted loss per share		$	(0.11	)		$	(0.11	)	$	(0.14	)	$	(0.14	)	$	(0.10	)	$	(0.10	)
	-1	Conversion of Class B shares into Class A shares and outstanding equity awards have not been reflected in the diluted loss per share calculation for the years ended December 31, 2014, 2013 and 2012 because the effect would be antidilutive.
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]	The following outstanding equity awards are not included in the diluted loss per share calculation above because they would have had an antidilutive effect:
			Year Ended December 31,
			2014			2013			2012
	Stock options		2,775,771			5,594,033			7,713,421
	Restricted stock units		42,341,320			39,618,897			29,699,348
	Restricted stock		52,854			298,292			577,048
	ESPP shares		507,916			444,439			271,402
	Total		45,677,861			45,955,661			38,261,219

Segment_Information_Tables

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2014
SEGMENT INFORMATION [Abstract]
Schedule of Segment Reporting Information, by Segment [Table Text Block]	Revenue and profit or loss information by reportable segment reconciled to consolidated net loss for the years ended December 31, 2014, 2013 and 2012 were as follows (in thousands):
			Year Ended December 31,
			2014				2013				2012
	North America
	Revenue(1)		$	1,824,461			$	1,521,358			$	1,165,700
	Segment cost of revenue and operating expenses(2)		1,755,113				1,380,746				1,025,974
	Segment operating income(2)		69,348				140,612				139,726
	EMEA
	Revenue(1)		961,130				742,915				805,476
	Segment cost of revenue and operating expenses(2)		857,062				631,409				699,470
	Segment operating income(2)		104,068				111,506				106,006
	Rest of World
	Revenue		406,097				309,382				363,296
	Segment cost of revenue and operating expenses(2)		471,067				364,295				405,313
	Segment operating loss(2)		(64,970		)		(54,913		)		(42,017		)
	Consolidated
	Revenue		3,191,688				2,573,655				2,334,472
	Segment cost of revenue and operating expenses(2)		3,083,242				2,376,450				2,130,757
	Segment operating income(2)		108,446				197,205				203,715
	Stock-based compensation		122,019				121,462				104,117
	Acquisition-related expense (benefit), net		1,269				(11		)		897
	(Loss) income from operations		(14,842		)		75,754				98,701
	Other expense, net		(33,353		)		(94,663		)		(3,759		)
	(Loss) income before provision for income taxes		(48,195		)		(18,909		)		94,942
	Provision for income taxes		15,724				70,037				145,973
	Net loss		$	(63,919	)		$	(88,946	)		$	(51,031	)
	-1	North America includes revenue from the United States of $1,784.6 million, $1,471.9 million and $1,108.4 million for the years ended December 31, 2014, 2013 and 2012 respectively. Beginning in September 2013, direct revenue transactions in the EMEA Goods category have been transacted through a Switzerland-based subsidiary. As a result, EMEA includes revenue from Switzerland of $468.7 million for the year ended December 31, 2014. There were no other individual countries that represented more than 10% of consolidated total revenue for the years ended December 31, 2014, 2013 or 2012.
	-2	Segment cost of revenue and operating expenses and segment operating income (loss) exclude stock-based compensation and acquisition-related (benefit) expense, net. This presentation corresponds to the measure of segment profit or loss that the Company's chief operating decision-maker uses in assessing segment performance and making resource allocation decisions. The following table summarizes the Company's stock-based compensation expense and acquisition-related expense (benefit), net by reportable segment for the years ended December 31, 2014, 2013 and 2012. (in thousands):
Stock Based Compensation and Acquisition Related by Segment [Table Text Block]	The following table summarizes the Company's stock-based compensation expense and acquisition-related expense (benefit), net by reportable segment for the years ended December 31, 2014, 2013 and 2012. (in thousands):
			Year Ended December 31,
			2014								2013								2012
			Stock-based compensation				Acquisition-related				Stock-based compensation				Acquisition-related				Stock-based compensation			Acquisition-related
	North America		$	99,939			$	1,125			$	90,877			$	1,285			$	65,127		$	(2,780	)
	EMEA		9,927				144				16,263				(1,296		)		15,123			3,677
	Rest of World		12,153				—				14,322				—				23,867			—
	Consolidated		$	122,019			$	1,269			$	121,462			$	(11	)		$	104,117		$	897
	Acquisition-related expense (benefit), net for the North America segment includes external transaction costs and gains and losses relating to contingent consideration obligations incurred by U.S. legal entities relating to purchases of businesses that became part of the EMEA and Rest of World segments, which is consistent with the attribution used for internal reporting purposes.
Schedule of Segment Assets [Table Text Block]	The following table summarizes the Company's total assets by reportable segment as of December 31, 2014 and 2013 (in thousands):
		December 31,
		2014				2013
	North America (1)	$	1,150,417			$	1,267,158
	EMEA	552,486				616,126
	Rest of World (1)	524,694				158,726
	Consolidated total assets	$	2,227,597			$	2,042,010
	-1	North America contains assets from the United States of $1,120.4 million and $1,231.3 million as of December 31, 2014 and 2013, respectively. Rest of World contains assets from the Republic of Korea, including those assets acquired as a part of our acquisition of Ticket Monster described in Note 3 "Business Combinations," of $388.0 million as of December 31, 2014. There were no other individual countries that represented more than 10% of consolidated total assets as of December 31, 2014 and 2013, respectively.
Schedule of Long-lived Assets by Segment[Table Text Block]	The following table summarizes the Company's tangible property and equipment, net of accumulated depreciation and amortization, by reportable segment as of December 31, 2014 and 2013 (in thousands):
		December 31,
		2014				2013
	North America (1)	$	63,915			$	43,126
	EMEA (2)	28,721				23,413
	Rest of World	11,167				9,100
	Consolidated total	$	103,803			$	75,639
	-1	Substantially all tangible property and equipment within North America is located in the United States.
	-2	Tangible property and equipment, net located within Ireland represented approximately 12% of the Company's consolidated tangible property and equipment, net as of December 31, 2014. Tangible property and equipment, net located within Switzerland represented approximately 11% of the Company's consolidated tangible property and equipment, net as of December 31, 2013. There were no other individual countries located outside of the United States that represented more than 10% of consolidated tangible property and equipment, net as of December 31, 2014 and 2013.
Property, Plant and Equipment and Intangible Asset Depreciation and Amortization [Table Text Block]	The following table summarizes depreciation and amortization of property, equipment and software and intangible assets by reportable segment for the years ended December 31, 2014, 2013 and 2012 (in thousands):
		Year Ended December 31,
		2014				2013				2012
	North America	$	83,106			$	57,700			$	30,580
	EMEA	24,849				24,157				17,546
	Rest of World	36,966				7,592				7,675
	Consolidated total	$	144,921			$	89,449			$	55,801
Schedule of capital expenditures [Table Text Block]	The following table summarizes the Company's expenditures for additions to tangible long-lived assets by reportable segment for the years ended December 31, 2014, 2013 and 2012 (in thousands):
		Year Ended December 31,
		2014				2013				2012
	North America	$	6,775			$	14,728			$	38,543
	EMEA	12,945				6,719				26,909
	Rest of World	11,616				7,469				3,875
	Consolidated total	$	31,336			$	28,916			$	69,327
Revenue by Segment and Category [Table Text Block]	The following table summarizes the Company's third party and other and direct revenue by category for its three reportable segments for the years ended December 31, 2014, 2013 and 2012 (in thousands):
		North America												EMEA											Rest of World									Consolidated
		Year Ended												Year Ended											Year Ended									Year Ended
		December 31,												December 31,											December 31,									December 31,
		2014				2013				2012				2014				2013			2012				2014			2013			2012			2014		2013			2012
	Local (1):
	Third party and other	$	674,605			$	671,846			$	665,587			$	391,179			$	430,020		$	501,782			$	167,552		$	182,010		$	221,859		$	1,233,336	$	1,283,876		$	1,389,228
	Direct	—				1,772				12,037				—				—			—				—			—			—			—		1,772			12,037
	Total	674,605				673,618				677,624				391,179				430,020			501,782				167,552			182,010			221,859			1,233,336		1,285,648			1,401,265
	Goods:
	Third party	5,966				17,409				60,269				63,650				133,117			186,495				146,984			69,344			87,746			216,600		219,870			334,510
	Direct	1,074,913				774,023				391,239				442,344				115,881			36,393				46,892			27,325			10,821			1,564,149		917,229			438,453
	Total	1,080,879				791,432				451,508				505,994				248,998			222,888				193,876			96,669			98,567			1,780,749		1,137,099			772,963
	Travel:
	Third party	68,977				56,308				36,568				63,957				63,897			76,553				44,669			30,703			42,870			177,603		150,908			155,991
	Direct	—				—				—				—				—			4,253				—			—			—			—		—			4,253
	Total	68,977				56,308				36,568				63,957				63,897			80,806				44,669			30,703			42,870			177,603		150,908			160,244
	Total revenue	$	1,824,461			$	1,521,358			$	1,165,700			$	961,130			$	742,915		$	805,476			$	406,097		$	309,382		$	363,296		$	3,191,688	$	2,573,655		$	2,334,472
	-1	Includes revenue from deals with local and national merchants and through local events.
Gross Profit by Segment and Category [Table Text Block]	The following table summarizes the Company's gross profit by category for its three reportable segments for the years ended December 31, 2014, 2013 and 2012 (in thousands):
		North America												EMEA											Rest of World									Consolidated
		Year Ended												Year Ended											Year Ended									Year Ended
		December 31,												December 31,											December 31,									December 31,
		2014				2013				2012				2014				2013			2012				2014			2013			2012			2014		2013			2012
	Local (1):
	Third party and other	$	581,067			$	582,723			$	541,716			$	364,545			$	383,725		$	453,970			$	138,527		$	153,406		$	173,735		$	1,084,139	$	1,119,854		$	1,169,421
	Direct	—				(782		)		1,909				—				—			—				—			—			—			—		(782		)	1,909
	Total	581,067				581,941				543,625				364,545				383,725			453,970				138,527			153,406			173,735			1,084,139		1,119,072			1,171,330
	Goods:
	Third party	5,112				15,319				48,288				55,434				116,357			168,429				91,486			39,699			66,271			152,032		171,375			282,988
	Direct	88,810				66,753				36,188				77,706				13,194			(2,521		)		(2,984		)	(224		)	(2,563		)	163,532		79,723			31,104
	Total	93,922				82,072				84,476				133,140				129,551			165,908				88,502			39,475			63,708			315,564		251,098			314,092
	Travel:
	Third party	56,994				48,824				27,208				59,229				56,850			68,777				33,260			25,689			33,596			149,483		131,363			129,581
	Direct	—				—				—				—				—			529				—			—			—			—		—			529
	Total	56,994				48,824				27,208				59,229				56,850			69,306				33,260			25,689			33,596			149,483		131,363			130,110
	Total gross profit	$	731,983			$	712,837			$	655,309			$	556,914			$	570,126		$	689,184			$	260,289		$	218,570		$	271,039		$	1,549,186	$	1,501,533		$	1,615,532
	-1	Includes gross profit from deals with local and national merchants and through local events.

