CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Treasury Stock	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Total Groupon, Inc. Stockholders' Equity	Non-controlling Interests
Beginning balance (in shares) at Dec. 31, 2016		736,531,771
Beginning balance at Dec. 31, 2016	$ 265,062	$ 74	$ 2,112,728		$ (1,099,010)	$ 58,052	$ 264,420	$ 642
Treasury stock, beginning balance (in shares) at Dec. 31, 2016				(171,695,908)
Treasury stock, beginning balance at Dec. 31, 2016				$ (807,424)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of change in accounting principle, net of tax					(3,234)		(3,234)
Cumulative effect of change in accounting principle, net of tax | Accounting Standards Update 2016-16 [Member]	(3,234)
Reclassification for impact of U.S. tax rate change	20,466
Comprehensive income (loss)	419				14,040	(26,208)	(12,168)	12,587
Exercise in stock options (in shares)		102,803
Exercise of stock options	230		230				230
Vesting of restricted stock units and performance share units (in shares)		16,596,562
Vesting of restricted stock units and performance share units		$ 2	(2)
Shares issued under employee stock purchase plan (in shares)		1,879,656
Shares issued under employee stock purchase plan	5,283		5,283				5,283
Tax withholdings related to net share settlements of stock-based compensation awards (in shares)		6,568,930
Tax withholdings related to net share settlements of stock-based compensation awards	(27,188)	$ (1)	(27,187)				(27,188)
Stock-based compensation on equity-classified awards	83,656		83,656				83,656
Repurchases of common stock (in shares)				(16,906,334)
Repurchases of common stock	(60,026)			$ (60,026)			(60,026)
Distributions to noncontrolling interest holders	(12,357)							(12,357)
Ending balance (in shares) at Dec. 31, 2017		748,541,862
Ending balance at Dec. 31, 2017	251,845	$ 75	2,174,708		(1,088,204)	31,844	250,973	872
Treasury stock, ending balance (in shares) at Dec. 31, 2017				(188,602,242)
Treasury stock, ending balance at Dec. 31, 2017				$ (867,450)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of change in accounting principle, net of tax					88,945		88,945
Cumulative effect of change in accounting principle, net of tax | Accounting Standards Update 2016-16 [Member]	88,945
Reclassification for impact of U.S. tax rate change	1,544				(161)	161
Comprehensive income (loss)	4,585				(11,079)	2,597	(8,482)	13,067
Exercise in stock options (in shares)		672,793
Exercise of stock options	81		81				81
Vesting of restricted stock units and performance share units (in shares)		14,264,895
Vesting of restricted stock units and performance share units		$ 1	(1)
Shares issued under employee stock purchase plan (in shares)		1,621,061
Shares issued under employee stock purchase plan	5,634		5,634				5,634
Shares issued to settle liability-classified awards (in shares)		1,240,379
Shares issued to settle liability-classified awards	6,436		6,436				6,436
Tax withholdings related to net share settlements of stock-based compensation awards (in shares)		(5,401,550)
Tax withholdings related to net share settlements of stock-based compensation awards	(22,709)		(22,709)				(22,709)
Stock-based compensation on equity-classified awards	70,411		70,411				70,411
Repurchases of common stock (in shares)				(3,252,886)
Repurchases of common stock	(10,041)			$ (10,041)			(10,041)
Distributions to noncontrolling interest holders	$ (12,576)							(12,576)
Ending balance (in shares) at Dec. 31, 2018	0	760,939,440
Ending balance at Dec. 31, 2018	$ 382,611	$ 76	2,234,560		(1,010,499)	34,602	381,248	1,363
Treasury stock, ending balance (in shares) at Dec. 31, 2018				(191,855,128)
Treasury stock, ending balance at Dec. 31, 2018	(877,491)			$ (877,491)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reclassification for impact of U.S. tax rate change	(3,443)
Comprehensive income (loss)	$ (7,216)				(22,377)	4,479	(17,898)	10,682
Exercise in stock options (in shares)	74,875	74,875
Exercise of stock options	$ 40		40				40
Vesting of restricted stock units and performance share units (in shares)		14,419,012
Vesting of restricted stock units and performance share units		$ 1	(1)
Shares issued under employee stock purchase plan (in shares)		1,486,006
Shares issued under employee stock purchase plan	4,083		4,083				4,083
Tax withholdings related to net share settlements of stock-based compensation awards (in shares)		(5,222,246)
Tax withholdings related to net share settlements of stock-based compensation awards	(17,413)		(17,413)				(17,413)
Stock-based compensation on equity-classified awards	89,051		89,051				89,051
Repurchases of common stock (in shares)				(14,027,227)
Repurchases of common stock	(45,175)			$ (45,175)			(45,175)
Distributions to noncontrolling interest holders	(10,935)							(10,935)
Ending balance (in shares) at Dec. 31, 2019		771,697,087
Ending balance at Dec. 31, 2019	395,046	$ 77	$ 2,310,320		$ (1,032,876)	$ 39,081	$ 393,936	$ 1,110
Treasury stock, ending balance (in shares) at Dec. 31, 2019				(205,882,355)
Treasury stock, ending balance at Dec. 31, 2019	$ (922,666)			$ (922,666)