Income (Loss) Per Share Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands		2 Months Ended	3 Months Ended																10 Months Ended	12 Months Ended
		Dec. 31, 2016	Dec. 31, 2017		Sep. 30, 2017		Jun. 30, 2017		Mar. 31, 2017		Dec. 31, 2016		Sep. 30, 2016		Jun. 30, 2016		Mar. 31, 2016		Oct. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Weighted Average Number Diluted Shares Outstanding Adjustment																				568,418,371
Earnings Per Share, Basic			$ (0.09)	[1],[2]	$ (0.00)	[1]	$ 0.02	[1]	$ 0.04	[1]	$ 0.09	[1]	$ 0.07	[1]	$ 0.10	[1]	$ 0.08	[1]		$ (0.03)	$ 0.34	$ (0.03)
Earnings Per Share, Basic and Diluted	[3]
Earnings Per Share, Basic [Abstract]
Income (loss) from continuing operations																			$ 28,601	$ 28,601	$ (166,209)	$ (73,247)
Net income attributable to noncontrolling interests																			12,587	$ 12,587	11,264	13,011
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest			$ (223)		$ (862)		$ (1,376)		$ 487		$ (10,749)		$ (1,345)		$ (2,963)		$ (2,057)					106,926
Net loss attributable to Groupon, Inc.			$ 47,721		$ 59		$ (9,326)		$ (24,414)		$ (52,588)		$ (37,976)		$ (54,904)		$ (49,119)		$ 16,014		$ (194,587)	$ 20,668
Basic, weighted average number of shares outstanding																			14,040,000	559,367,075	576,354,258	650,106,225
Earnings Per Share, Diluted [Abstract]
Basic, weighted average number of shares outstanding																			14,040,000	559,367,075	576,354,258	650,106,225
Earnings Per Share, Diluted			$ 0.08		$ 0.00		$ (0.02)		$ (0.04)		$ (0.09)		$ (0.07)		$ (0.10)		$ (0.08)			$ 0.02	$ (0.34)	$ 0.03
Common Class A [Member]
Income (Loss) from Continuing Operations, Per Basic and Diluted Share																			$ (0.28)			(0.13)
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic and Diluted Share																			(0.01)			0.16
Earnings Per Share, Basic and Diluted																			$ (0.29)			$ 0.03
Earnings Per Share, Basic [Abstract]
Income (loss) from continuing operations																			$ (151,284)			$ (72,977)
Net income attributable to noncontrolling interests																			9,559			12,963
Income (Loss) from Continuing Operations Attributable to Parent																			(160,843)			(85,940)
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest																			(7,152)	$ (1,974)		106,531
Net loss attributable to Groupon, Inc.																			$ (167,995)			$ 20,591
Basic, weighted average number of shares outstanding																			574,755,214	559,367,075		647,706,249
Earnings Per Share, Diluted [Abstract]
Basic, weighted average number of shares outstanding																			574,755,214	559,367,075		647,706,249
Common Class B [Member]
Income (Loss) from Continuing Operations, Per Basic and Diluted Share																			$ (0.28)			$ (0.13)
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic and Diluted Share																			(0.01)			0.16
Earnings Per Share, Basic and Diluted																			$ (0.29)			$ 0.03
Earnings Per Share, Basic [Abstract]
Income (loss) from continuing operations																			$ (632)			$ (270)
Net income attributable to noncontrolling interests																			40			48
Income (Loss) from Continuing Operations Attributable to Parent																			(672)			(318)
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest																			(30)			395
Net loss attributable to Groupon, Inc.																			$ (702)			$ 77
Basic, weighted average number of shares outstanding																			2,399,976			2,399,976
Earnings Per Share, Diluted [Abstract]
Basic, weighted average number of shares outstanding																			2,399,976			2,399,976
Employee Stock Option [Member]
Weighted Average Number Diluted Shares Outstanding Adjustment																				842,047
Restricted Stock [Member]
Weighted Average Number Diluted Shares Outstanding Adjustment																				488,773
Restricted Stock Units (RSUs) [Member]
Weighted Average Number Diluted Shares Outstanding Adjustment																				7,153,674
Employee Stock [Member]
Weighted Average Number Diluted Shares Outstanding Adjustment																				201,504
Performance Shares [Member]
Weighted Average Number Diluted Shares Outstanding Adjustment																				365,298
Common Stock [Member]
Earnings Per Share, Basic																				$ (0.03)
Income (Loss) from Continuing Operations, Per Basic and Diluted Share		$ (0.03)																			(0.31)
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic and Diluted Share		(0.02)																			(0.03)
Earnings Per Share, Basic and Diluted		$ (0.05)																			$ (0.34)
Earnings Per Share, Basic [Abstract]
Income (loss) from continuing operations		$ (14,293)																			$ (166,209)
Net income attributable to noncontrolling interests		1,665																			11,264
Income (Loss) from Continuing Operations Attributable to Parent		(15,958)																			(177,473)
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest		(9,932)																			(17,114)
Net loss attributable to Groupon, Inc.		$ (25,890)																			$ (194,587)
Basic, weighted average number of shares outstanding		574,884,987																			576,354,258
Earnings Per Share, Diluted [Abstract]
Basic, weighted average number of shares outstanding		574,884,987																			576,354,258
Earnings Per Share, Diluted																				0.02
Continuing Operations [Member] | Common Stock [Member]
Earnings Per Share, Basic																				(0.03)
Earnings Per Share, Diluted [Abstract]
Earnings Per Share, Diluted																				0.03
Discontinued Operations [Member] | Common Stock [Member]
Earnings Per Share, Basic																				(0.00)
Earnings Per Share, Diluted [Abstract]
Earnings Per Share, Diluted																				$ (0.01)

[1] The sum of per share amounts for quarterly periods may not equal year-to-date amounts due to rounding.

[2] t

[3] (1)The potentially dilutive impact