Quarterly_Results_Quarterly_Re

Quarterly Results Quarterly Results (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Results [Abstract]
Schedule of Quarterly Financial Information [Table Text Block]	The following table represents data from the Company's unaudited consolidated statements of operations for the most recent eight quarters. This quarterly information has been prepared on the same basis as the consolidated financial statements and includes all normal recurring adjustments necessary to fairly state the information for the periods presented. The results of operations of any quarter are not necessarily indicative of the results that may be expected for any future period (in thousands, except per share amounts).
			Quarter Ended
			Dec. 31,		Sept. 30,			June 30,			Mar. 31,			Dec. 31,			Sept. 30,			June 30,			Mar. 31,
			2014		2014			2014			2014			2013			2013			2013			2013
	Consolidated Statements of Operations Data:
	Revenue		$	925,421	$	757,054		$	751,576		$	757,637		$	768,447		$	595,059		$	608,747		$	601,402
	Cost of revenue		531,962		376,910			361,714			371,916			390,239			235,437			224,053			222,393
	Gross profit		393,459		380,144			389,862			385,721			378,208			359,622			384,694			379,009
	Income (loss) from operations		18,394		(5,429		)	(7,854		)	(19,953		)	13,352			13,812			27,412			21,178
	Net income (loss) (1)		11,384		(19,018		)	(20,922		)	(35,363		)	(78,861		)	(1,292		)	(5,551		)	(3,242		)
	Net income (loss) attributable to Groupon, Inc. (1)		8,788		(21,208		)	(22,875		)	(37,795		)	(81,247		)	(2,580		)	(7,574		)	(3,992		)
	Net earnings (loss) per share
	Basic		$0.01		($0.03)			($0.03)			($0.06)			($0.12)			$0.00			($0.01)			($0.01)
	Diluted		$0.01		($0.03)			($0.03)			($0.06)			($0.12)			$0.00			($0.01)			($0.01)
	Weighted average number of shares outstanding
	Basic		671,885,967		669,526,524			675,538,392			682,378,690			668,046,073			666,432,848			662,361,436			658,800,417
	Diluted		681,543,847		669,526,524			675,538,392			682,378,690			668,046,073			666,432,848			662,361,436			658,800,417
	-1	Net loss and net loss attributable to Groupon, Inc. for the quarter ended December 31, 2013 included an impairment of the Company's investment in F-tuan of $85.5 million ($77.8 million, net of tax). See Note 6 "Investments."

Summary_of_Significant_Account2

Summary of Significant Accounting Policies Allowance for Doubtful Accounts (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Allowance for Doubtful Accounts [Abstract]
Allowance for Doubtful Accounts Receivable	$2.20	$0.70

Summary_of_Significant_Account3

Summary of Significant Accounting Policies Bad Debt Expense (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Bad Debt Expense [Abstract]
Provision for Doubtful Accounts	$2.30	$0.70	$0.60

Summary_of_Significant_Account4

Summary of Significant Accounting Policies Restricted Cash (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Restricted Cash [Abstract]
Restricted Cash and Cash Equivalents, Current	$12,019,000	$14,579,000
Restricted Cash and Cash Equivalents, Noncurrent	$5,200,000	$400,000

Summary_of_Significant_Account5

Summary of Significant Accounting Policies Internal Use Software Life (Details) (Internally-developed software [Member])	12 Months Ended
	Dec. 31, 2014
Internally-developed software [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	2 years 0 months 0 days

Summary_of_Significant_Account6

Summary of Significant Accounting Policies Foreign Currency (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Foreign Currency [Abstract]
Foreign exchange (losses) gains, net	$31,526	$10,271	($1,403)

Business_Combinations_and_Acqu2

Business Combinations and Acquisitions of Noncontrolling Interests Business Combinations (Details) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Business Acquisition [Line Items]
Number of Businesses Acquired	6
Business Combination, External Transaction Costs	$3,713		$3,160
Purchase Price Allocation [Abstract]
Business Combination, Cash and Equivalents			2,000		2,000
Goodwill	447,810		220,827		206,684
Ticket Monster [Member]
Business Acquisition [Line Items]
Common stock issued in connection with acquisition of business, shares	13,825,283
Consideration Transferred [Abstract]
Business Combinations, cash transferred	96,496
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable	162,862
Business Combination, Consideration Transferred	259,358
Purchase Price Allocation [Abstract]
Business Combination, Cash and Equivalents	24,768
Business Combination, Current Assets, Receivables	17,732
Business Combination, Current Assets, Deferred Income Taxes	1,264
Business Combination, Current Assets, Prepaid Expense and Other Assets	829
Business Combination, Property, Plant, and Equipment	5,944
Goodwill	218,692
Business Combination, Other Noncurrent Assets	3,033
Business Combination, Assets	381,356
Business Combination, Current Liabilities, Accounts Payable	5,951
Business Combination, Accrued Merchant and Supplier Payables	82,934
Business Combinations, Accrued Expenses	22,700
Business Combination, Current Liabilities, Other	3,482
Business Combination, Deferred Tax Liabilities Noncurrent	1,264
Business Combination, Noncurrent Liabilities, Other	5,667
Business Combination, Liabilities	121,998
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net	259,358
Ticket Monster [Member] | Subscriber Relationships [Member]
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life	5 years 0 months 0 days
Purchase Price Allocation [Abstract]
Business Combination, Intangible assets	57,022	[1]
Ticket Monster [Member] | Merchant Relationships [Member]
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life	3 years 0 months 0 days
Purchase Price Allocation [Abstract]
Business Combination, Intangible assets	32,176	[1]
Ticket Monster [Member] | Developed Technology [Member]
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life	2 years 0 months 0 days
Purchase Price Allocation [Abstract]
Business Combination, Intangible assets	571	[1]
Ticket Monster [Member] | Trade names [Member]
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life	5 years 0 months 0 days
Purchase Price Allocation [Abstract]
Business Combination, Intangible assets	19,325	[1]
Ideeli [Member]
Consideration Transferred [Abstract]
Business Combination, Consideration Transferred	42,698
Purchase Price Allocation [Abstract]
Business Combination, Cash and Equivalents	79
Business Combination, Current Assets, Receivables	988
Business Combination, Current Assets, Deferred Income Taxes	640
Business Combination, Current Assets, Prepaid Expense and Other Assets	22,081
Business Combination, Property, Plant, and Equipment	8,173
Goodwill	4,203
Business Combination, Deferred Tax Assets Noncurrent	8,877
Business Combination, Assets	62,131
Business Combination, Current Liabilities, Accounts Payable	1,640
Business Combination, Accrued Merchant and Supplier Payables	4,092
Business Combinations, Accrued Expenses	9,118
Business Combination, Current Liabilities, Other	482
Business Combination, Deferred Tax Liabilities Noncurrent	348
Business Combination, Noncurrent Liabilities, Other	3,753
Business Combination, Liabilities	19,433
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net	42,698
Ideeli [Member] | Subscriber Relationships [Member]
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life	3 years 0 months 0 days
Purchase Price Allocation [Abstract]
Business Combination, Intangible assets	5,490	[1]
Ideeli [Member] | Brand Relationships [Member]
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life	5 years 0 months 0 days
Purchase Price Allocation [Abstract]
Business Combination, Intangible assets	7,100	[1]
Ideeli [Member] | Trade names [Member]
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life	5 years 0 months 0 days
Purchase Price Allocation [Abstract]
Business Combination, Intangible assets	4,500	[1]
Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Common stock issued in connection with acquisition of business, shares	1,429,897
Number of Businesses Acquired	4		7		10
Consideration Transferred [Abstract]
Business Combinations, cash transferred	17,364		9,459		49,013
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable	11,110		3,051
Business Combination, Consideration Transferred, Liabilities Incurred					2,485
Business Combination, Contingent Consideration	4,388		3,567		3,400
Business Combination, Consideration Transferred	32,862		16,077		54,898
Purchase Price Allocation [Abstract]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net	-396		1,728		1,750
Business Combination, Cash and Equivalents	200
Business Combination, Property, Plant, and Equipment			99		165
Goodwill	27,150		9,504		39,170
Business Combination, Deferred Tax Liabilities Noncurrent	398		731		2,207
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net	32,862		16,077		54,898
Series of Individually Immaterial Business Acquisitions [Member] | Subscriber Relationships [Member]
Purchase Price Allocation [Abstract]
Business Combination, Intangible assets	2,555	[2]	1,928	[2]	170	[2]
Series of Individually Immaterial Business Acquisitions [Member] | Merchant Relationships [Member]
Purchase Price Allocation [Abstract]
Business Combination, Intangible assets			757	[2]	1,500	[2]
Series of Individually Immaterial Business Acquisitions [Member] | Developed Technology [Member]
Purchase Price Allocation [Abstract]
Business Combination, Intangible assets	3,372	[2]	2,742	[2]	14,350	[2]
Series of Individually Immaterial Business Acquisitions [Member] | Brand Relationships [Member]
Purchase Price Allocation [Abstract]
Business Combination, Intangible assets	579	[2]
Series of Individually Immaterial Business Acquisitions [Member] | Other Intangible Assets [Member]
Purchase Price Allocation [Abstract]
Business Combination, Intangible assets			$50	[2]
Maximum [Member]
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life	5 years 0 months 0 days
Maximum [Member] | Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life	5 years 0 months 0 days		5 years 0 months 0 days		5 years 0 months 0 days
Minimum [Member]
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life	1 year 0 months 0 days
Minimum [Member] | Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life	1 year 0 months 0 days		1 year 0 months 0 days		1 year 0 months 0 days
[1]	The estimated useful lives of the acquired intangible assets are 5 years for subscriber relationships, 3 years for merchant relationships, 2 years for developed technology and 5 years for trade name.
[2]	Acquired intangible assets have estimated useful lives of between 1 and 5 years.

Business_Combinations_and_Acqu3

Business Combinations and Acquisitions of Noncontrolling Interests Business Acquisitions, Pro Forma Information (Details) (USD $)	12 Months Ended
	Dec. 31, 2014
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Business Acquisition, Pro Forma Revenue	$2,763,639,000
Business Acquisition, Pro Forma Net Income (Loss)	-217,613,000
Ticket Monster [Member]
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual	-45,400,000
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual	149,600,000
Ideeli [Member]
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual	-12,300,000
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual	$82,400,000

Business_Combinations_and_Acqu4

Business Combinations and Acquisitions of Noncontrolling Interests Business Combinations and Acquisitions of Noncontrolling interests Purchases of Additional Interests in Consolidated Subsidiaries (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2012	Dec. 31, 2013
Business Acquisition [Line Items]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Purchase of Interest by Parent	$3.90	$16.70
Cash Payment [Member]
Business Acquisition [Line Items]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Purchase of Interest by Parent		14.1	2
Stock-based compensation awards settlement		14	1.2
Common Class A [Member]
Business Acquisition [Line Items]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Purchase of Interest by Parent		0.6
Stock-based compensation awards settlement		2.3
Deferred Compensation, Share-based Payments [Member]
Business Acquisition [Line Items]
Deferred Compensation Arrangement with Individual, Compensation Expense		10.5
Cash [Member]
Business Acquisition [Line Items]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Purchase of Interest by Parent	2.3	16.1
Stock-based compensation awards settlement		15.2
Other Current Liabilities [Member]
Business Acquisition [Line Items]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Purchase of Interest by Parent	1
Other Noncurrent Liabilities [Member]
Business Acquisition [Line Items]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Purchase of Interest by Parent	$0.60

Property_Equipment_and_Softwar2

Property, Equipment and Software, Net (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Property, equipment and software, gross	$377,594,000		$244,700,000
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	-195,119,000		-110,277,000
Property, equipment and software, net	182,475,000		134,423,000
Capital Leased Assets, Gross	48,000,000		11,800,000
Depreciation and amortization of property, equipment and software	97,799,000		67,823,000		35,891,000
Capital Leases, Income Statement, Amortization Expense	7,200,000		2,100,000
Capitalized Computer Software, Net	61,800,000		47,900,000
Capitalized Computer Software, Amortization	42,100,000		25,200,000		3,400,000
Warehouse equipment [Member]
Property, Plant and Equipment [Line Items]
Property, equipment and software, gross	4,859,000		3,997,000
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, equipment and software, gross	18,610,000		13,526,000
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, equipment and software, gross	39,900,000		35,830,000
Office and telephone equipment [Member]
Property, Plant and Equipment [Line Items]
Property, equipment and software, gross	4,448,000		5,062,000
Purchased Software [Member]
Property, Plant and Equipment [Line Items]
Property, equipment and software, gross	40,448,000		22,499,000
Computer hardware [Member]
Property, Plant and Equipment [Line Items]
Property, equipment and software, gross	135,731,000	[1]	84,673,000	[1]
Internally-developed software [Member]
Property, Plant and Equipment [Line Items]
Property, equipment and software, gross	133,598,000		79,113,000
Selling, General and Administrative Expenses [Member]
Property, Plant and Equipment [Line Items]
Capitalized Computer Software, Amortization	30,400,000		17,300,000
Cost of Sales [Member]
Property, Plant and Equipment [Line Items]
Capitalized Computer Software, Amortization	$11,700,000		$7,900,000
[1]	(1)Includes computer hardware acquired under capital leases of $48.0 million and $11.8 million as of DecemberB 31, 2014 and 2013, respectively.

Goodwill_and_Other_Intangible_2

Goodwill and Other Intangible Assets Goodwill Activity by Segment (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Goodwill [Roll Forward]
Goodwill, beginning of period	$220,827		$206,684
Goodwill, related to acquisitions	250,045		9,504
Goodwill, other adjustments	-23,062	[1]	4,639	[1]
Goodwill, end of period	447,810		220,827
North America [Member]
Goodwill [Roll Forward]
Goodwill, beginning of period	85,457		79,276
Reallocation to new segments			0
Goodwill, related to acquisitions	31,353		4,893
Goodwill, other adjustments	-92	[1]	1,288	[1]
Goodwill, end of period	116,718		85,457
International [Domain]
Goodwill [Roll Forward]
Goodwill, beginning of period	0		127,408
Reallocation to new segments			-124,770
Goodwill, related to acquisitions	0		0
Goodwill, other adjustments	0	[1]	-2,638	[1]
Goodwill, end of period	0		0
EMEA [Member]
Goodwill [Roll Forward]
Goodwill, beginning of period	115,669		0
Reallocation to new segments			-105,347
Goodwill, related to acquisitions	0		4,611
Goodwill, other adjustments	-13,490	[1]	5,711	[1]
Goodwill, end of period	102,179		115,669
ROW [Member]
Goodwill [Roll Forward]
Goodwill, beginning of period	19,701		0
Reallocation to new segments			-19,423
Goodwill, related to acquisitions	218,692		0
Goodwill, other adjustments	-9,480	[1]	278	[1]
Goodwill, end of period	$228,913		$19,701
[1]	(1)Represents the impact of changes in foreign exchange rates on goodwill.

Goodwill_and_Other_Intangible_3

Goodwill and Other Intangible Assets Other Intangible Assets (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value, Intangible Assets	$223,108	$101,280
Accumulated Amortization, Intangible Assets	112,551	72,837
Net Carrying Value, Intangible Assets	110,557	28,443
Subscriber Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value, Intangible Assets	103,858	45,541
Accumulated Amortization, Intangible Assets	48,754	30,866
Net Carrying Value, Intangible Assets	55,104	14,675
Merchant Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value, Intangible Assets	39,448	9,186
Accumulated Amortization, Intangible Assets	18,677	7,991
Net Carrying Value, Intangible Assets	20,771	1,195
Trade names [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value, Intangible Assets	29,190	6,739
Accumulated Amortization, Intangible Assets	10,666	6,739
Net Carrying Value, Intangible Assets	18,524	0
Developed Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value, Intangible Assets	25,903	23,038
Accumulated Amortization, Intangible Assets	21,989	19,547
Net Carrying Value, Intangible Assets	3,914	3,491
Brand Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value, Intangible Assets	7,664
Accumulated Amortization, Intangible Assets	1,486
Net Carrying Value, Intangible Assets	6,178
Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value, Intangible Assets	17,045	16,776
Accumulated Amortization, Intangible Assets	10,979	7,694
Net Carrying Value, Intangible Assets	$6,066	$9,082

Goodwill_and_Other_Intangible_4

Goodwill and Other Intangible Assets Estimated Future Amortization Expense (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	$47,122	$21,626	$19,910
Finite-Lived Intangible Assets, Net, Amortization Expense [Abstract]
2015	40,495
2016	33,707
2017	18,653
2018	17,617
2019	85
Thereafter	0
Total - Finite Lived Intangible Asset, Amortization Expense	$110,557
Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	1 year 0 months 0 days
Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	5 years 0 months 0 days

Investments_Investments_Table_

Investments Investments Table (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012	Jun. 30, 2012	Sep. 30, 2013
Schedule of Cost and Equity Method Investments [Line Items]
Cost method investments	$15,630,000		$15,788,000			$128,100,000
Equity method investments	1,231,000		1,690,000		495,000
Total cost and equity method investments	16,861,000		17,478,000
Available-for-sale securities	7,437,000		3,174,000
Available-for-Sale Securities, Ownership Percentage			19.00%
Total investments	24,298,000		20,652,000
Payments to Acquire Available-for-sale Securities	4,599,000
Payments to Acquire Cost Method Investment		2,100,000		13,600,000		25,000,000
Convertible debt securities [Member]
Schedule of Cost and Equity Method Investments [Line Items]
Available-for-sale securities	2,527,000		3,174,000
Convertible debt securities [Member]
Schedule of Cost and Equity Method Investments [Line Items]
Available-for-sale securities			3,174,000
Redeemable preferred shares [Member]
Schedule of Cost and Equity Method Investments [Line Items]
Available-for-sale securities	4,910,000		0
Maximum [Member]
Schedule of Cost and Equity Method Investments [Line Items]
Equity Method Investments, Ownership Percentage	50.00%		50.00%
Available-for-Sale Securities, Ownership Percentage	19.00%
Maximum [Member] | Cost-method Investments [Member]
Schedule of Cost and Equity Method Investments [Line Items]
Cost Method Investments, Ownership Percentage	19.00%		19.00%
Minimum [Member]
Schedule of Cost and Equity Method Investments [Line Items]
Equity Method Investments, Ownership Percentage	21.00%		21.00%
Available-for-Sale Securities, Ownership Percentage	17.00%
Minimum [Member] | Cost-method Investments [Member]
Schedule of Cost and Equity Method Investments [Line Items]
Cost Method Investments, Ownership Percentage	6.00%		6.00%
F-Tuan [Member]
Schedule of Cost and Equity Method Investments [Line Items]
Cost method investments						128,100,000
Cost Method Investments, Ownership Percentage			19.10%			19.10%
Payments to Acquire Cost Method Investment						$25,000,000	$8,000,000

Investments_Availableforsale_S

Investments Available-for-sale Securities (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	$6,629	$3,370
Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax	808	-196
Available-for-sale securities	7,437	3,174
Convertible debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	2,030	3,370
Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax	497	-196
Available-for-sale securities	2,527	3,174
Redeemable preferred shares [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	4,599	0
Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax	311	0
Available-for-sale securities	$4,910	$0

Investments_OtherThanTemporary

Investments Other-Than-Temporary-Impairment (Details) (USD $)	3 Months Ended	6 Months Ended	12 Months Ended
	Dec. 31, 2013	Jun. 30, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Other-Than-Temporary-Impairment [Abstract]
Impairment of investments	$77,800,000		$2,036,000	$85,925,000	$50,553,000
Other-than-temporary impairment of available-for-sale security			1,340,000	0	0
Fair Value Inputs, Discount Rate		25.00%			30.00%
Other than Temporary Impairment Losses, Investments	85,500,000		2,036,000	85,925,000	50,553,000
Equity Method Investment, Other than Temporary Impairment					1,200,000
F-Tuan [Member]
Other-Than-Temporary-Impairment [Abstract]
Other than Temporary Impairment Losses, Investments				$85,500,000	$50,600,000

Investments_Investments_in_ECo

Investments Investments in E-Commerce and Life Media (F-Tuan) (Details) (USD $)	3 Months Ended	6 Months Ended	12 Months Ended
	Dec. 31, 2013	Jun. 30, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Mar. 31, 2013	Sep. 30, 2013
Investment [Line Items]
Payments to Acquire Cost Method Investment		$25,000,000				$2,100,000	$13,600,000
Gain (Loss) on Investments					56,032,000
Fair Value Inputs, Discount Rate		25.00%			30.00%
investment Cost Method and AFS Debt Security					77,500,000
Other than Temporary Impairment Losses, Investments	85,500,000		2,036,000	85,925,000	50,553,000
E-commerce [Member]
Investment [Line Items]
Equity Method Investments, Ownership Percentage		49.80%
F-Tuan [Member]
Investment [Line Items]
Payments to Acquire Cost Method Investment		25,000,000						8,000,000
Cost Method Investments, Ownership Percentage	19.10%	19.10%		19.10%
Preferred Stock, Liquidation Preference, Value	85,500,000			85,500,000
Other than Temporary Impairment Losses, Investments				85,500,000	50,600,000
August 2013 [Domain] | F-Tuan [Member]
Investment [Line Items]
Payments to Acquire Cost Method Investment								6,500,000
October 2013 [Domain] [Domain] | F-Tuan [Member]
Investment [Line Items]
Payments to Acquire Cost Method Investment	$1,500,000			$1,500,000

Supplemental_Consolidated_Bala2

Supplemental Consolidated Balance Sheet and Statement of Operations Information (Details) (USD $)	3 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Interest and Other Income [Abstract]
Interest income			$1,564		$1,721		$2,522
Interest expense			-907		-291		0
Gain on E-Commerce transaction			0		0		56,032
Impairments of investment	-85,500		-2,036		-85,925		-50,553
Loss on equity method investments			-459		-44		-9,925
Foreign exchange (losses) gains, net			-31,526		-10,271		1,403
Other Income			11		147
Other Expenses							-3,238
Other expense, net			-33,353		-94,663		-3,759
Prepaid Expense and Other Assets, Current [Abstract]
Current portion of unamortized tax effects on intercompany transactions	28,502		14,193		28,502
Finished goods inventories	57,097		57,134		57,097
Prepaid expenses	29,404		42,231		29,404
Restricted cash	14,579		12,019		14,579
Income taxes receivable	39,994		41,788		39,994
VAT receivable	12,966		17,746		12,966
Prepaid marketing	17,301		7,443		17,301
Other	10,572		15,437		10,572
Total prepaid expenses and other current assets	210,415		207,991		210,415
Merchant and Supplier Payables [Abstract]
Accrued merchant payables	518,233		632,605		518,233
Accrued supplier payables	234,710	[1]	277,962	[1]	234,710	[1]
Total accrued merchant and supplier payables	752,943		910,567		752,943
Accrued Expenses [Abstract]
Marketing	12,001		15,962		12,001
Refunds reserve	38,597		33,238		38,597
Payroll and benefits	64,966		65,743		64,966
Customer credits	44,728		44,463		44,728
Professional fees	18,906		14,292		18,906
Other	47,788		56,654		47,788
Total accrued expenses	226,986		230,352		226,986
Current liabilities [Abstract]:
Income taxes payable	21,994		14,461		21,994
VAT payable	37,627		33,436		37,627
Sales taxes payable	10,412		9,042		10,412
Deferred revenue	47,259		43,903		47,259
Capital lease obligations	3,636		14,872		3,636
Other	11,790		14,598		11,790
Total other current liabilities	132,718		130,312		132,718
Liabilities, Noncurrent [Abstract]
Long-term tax liabilities	109,286		82,138		109,286
Deferred rent	9,148		13,200		9,148
Capital lease obligations	5,665		23,387		5,665
Other	7,598		17,559		7,598
Total other non-current liabilities	131,697		136,284		131,697
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Foreign currency translation adjustments, beginning of period			24,952		12,393
Unrealized loss on available-for-sale securities, net of tax, beginning of period			-122		53
Accumulated other comprehensive income (loss), pension and other postretirement benefit plans, net of tax, beginning of period			0		0
Accumulated other comprehensive income, beginning of period			24,830		12,446
Foreign currency translation adjustments			11,625		12,933		425
Other comprehensive income (loss) before reclassification adjustments			10,102
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax			-1,500		0
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Reclassification Adjustments, Net of Tax			1,500		0		0
Reclassification adjustment for impairment included in net loss			831		0		0
Other comprehensive income			10,746		12,758		478
Foreign currency translation adjustments, end of period	24,952		36,764		24,952		12,393
Unrealized loss on available-for-sale securities, net of tax, end of period	-122		499		-122		53
Accumulated other comprehensive income (loss), pension and other postretirement benefit plans, net of tax, end of period	0		-1,500		0		0
Accumulated other comprehensive income, end of period	24,830		35,763		24,830		12,446
Other-than-temporary impairment of available-for-sale security			1,340		0		0
Tax effect			-509		0		0
Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Foreign currency translation adjustments			11,812		12,559
Other comprehensive income (loss) before reclassification adjustments			11,812
Reclassification adjustment for impairment included in net loss			0
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Unrealized gain (loss) on available-for-sale debt security, net of tax			621		-175
Other comprehensive income (loss) before reclassification adjustments			-210
Reclassification adjustment for impairment included in net loss			831
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Reclassification adjustment for impairment included in net loss			0
Parent [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Foreign currency translation adjustments			-11,812		-12,559		535
Unrealized gain (loss) on available-for-sale debt security, net of tax			621		-175		53
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Reclassification Adjustments, Net of Tax			1,500
Other comprehensive income			$10,933		$12,384
[1]	(1)Amounts include payables to suppliers of inventories and providers of shipping and fulfillment services.

Commitments_and_Contingencies_2

Commitments and Contingencies Operating Leases (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating Leased Assets [Line Items]
Operating Leases, Rent Expense	$55,000,000	$42,300,000	$43,100,000
Amortization period of leasehold improvements	5 years 0 months 0 days
2015	53,776,000
2016	49,094,000
2017	38,628,000
2018	27,659,000
2019	11,455,000
Thereafter	21,514,000
Total minimum lease payments	$202,126,000
Maximum [Member]
Operating Leased Assets [Line Items]
Rent Escalation	9.00%
Lessee Leasing Arrangements, Operating Leases, Term of Contract	7 years 0 months 0 days
Lessee Leasing Arrangements, Operating Leases, Renewal Term	5 years 0 months 0 days
Minimum [Member]
Operating Leased Assets [Line Items]
Rent Escalation	2.00%
Lessee Leasing Arrangements, Operating Leases, Term of Contract	5 years 0 months 0 days
Lessee Leasing Arrangements, Operating Leases, Renewal Term	1 year 0 months 0 days

Commitments_and_Contingencies_3

Commitments and Contingencies Capital Leases (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Capital Leased Assets [Line Items]
2015	$14,936
2016	14,136
2017	9,424
2018	697
2019	522
Thereafter	0
Total minimum lease payments	39,715
Less: Amount representing interest	-1,456
Present value of net minimum capital lease payments	38,259
Less: Current portion of capital lease obligations	-14,872	-3,636
Total long-term capital lease obligations	$23,387	$5,665

Commitments_and_Contingencies_4

Commitments and Contingencies Purchase Obligations (Details) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Long-term Purchase Commitment [Line Items]
2015	$33,636
2016	21,922
2017	5,730
2018	8
2019	4
Thereafter	0
Total purchase obligations	$61,300

Commitments_and_Contingencies_5

Commitments and Contingencies Legal Matters (Details) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2014
COMMITMENTS AND CONTINGENCIES [Abstract]
Restatement of Prior Year Revenue	$14,300,000
Restatement of Prior Year Operating Income	30,000,000
Restatement of Prior Year Income, Net of Tax	22,600,000
Impact of Restatement on Earnings Per Share, Basic	$0.04
Litigation Settlement, Expense		8,500,000
Loss Contingency, Range of Possible Loss, Maximum			$46,500,000

Revolving_Credit_Agreement_Det

Revolving Credit Agreement (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	250,000
Unrestricted cash covenant	400,000
Line of Credit Facility, Cash Institution Covenant	200,000
Line of Credit [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	45,000
Minimum [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Interest Rate Description	0.0025
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.20%
Maximum [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Interest Rate Description	0.02
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.35%

Stockholders_Equity_Initial_Pu

Stockholders' Equity Initial Public Offering, Convertible Preferred Stock and Common Stock (Details)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2014
	NumberofClasses
Preferred Stock, Shares Authorized		50,000,000
Classes of common stock, number	3

Stockholders_Equity_Repurchase

Stockholders' Equity Repurchase Program (Details) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Employee Stock Purchase Plan [Line Items]
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$101,533
Common Class A [Member]
Employee Stock Purchase Plan [Line Items]
Stock Repurchase Program, Authorized Amount	300,000
Stock Repurchased During Period, Shares	22,806,304	4,432,800
Stock Repurchased During Period, Value	$151,880	$46,600

Compensation_Arrangements_Comp3

Compensation Arrangements Compensation Arrangement Stock Plans (Details) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred Stock, Shares Authorized	50,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	44,043,631
Stock-based compensation	$122,019	$121,462	$104,117
Employee Service Share-based Compensation, Allocation of Recognized Period Costs, Capitalized Amount	11,244	9,100	9,700
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$221,700
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	1 year 3 months 18 days
Employee Stock Purchase Plan, shares authorized	10,000,000
Employee Stock Purchase Plan, issued shares	857,171	774,288
2008 Plan [Domain]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock, Shares Authorized	64,618,500
2010 Plan [Domain]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock, Shares Authorized	20,000,000
2011 Plan [Domain]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock, Shares Authorized	50,000,000

Compensation_Arrangements_Comp4

Compensation Arrangements Compensation Arrangement Option Activity (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	25.00%
Aggregate Intrinsic Value [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value	$6,500,000	$30,000,000	$75,200,000
Stock Options [Member]
Options [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	3,355,054
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	-1,029,471
Stock Issued During Period, Shares, Share-based Compensation, Forfeited	-62,589
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	2,262,994	3,355,054
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	2,262,994
Weighted-Average Exercise Price [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$1.11
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price	$1.09
Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price	$2.41
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$1.09	$1.11
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$1.09
Weighted Average Remaining Contractual Term [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	5 years 0 months 10 days	6 years 0 months 15 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	5 years 0 months 10 days	6 years 0 months 15 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	5 years 0 months 10 days
Aggregate Intrinsic Value [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	35,742
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	16,226	35,742
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value	$16,226

Compensation_Arrangements_Comp5

Compensation Arrangements Compensation Arrangement Restricted Stock (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights	0.25
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value		$7.23	$8.99
Stock Issued During Period, Value, Restricted Stock Award, Gross	$139.80	$126.50	$50.20
Restricted Stock Units (RSUs) [Member]
Restricted Stock Units [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	41,648,055
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	29,568,490
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	-17,323,096
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	-12,555,522
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	41,337,927
Weighted Average Grant Date Fair Value [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$8.06
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$7.59
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	$8.07
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$7.96
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$7.78

Compensation_Arrangements_Comp6

Compensation Arrangements Compensation Arrangement Performance Share Units (Details) (USD $)	12 Months Ended
	Dec. 31, 2014
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance Share Units, Shares Granted	2,000,000
Compensation Arrangement Performance Share Units [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	1,983,232
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	-967,388
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	1,015,844
Weighted Average Grant Date Fair Value [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$8.07
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	$0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$8.07
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$8.07
Performance condition not met [Member]
Compensation Arrangement Performance Share Units [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	-800,000

Compensation_Arrangements_Comp7

Compensation Arrangements Compensation Arrangement Restricted Stock Award (Details) (Restricted Stock [Member], USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Restricted Stock [Member]
Restricted Stock [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	97,677
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	-50,481
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	-13,129
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	34,067	97,677
Weighted Average Grant Date Fair Value [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$14
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	$14.54
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$17.07
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$15.53	$14
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value	$0.70	$4.10	$10.20

Compensation_Arrangements_Comp8

Compensation Arrangements Compensation Arrangement Subsidiary Awards (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Share-based Liabilities Paid	$17
Shares issued to settle liability-classified awards, shares	660,539
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		3 years 0 months 0 days
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		4 years 0 months 0 days

Compensation_Arrangements_Swis

Compensation Arrangements Swiss Pension Plans (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Benefit Obligation	$4.90
Defined Benefit Plan, Unfunded Plan	2
Defined Benefit Plan, Net Periodic Benefit Cost	$0.60

Income_Taxes_Text_Details

Income Taxes Text (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income (Loss) from Continuing Operations before Income Taxes, Domestic	($20,057,000)	$62,021,000	$88,638,000
Income (Loss) from Continuing Operations before Income Taxes, Foreign	-28,138,000	-80,930,000	6,304,000
(Loss) income before provision for income taxes	-48,195,000	-18,909,000	94,942,000
Current Income Tax Expense (Benefit)	26,830,000	88,092,000	153,624,000
Deferred income taxes	-11,106,000	-18,055,000	-7,651,000
Provision for income taxes	15,724,000	70,037,000	145,973,000
Effective Income Tax Rate Reconciliation, Amount [Abstract]
U.S. federal income tax (benefit) provision at statutory rate	-16,868,000	-6,618,000	33,230,000
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount	4,815,000	14,299,000	10,565,000
Effective Income Tax Rate Reconciliation, Disposition of Asset, Amount			17,404,000
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount	-10,051,000	-5,361,000	3,965,000
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount	23,515,000	24,404,000	29,249,000
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount	178,000	837,000	-487,000
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount	13,098,000	35,158,000	31,011,000
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Compensation Cost, Amount	6,503,000	9,000,000	14,641,000
Effective Income Tax Rate Reconciliation, Tax Credit, Research, Amount	-4,693,000	-4,650,000	0
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Other, Amount	-773,000	2,968,000	6,395,000
Components of Deferred Tax Assets and Liabilities [Abstract]
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals	32,379,000	65,356,000
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost	6,911,000	13,462,000
Deferred Tax Assets, Operating Loss Carryforwards	221,674,000	152,271,000
Deferred Tax Assets, Goodwill and Intangible Assets	11,910,000	30,039,000
Deferred Tax Assets, Investments	1,441,000	3,730,000
Deferred Tax Assets, Unrealized Currency Losses	5,011,000	0
Deferred Tax Assets, Other	2,610,000	1,692,000
Deferred Tax Assets, Gross	281,936,000	266,550,000
Deferred Tax Assets, Valuation Allowance	-205,486,000	-173,577,000
Deferred Tax Assets, Net of Valuation Allowance	76,450,000	92,973,000
Deferred Tax Liabilities, Unrealized Currency Transaction Gains	0	-3,034,000
Deferred Tax Liabilities, Prepaid Expenses	-1,455,000	-1,078,000
Deferred Tax Liabilities, Property, Plant and Equipment	-25,159,000	-19,239,000
Deferred Tax Liabilities, Tax Deferred Income	-25,013,000	-64,154,000
Deferred Tax Liabilities, Gross	-51,627,000	-87,505,000
Deferred Tax Assets, Net	24,823,000	5,468,000
Accumulated deficit	-921,960,000	-848,870,000
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount		9,600,000
Deferred Tax Assets, Operating Loss Carryforwards, Domestic	121,200,000
Deferred Tax Assets, Operating Loss Carryforwards, State and Local	270,500,000
Deferred Tax Assets, Operating Loss Carryforwards, Foreign	714,900,000
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits, beginning balance	110,305,000	85,481,000	55,127,000
Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions	5,489,000	10,494,000	602,000
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions	-27,875,000	-2,103,000	-790,000
Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions	17,348,000	14,565,000	29,465,000
Unrecognized Tax Benefits, Decrease Resulting from Foreign Currency Translation	-6,946,000
Unrecognized Tax Benefits, Increase Resulting from Foreign Currency Translation		1,868,000	1,077,000
Unrecognized tax benefits, ending balance	98,321,000	110,305,000	85,481,000
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	72,300,000	80,000,000	39,300,000
Income Tax Examination, Penalties and Interest Expense	1,100,000	3,300,000	2,300,000
Income Tax Examination, Penalties and Interest Accrued	5,700,000	5,300,000
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations	21,000,000
Increase (Decrease) in Income Taxes	24,400,000
Potential Change in Unrecognized Tax Benefits	15,600,000
Undistributed Earnings of Foreign Subsidiaries	271,100,000
Current portion of unamortized tax effects on intercompany transactions	14,193,000	28,502,000
Prepaid Expenses and Other Current Assets [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Current portion of unamortized tax effects on intercompany transactions	14,193,000	28,500,000
Other Assets [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Current portion of unamortized tax effects on intercompany transactions		20,400,000
Future amortization through 2015 [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Current portion of unamortized tax effects on intercompany transactions	14,200,000
Domestic Tax Authority [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Increase (Decrease) in Income Taxes	7,700,000
Foreign Tax Authority [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Increase (Decrease) in Income Taxes	16,700,000
UNITED STATES
Current Income Tax Expense (Benefit)	-3,518,000	22,321,000	41,551,000
Deferred income taxes	-5,132,000	4,675,000	-2,977,000
State and Local Jurisdiction [Member]
Current Income Tax Expense (Benefit)	69,000	1,693,000	4,778,000
Deferred income taxes	-742,000	-5,687,000	-236,000
International [Domain]
Current Income Tax Expense (Benefit)	30,279,000	64,078,000	107,295,000
Deferred income taxes	($5,232,000)	($17,043,000)	($4,438,000)

Variable_Interest_Entity_Detai

Variable Interest Entity (Details)	12 Months Ended
	Dec. 31, 2014
Variable Interest Entity [Abstract]
Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage	50.00%

Fair_Value_Measurements_Contin

Fair Value Measurements Contingent Obligations (Details) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014
Contingent Obligations [Abstract]
Minimum share price required to prevent contigent obligation	$6.48
Other Acquisition 1 [Member]
Contingent Obligations [Abstract]
Business Combination, Contingent Consideration Arrangements, Change in Range of Outcomes, Contingent Consideration, Liability, Value, High	$1,100

Fair_Value_Measurements_Fair_V

Fair Value Measurements Fair Value, Assets and Liabilities Measured at Fair Value (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	$7,437	$3,174
Fair Value, Measurements, Recurring [Member] | Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	440,596	585,514
Contingent Consideration, Fair Value Disclosure	1,983	606
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	440,596	585,514
Contingent Consideration, Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0	0
Contingent Consideration, Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0	0
Contingent Consideration, Fair Value Disclosure	1,983	606
Convertible debt securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	2,527	3,174
Convertible debt securities [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Convertible debt securities [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Convertible debt securities [Member] | Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	2,527	3,174
Redeemable preferred shares [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	4,910	0
Redeemable preferred shares [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Redeemable preferred shares [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Redeemable preferred shares [Member] | Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	4,910	0
Other Acquisition 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration Arrangements, Change in Range of Outcomes, Contingent Consideration, Liability, Value, High	1,100
Other Acquisitions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration Arrangements, Change in Range of Outcomes, Contingent Consideration, Liability, Value, High	$8,421

Fair_Value_Measurements_Fair_V1

Fair Value Measurements Fair Value, Reconciliation of Level 3 - Assets (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Convertible Debt			$370		$3,000
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities	-1,340		0		0
Cost Method Investments			34982		56940
Convertible debt securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
AFS Securities, Beginning Asset Value	3,174		3,087		0
AFS Debt Security, (losses) included in OCI	693		-283		87
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities	-1,340		0		0
AFS Securities, Ending Asset Value	2,527		3,174		3,087
Unrealized Gains (Losses) Still Held - Assets	-647	[1]	-283	[1]	87	[1]
Redeemable preferred shares [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
AFS Securities, Beginning Asset Value	0		42,539		0
AFS Debt Security, (losses) included in OCI	311		0		0
AFS Securities, Ending Asset Value	4,910		0		42,539
Unrealized Gains (Losses) Still Held - Assets	311	[1]	-85,521	[1]	-14,401	[1]
Purchase of redeemable preferred shares	4,599		8,000		0
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities			($85,521)		($14,401)
[1]	Represents the unrealized losses or gains recorded in earnings and/or other comprehensive income (loss) during the period for assets and liabilities classified as Level 3 that are still held (or outstanding) at the end of the period.

Fair_Value_Measurements_Fair_V2

Fair Value Measurements Fair Value, Reconciliation of Level 3 - Liabilities (Details) (USD $)	9 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Contingent Consideration, Beginning Value	$7,601	$606		$7,601		$11,230
Contingent Consideration, Issuances	3,567	4,388				3,400
Contingent Consideration, Settlements	-4,377	-424				-4,936
Contingent Consideration, Reclass	-3,014	-143				-4,978
(Gain) loss, net from changes in fair value of contingent consideration	-3,171	-2,444		-3,171		897
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Transfers, Net						1,988
Contingent Consideration, Ending Value		1,983		606		7,601
Contingent Consideration, Unrealized Gain Loss		($2,405)	[1]	$360	[1]	$211	[1]
[1]	Represents the unrealized losses or gains recorded in earnings and/or other comprehensive income (loss) during the period for assets and liabilities classified as Level 3 that are still held (or outstanding) at the end of the period.

Fair_Value_Measurements_Fair_V3

Fair Value Measurements Fair Value Measurements Measured at Fair Value (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2012
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cost method investments	$15,630	$15,788		$128,100
Equity method investments	1,231	1,690	495
Cost Method Investments, Fair Value Disclosure	16,134	15,573
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity method investments			495
F-Tuan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cost method investments			34,982
F-Tuan [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cost method investments			$34,982

Fair_Value_Measurements_Financ

Fair Value Measurements Financial Assets and Liabilities, Not Measured at Fair Value (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Jun. 30, 2012
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cost method investments	$15,630	$15,788	$128,100
Cost Method Investments, Fair Value Disclosure	$16,134	$15,573

Loss_Per_Share_of_Class_A_and_2

Loss Per Share of Class A and Class B Common Stock Basic and Diluted Earnings Per Share, 2013, 2012 and 2011 (Details) (USD $)	3 Months Ended									12 Months Ended
	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
Earnings Per Share, Basic [Abstract]
Net loss										($63,919,000)		($88,946,000)		($51,031,000)
Noncontrolling Interest, Change in Redemption Value										0		0		12,604,000
Net income attributable to noncontrolling interests										9,171,000		6,447,000		3,742,000
Net loss attributable to common stockholders	11,384,000	-19,018,000	-20,922,000	-35,363,000	-78,861,000	[1]	-1,292,000	-5,551,000	-3,242,000	-73,090,000		-95,393,000		-67,377,000
Basic, weighted average number of shares outstanding	671,885,967	669,526,524	675,538,392	682,378,690	668,046,073		666,432,848	662,361,436	658,800,417	674,832,393		663,910,194		650,214,119
Basic, net (loss) earnings per share	$0.01	($0.03)	($0.03)	($0.06)	($0.12)		$0	($0.01)	($0.01)	($0.11)		($0.14)		($0.10)
Earnings Per Share, Diluted [Abstract]
Basic, weighted average number of shares outstanding	671,885,967	669,526,524	675,538,392	682,378,690	668,046,073		666,432,848	662,361,436	658,800,417	674,832,393		663,910,194		650,214,119
Diluted, weighted average number of shares outstanding	681,543,847	669,526,524	675,538,392	682,378,690	668,046,073		666,432,848	662,361,436	658,800,417	674,832,393		663,910,194		650,214,119
Diluted, net (loss) earnings per share	$0.01	($0.03)	($0.03)	($0.06)	($0.12)		$0	($0.01)	($0.01)	($0.11)		($0.14)		($0.10)
Common Class A [Member]
Earnings Per Share, Basic [Abstract]
Net loss										-63,691,000		-88,626,000		-50,842,000
Noncontrolling Interest, Change in Redemption Value														12,557,000
Net income attributable to noncontrolling interests										9,138,000		6,424,000		3,728,000
Net loss attributable to common stockholders										-72,829,000		-95,050,000		-67,127,000
Basic, weighted average number of shares outstanding										672,432,417		661,510,218		647,814,143
Basic, net (loss) earnings per share										($0.11)		($0.14)		($0.10)
Earnings Per Share, Diluted [Abstract]
Net Income (Loss) Available to Common Stockholders, Diluted										-72,829,000		-95,050,000		-67,127,000
Reallocation of net income attributable to common stockholders as a result of conversion of Class B										0	[2]	0	[2]	0	[2]
Allocation of net income attributable to common stockholders										-72,829,000		-95,050,000		-67,127,000
Basic, weighted average number of shares outstanding										672,432,417		661,510,218		647,814,143
Conversion of Class B										0	[2]	0	[2]	0	[2]
Employee stock options										0	[2]	0	[2]	0	[2]
Dilutive Securities, Effect on Basic Earnings Per Share, Options and Restrictive Stock Units										0	[2]	0	[2]	0	[2]
Diluted, weighted average number of shares outstanding										672,432,417	[2]	661,510,218	[2]	647,814,143	[2]
Diluted, net (loss) earnings per share										($0.11)		($0.14)		($0.10)
Common Class B [Member]
Earnings Per Share, Basic [Abstract]
Net loss										-228,000		-320,000		-189,000
Noncontrolling Interest, Change in Redemption Value														47,000
Net income attributable to noncontrolling interests										33,000		23,000		14,000
Net loss attributable to common stockholders										-261,000		-343,000		-250,000
Basic, weighted average number of shares outstanding										2,399,976		2,399,976		2,399,976
Basic, net (loss) earnings per share										($0.11)		($0.14)		($0.10)
Earnings Per Share, Diluted [Abstract]
Net Income (Loss) Available to Common Stockholders, Diluted										-261,000		-343,000		-250,000
Reallocation of net income attributable to common stockholders as a result of conversion of Class B										0	[2]	0	[2]	0	[2]
Allocation of net income attributable to common stockholders										-261,000		-343,000		-250,000
Basic, weighted average number of shares outstanding										2,399,976		2,399,976		2,399,976
Conversion of Class B										0	[2]	0	[2]	0	[2]
Employee stock options										0	[2]	0	[2]	0	[2]
Dilutive Securities, Effect on Basic Earnings Per Share, Options and Restrictive Stock Units										$0	[2]	$0	[2]	$0	[2]
Diluted, weighted average number of shares outstanding										2,399,976	[2]	2,399,976	[2]	2,399,976	[2]
Diluted, net (loss) earnings per share										($0.11)		($0.14)		($0.10)
[1]	(1)Net loss and net loss attributable to Groupon, Inc. for the quarter ended December 31, 2013 included an impairment of the Company's investment in F-tuan of $85.5 million ($77.8 million, net of tax). See Note 6 "Investments."
[2]	Conversion of Class B shares into Class A shares and outstanding equity awards have not been reflected in the diluted loss per share calculation for the years ended DecemberB 31, 2014, 2013 and 2012 because the effect would be antidilutive.

Loss_Per_Share_of_Class_A_and_3

Loss Per Share of Class A and Class B Common Stock Schedule of Equity Antidilutive Securities (Details)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities, Amount	45,678	45,956	38,261
Performance share units	2,000
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities, Amount	2,776	5,594	7,713
Restricted Stock Units (RSUs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities, Amount	42,341	39,619	29,699
Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities, Amount	53	298	577
Employee Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities, Amount	508	444	271

Segment_Information_Details

Segment Information (Details) (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]
Number of Reportable Segments									3
Total revenue	$925,421	$757,054	$751,576	$757,637	$768,447	$595,059	$608,747	$601,402	$3,191,688		$2,573,655		$2,334,472
Segment cost of revenue and operating expenses									3,083,242	[1]	2,376,450	[1]	2,130,757	[1]
Segment operating income (loss)									108,446	[1]	197,205	[1]	203,715	[1]
Stock-based compensation									122,019		121,462		104,117
Acquisition-related expense (benefit), net									1,269		-11		897
(Loss) income from operations	18,394	-5,429	-7,854	-19,953	13,352	13,812	27,412	21,178	-14,842		75,754		98,701
Other expense, net									-33,353		-94,663		-3,759
(Loss) income before provision for income taxes									-48,195		-18,909		94,942
Provision for income taxes									15,724		70,037		145,973
Net loss									-63,919		-88,946		-51,031
UNITED STATES
Segment Reporting Information [Line Items]
Total revenue									1,784,600		1,471,900		1,108,400
Switzerland
Segment Reporting Information [Line Items]
Total revenue									468,700
North America [Member]
Segment Reporting Information [Line Items]
Total revenue									1,824,461	[2]	1,521,358	[2]	1,165,700	[2]
Segment cost of revenue and operating expenses									1,755,113	[1]	1,380,746	[1]	1,025,974	[1]
Segment operating income (loss)									69,348	[1]	140,612	[1]	139,726	[1]
Stock-based compensation									99,939		90,877		65,127
Acquisition-related expense (benefit), net									1,125		1,285		-2,780
EMEA [Member]
Segment Reporting Information [Line Items]
Total revenue									961,130		742,915		805,476
Segment cost of revenue and operating expenses									857,062	[1]	631,409	[1]	699,470	[1]
Segment operating income (loss)									104,068	[1]	111,506	[1]	106,006	[1]
Stock-based compensation									9,927		16,263		15,123
Acquisition-related expense (benefit), net									144		-1,296		3,677
ROW [Member]
Segment Reporting Information [Line Items]
Total revenue									406,097		309,382		363,296
Segment cost of revenue and operating expenses									471,067	[1]	364,295	[1]	405,313	[1]
Segment operating income (loss)									-64,970	[1]	-54,913	[1]	-42,017	[1]
Stock-based compensation									12,153		14,322		23,867
Acquisition-related expense (benefit), net									$0		$0		$0
Sales Revenue, Net [Member]
Segment Reporting Information [Line Items]
Concentration of risk, percentage									10.00%
[1]	Segment cost of revenue and operating expenses and segment operating income (loss) exclude stock-based compensation and acquisition-related (benefit) expense, net. This presentation corresponds to the measure of segment profit or loss that the Company's chief operating decision-maker uses in assessing segment performance and making resource allocation decisions. The following table summarizes the Company's stock-based compensation expense and acquisition-related expense (benefit), net by reportable segment for the years ended DecemberB 31, 2014, 2013 and 2012. (in thousands): Year Ended December 31, 2014B 2013B 2012 Stock-based compensationB Acquisition-relatedB Stock-based compensationB Acquisition-relatedB Stock-based compensationB Acquisition-relatedNorth AmericaB $99,939B $1,125B $90,877B $1,285B $65,127B $(2,780)EMEAB 9,927B 144B 16,263B (1,296)B 15,123B 3,677Rest of WorldB 12,153B bB 14,322B bB 23,867B bConsolidatedB $122,019B $1,269B $121,462B $(11)B $104,117B $897Acquisition-related expense (benefit), net for the North America segment includes external transaction costs and gains and losses relating to contingent consideration obligations incurred by U.S. legal entities relating to purchases of businesses that became part of the EMEA and Rest of World segments, which is consistent with the attribution used for internal reporting purposes.
[2]	North America includes revenue from the United States of $1,784.6 million, $1,471.9 million and $1,108.4 million for the years ended DecemberB 31, 2014, 2013 and 2012 respectively. Beginning in September 2013, direct revenue transactions in the EMEA Goods category have been transacted through a Switzerland-based subsidiary. As a result, EMEA includes revenue from Switzerland of $468.7 million for the year ended DecemberB 31, 2014. There were no other individual countries that represented more than 10% of consolidated total revenue for the years ended December 31, 2014, 2013 or 2012.

Segment_Information_Total_Asse

Segment Information Total Assets (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Segment Reporting Information [Line Items]
Total Assets	2,227,597		$2,042,010
UNITED STATES
Segment Reporting Information [Line Items]
Total Assets	1,120,400		1,231,300
North America [Member]
Segment Reporting Information [Line Items]
Total Assets	1,150,417	[1]	1,267,158	[1]
EMEA [Member]
Segment Reporting Information [Line Items]
Total Assets	552,486		616,126
ROW [Member]
Segment Reporting Information [Line Items]
Total Assets	524,694	[1]	158,726	[1]
Korea [Member]
Segment Reporting Information [Line Items]
Total Assets	388,000
Assets, Total [Member]
Segment Reporting Information [Line Items]
Concentration of risk, percentage	10.00%
[1]	(1)North America contains assets from the United States of $1,120.4 million and $1,231.3 million as of December 31, 2014 and 2013, respectively. Rest of World contains assets from the Republic of Korea, including those assets acquired as a part of our acquisition of Ticket Monster described in Note 3 "Business Combinations," of $388.0 million as of December 31, 2014. There were no other individual countries that represented more than 10% of consolidated total assets as of December 31, 2014 and 2013, respectively.

Segment_Information_Tangible_p

Segment Information Tangible property and equipment (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013
Segment Reporting Information [Line Items]
Tangible property and equipment	103,803,000		$75,639,000
North America [Member]
Segment Reporting Information [Line Items]
Tangible property and equipment	63,915,000	[1]	43,126,000	[1]
EMEA [Member]
Segment Reporting Information [Line Items]
Tangible property and equipment	28,721,000		23,413,000
ROW [Member]
Segment Reporting Information [Line Items]
Tangible property and equipment	11,167,000	[2]	9,100,000	[2]
Property, Plant and Equipment [Member]
Segment Reporting Information [Line Items]
Concentration of risk, percentage	10.00%
IRELAND
Segment Reporting Information [Line Items]
Tangible property and equipment	0.12
Switzerland
Segment Reporting Information [Line Items]
Tangible property and equipment	0.11
[1]	Substantially all tangible property and equipment within North America is located in the United States.
[2]	Tangible property and equipment, net located within Ireland represented approximately 12% of the Company's consolidated tangible property and equipment, net as of December 31, 2014. Tangible property and equipment, net located within Switzerland represented approximately 11% of the Company's consolidated tangible property and equipment, net as of December 31, 2013. There were no other individual countries located outside of the United States that represented more than 10% of consolidated tangible property and equipment, net as of December 31, 2014 and 2013.

Segment_Information_Depreciati

Segment Information Depreciation and Amortization (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Depreciation, Depletion and Amortization	$144,921	$89,449	$55,801
North America [Member]
Segment Reporting Information [Line Items]
Depreciation, Depletion and Amortization	83,106	57,700	30,580
EMEA [Member]
Segment Reporting Information [Line Items]
Depreciation, Depletion and Amortization	24,849	24,157	17,546
ROW [Member]
Segment Reporting Information [Line Items]
Depreciation, Depletion and Amortization	$36,966	$7,592	$7,675

Segment_Information_Equity_Met

Segment Information Equity Method Investments (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Equity Method Investments [Abstract]
Equity method investments	$1,231	$1,690	$495

Segment_Information_Capital_Ex

Segment Information Capital Expenditures (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Property, Plant and Equipment, Additions	$31,336	$28,916	$69,327
North America [Member]
Segment Reporting Information [Line Items]
Property, Plant and Equipment, Additions	6,775	14,728	38,543
EMEA [Member]
Segment Reporting Information [Line Items]
Property, Plant and Equipment, Additions	12,945	6,719	26,909
ROW [Member]
Segment Reporting Information [Line Items]
Property, Plant and Equipment, Additions	$11,616	$7,469	$3,875

Segment_Information_Revenue_by

Segment Information Revenue by Segment and Category (Details) (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
Primary Categories									3
Third party and other									$1,627,539		$1,654,654		$1,879,729
Direct									1,564,149		919,001		454,743
Total revenue	925,421	757,054	751,576	757,637	768,447	595,059	608,747	601,402	3,191,688		2,573,655		2,334,472
North America [Member]
Total revenue									1,824,461	[1]	1,521,358	[1]	1,165,700	[1]
EMEA [Member]
Total revenue									961,130		742,915		805,476
ROW [Member]
Total revenue									406,097		309,382		363,296
Local [Member]
Third party and other									1,233,336	[2]	1,283,876		1,389,228	[2]
Direct									0	[2]	1,772	[2]	12,037	[2]
Total revenue									1,233,336	[2]	1,285,648	[2]	1,401,265	[2]
Local [Member] | North America [Member]
Third party and other									674,605		671,846		665,587	[2]
Direct									0	[2]	1,772	[2]	12,037	[2]
Total revenue									674,605	[2]	673,618	[2]	677,624	[2]
Local [Member] | EMEA [Member]
Third party and other									391,179		430,020		501,782	[2]
Direct									0	[2]	0	[2]	0	[2]
Total revenue									391,179	[2]	430,020	[2]	501,782	[2]
Local [Member] | ROW [Member]
Third party and other									167,552	[2]	182,010	[2]	221,859	[2]
Direct									0	[2]	0	[2]	0	[2]
Total revenue									167,552	[2]	182,010	[2]	221,859	[2]
Goods [Member]
Third party and other									216,600		219,870		334,510
Direct									1,564,149		917,229		438,453
Total revenue									1,780,749		1,137,099		772,963
Goods [Member] | North America [Member]
Third party and other									5,966		17,409		60,269
Direct									1,074,913		774,023		391,239
Total revenue									1,080,879		791,432		451,508
Goods [Member] | EMEA [Member]
Third party and other									63,650		133,117		186,495
Direct									442,344		115,881		36,393
Total revenue									505,994		248,998		222,888
Goods [Member] | ROW [Member]
Third party and other									146,984		69,344		87,746
Direct									46,892		27,325		10,821
Total revenue									193,876		96,669		98,567
Travel [Member]
Third party and other													155,991
Direct													4,253
Total revenue									177,603		150,908		160,244
Travel [Member] | North America [Member]
Third party and other									68,977		56,308		36,568
Total revenue									68,977		56,308		36,568
Travel [Member] | EMEA [Member]
Third party and other									63,957		63,897		76,553
Direct													4,253
Total revenue									63,957		63,897		80,806
Travel [Member] | ROW [Member]
Third party and other									44,669		30,703		42,870
Total revenue									$44,669		$30,703		$42,870
[1]	North America includes revenue from the United States of $1,784.6 million, $1,471.9 million and $1,108.4 million for the years ended DecemberB 31, 2014, 2013 and 2012 respectively. Beginning in September 2013, direct revenue transactions in the EMEA Goods category have been transacted through a Switzerland-based subsidiary. As a result, EMEA includes revenue from Switzerland of $468.7 million for the year ended DecemberB 31, 2014. There were no other individual countries that represented more than 10% of consolidated total revenue for the years ended December 31, 2014, 2013 or 2012.
[2]	(1)Includes revenue from deals with local and national merchants and through local events.

Segment_Information_Gross_Prof

Segment Information Gross Profit by Segment and Category (Details) (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
Gross Profit by Category [Line Items]
Gross profit	$393,459	$380,144	$389,862	$385,721	$378,208	$359,622	$384,694	$379,009	$1,549,186		$1,501,533		$1,615,532
North America [Member]
Gross Profit by Category [Line Items]
Gross profit									731,983		712,837		655,309
EMEA [Member]
Gross Profit by Category [Line Items]
Gross profit									556,914		570,126		689,184
ROW [Member]
Gross Profit by Category [Line Items]
Gross profit									260,289		218,570		271,039
Local [Member]
Gross Profit by Category [Line Items]
Gross profit									1,084,139	[1]	1,119,072	[1]	1,171,330	[1]
Local [Member] | Third party and other [Member]
Gross Profit by Category [Line Items]
Gross profit									1,084,139	[1]	1,119,854	[1]	1,169,421	[1]
Local [Member] | Direct [Member]
Gross Profit by Category [Line Items]
Gross profit									0	[1]	-782	[1]	1,909	[1]
Local [Member] | North America [Member]
Gross Profit by Category [Line Items]
Gross profit									581,067	[1]	581,941	[1]	543,625	[1]
Local [Member] | North America [Member] | Third party and other [Member]
Gross Profit by Category [Line Items]
Gross profit									581,067	[1]	582,723	[1]	541,716	[1]
Local [Member] | North America [Member] | Direct [Member]
Gross Profit by Category [Line Items]
Gross profit									0	[1]	-782	[1]	1,909	[1]
Local [Member] | EMEA [Member]
Gross Profit by Category [Line Items]
Gross profit									364,545	[1]	383,725	[1]	453,970	[1]
Local [Member] | EMEA [Member] | Third party and other [Member]
Gross Profit by Category [Line Items]
Gross profit									364,545	[1]	383,725	[1]	453,970	[1]
Local [Member] | EMEA [Member] | Direct [Member]
Gross Profit by Category [Line Items]
Gross profit									0	[1]	0	[1]	0	[1]
Local [Member] | ROW [Member]
Gross Profit by Category [Line Items]
Gross profit									138,527	[1]	153,406	[1]	173,735	[1]
Local [Member] | ROW [Member] | Third party and other [Member]
Gross Profit by Category [Line Items]
Gross profit									138,527	[1]	153,406	[1]	173,735	[1]
Local [Member] | ROW [Member] | Direct [Member]
Gross Profit by Category [Line Items]
Gross profit									0	[1]	0	[1]	0	[1]
Goods [Member]
Gross Profit by Category [Line Items]
Gross profit									315,564		251,098		314,092
Goods [Member] | Third party and other [Member]
Gross Profit by Category [Line Items]
Gross profit									152,032		171,375		282,988
Goods [Member] | Direct [Member]
Gross Profit by Category [Line Items]
Gross profit									163,532		79,723		31,104
Goods [Member] | North America [Member]
Gross Profit by Category [Line Items]
Gross profit									93,922		82,072		84,476
Goods [Member] | North America [Member] | Third party and other [Member]
Gross Profit by Category [Line Items]
Gross profit									5,112		15,319		48,288
Goods [Member] | North America [Member] | Direct [Member]
Gross Profit by Category [Line Items]
Gross profit									88,810		66,753		36,188
Goods [Member] | EMEA [Member]
Gross Profit by Category [Line Items]
Gross profit									133,140		129,551		165,908
Goods [Member] | EMEA [Member] | Third party and other [Member]
Gross Profit by Category [Line Items]
Gross profit									55,434		116,357		168,429
Goods [Member] | EMEA [Member] | Direct [Member]
Gross Profit by Category [Line Items]
Gross profit									77,706		13,194		-2,521
Goods [Member] | ROW [Member]
Gross Profit by Category [Line Items]
Gross profit									88,502		39,475		63,708
Goods [Member] | ROW [Member] | Third party and other [Member]
Gross Profit by Category [Line Items]
Gross profit									91,486		39,699		66,271
Goods [Member] | ROW [Member] | Direct [Member]
Gross Profit by Category [Line Items]
Gross profit									-2,984		-224		-2,563
Travel [Member]
Gross Profit by Category [Line Items]
Gross profit									149,483		131,363		130,110
Travel [Member] | Third party and other [Member]
Gross Profit by Category [Line Items]
Gross profit									149,483		131,363		129,581
Travel [Member] | Direct [Member]
Gross Profit by Category [Line Items]
Gross profit									0		0		529
Travel [Member] | North America [Member]
Gross Profit by Category [Line Items]
Gross profit									56,994		48,824		27,208
Travel [Member] | North America [Member] | Third party and other [Member]
Gross Profit by Category [Line Items]
Gross profit									56,994		48,824		27,208
Travel [Member] | North America [Member] | Direct [Member]
Gross Profit by Category [Line Items]
Gross profit									0		0		0
Travel [Member] | EMEA [Member]
Gross Profit by Category [Line Items]
Gross profit									59,229		56,850		69,306
Travel [Member] | EMEA [Member] | Third party and other [Member]
Gross Profit by Category [Line Items]
Gross profit									59,229		56,850		68,777
Travel [Member] | EMEA [Member] | Direct [Member]
Gross Profit by Category [Line Items]
Gross profit									0		0		529
Travel [Member] | ROW [Member]
Gross Profit by Category [Line Items]
Gross profit									33,260		25,689		33,596
Travel [Member] | ROW [Member] | Third party and other [Member]
Gross Profit by Category [Line Items]
Gross profit									33,260		25,689		33,596
Travel [Member] | ROW [Member] | Direct [Member]
Gross Profit by Category [Line Items]
Gross profit									$0		$0		$0
[1]	(1)Includes gross profit from deals with local and national merchants and through local events.

Related_Party_Transactions_Det

Related Party Transactions (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Boomerang [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Expenses from Transactions with Related Party	$1
InnerWorkings [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Expenses from Transactions with Related Party		1.1
Echo [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Expenses from Transactions with Related Party		$1.90

Quarterly_Results_Details

Quarterly Results (Details) (USD $)	3 Months Ended									12 Months Ended
In Thousands, except 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 Results [Abstract]
Revenues	$925,421	$757,054	$751,576	$757,637	$768,447		$595,059	$608,747	$601,402	$3,191,688	$2,573,655	$2,334,472
Cost of revenue	531,962	376,910	361,714	371,916	390,239		235,437	224,053	222,393	1,642,502	1,072,122	718,940
Gross profit	393,459	380,144	389,862	385,721	378,208		359,622	384,694	379,009	1,549,186	1,501,533	1,615,532
Income (loss) from operations	18,394	-5,429	-7,854	-19,953	13,352		13,812	27,412	21,178	-14,842	75,754	98,701
Net income (loss)	11,384	-19,018	-20,922	-35,363	-78,861	[1]	-1,292	-5,551	-3,242	-73,090	-95,393	-67,377
Net income (loss) attributable to Groupon, Inc.	8,788	-21,208	-22,875	-37,795	-81,247	[1]	-2,580	-7,574	-3,992	-73,090	-95,393	-54,773
Basic, net (loss) earnings per share	$0.01	($0.03)	($0.03)	($0.06)	($0.12)		$0	($0.01)	($0.01)	($0.11)	($0.14)	($0.10)
Diluted, net (loss) earnings per share	$0.01	($0.03)	($0.03)	($0.06)	($0.12)		$0	($0.01)	($0.01)	($0.11)	($0.14)	($0.10)
Basic, weighted average number of shares outstanding	671,885,967	669,526,524	675,538,392	682,378,690	668,046,073		666,432,848	662,361,436	658,800,417	674,832,393	663,910,194	650,214,119
Diluted, weighted average number of shares outstanding	681,543,847	669,526,524	675,538,392	682,378,690	668,046,073		666,432,848	662,361,436	658,800,417	674,832,393	663,910,194	650,214,119
Effect of Fourth Quarter Events [Line Items]
Other than Temporary Impairment Losses, Investments					85,500					2,036	85,925	50,553
Impairment of investments					$77,800					$2,036	$85,925	$50,553
[1]	(1)Net loss and net loss attributable to Groupon, Inc. for the quarter ended December 31, 2013 included an impairment of the Company's investment in F-tuan of $85.5 million ($77.8 million, net of tax). See Note 6 "Investments."

Schedule_II_Valuation_and_Qual1

Schedule II - Valuation and Qualifying Accounts (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances and Reserves, Beginning Balance	$173,577	$159,249	$128,215
Valuation Allowances and Reserves, Charged to Cost and Expense	23,515	24,404	27,751
Valuation Allowances and Reserves, Period Increase (Decrease)	8,394	-10,076	3,283
Valuation Allowances and Reserves, Ending Balance	$205,486	$173,577	$159,249