Income (Loss) Per Share Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016		Sep. 30, 2017	Sep. 30, 2016
Weighted Average Number Diluted Shares Outstanding Adjustment		9,448,009			0
Basic net income (loss) per share
Allocation of net loss - continuing operations		$ 3,802	$ (34,447)		$ (22,470)	$ (126,754)
Less: Allocation of net income attributable to noncontrolling interests		2,881	2,184		9,460	8,880
Net loss from discontinued operations		(862)	(1,345)		(1,751)	(6,365)
Net loss attributable to Groupon, Inc.		$ 59	$ (37,976)		$ (33,681)	$ (141,999)
Basic, weighted average number of shares outstanding	[1]	557,221,040	575,216,191		559,726,154	578,290,291
Diluted net income (loss) per share
Basic, weighted average number of shares outstanding	[1]	557,221,040	575,216,191		559,726,154	578,290,291
Diluted, weighted average number of shares outstanding	[1]	566,669,049	575,216,191		559,726,154	578,290,291
Common Class A [Member]
Income (Loss) from Continuing Operations, Per Basic and Diluted Share	[2]	$ 0.00	$ (0.06)	[3]	$ (0.06)	$ (0.23)	[3]
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic and Diluted Share	[2]	0.00	(0.01)	[3]	0.00	(0.02)	[3]
Earnings Per Share, Basic and Diluted	[2]	$ 0.00	$ (0.07)	[3]	$ (0.06)	$ (0.25)	[3]
Basic net income (loss) per share
Allocation of net loss - continuing operations		$ 3,802	$ (34,303)		$ (22,470)	$ (126,228)
Less: Allocation of net income attributable to noncontrolling interests		2,881	2,175		9,460	8,843
Allocation of net loss attributable to common stockholders - continuing operations		921	(36,478)		(31,930)	(135,071)
Net loss from discontinued operations		(862)	(1,340)		(1,751)	(6,339)
Net loss attributable to Groupon, Inc.		$ 59	$ (37,818)		$ (33,681)	$ (141,410)
Basic, weighted average number of shares outstanding		557,221,040	572,816,215		559,726,154	575,890,315
Diluted net income (loss) per share
Basic, weighted average number of shares outstanding		557,221,040	572,816,215		559,726,154	575,890,315
Common Class B [Member]
Income (Loss) from Continuing Operations, Per Basic and Diluted Share	[3]		$ (0.06)			$ (0.23)
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic and Diluted Share	[3]		(0.01)			(0.02)
Earnings Per Share, Basic and Diluted	[3]		$ (0.07)			$ (0.25)
Basic net income (loss) per share
Allocation of net loss - continuing operations			$ (144)			$ (526)
Less: Allocation of net income attributable to noncontrolling interests			9			37
Allocation of net loss attributable to common stockholders - continuing operations			(153)			(563)
Net loss from discontinued operations			(5)			(26)
Net loss attributable to Groupon, Inc.			$ (158)			$ (589)
Basic, weighted average number of shares outstanding			2,399,976			2,399,976
Diluted net income (loss) per share
Basic, weighted average number of shares outstanding			2,399,976			2,399,976

[1] (1)The structure of the Company's common stock changed during the year ended December 31, 2016. Refer to Note 8, Stockholders' Equity and Compensation Arrangements, and Note 12, Income (Loss) per Share, for additional information.

[2] Three Months Ended September 30, 2017 Nine Months Ended September 30, 2017Basic and diluted net income (loss) per share: Numerator Net income (loss) - continuing operations $3,802 $(22,470)Less: Net income (loss) attributable to noncontrolling interests 2,881 9,460Net income (loss) attributable to common stockholders - continuing operations $921 $(31,930)Net income (loss) attributable to common stockholders - discontinued operations (862) (1,751)Net income (loss) attributable to common stockholders $59 $(33,681)Denominator Shares used in computation of basic net income (loss) per share 557,221,040 559,726,154Weighted-average effect of dilutive securities 9,448,009 —Shares used in computation of diluted net income (loss) per share 566,669,049 559,726,154Basic and diluted net income (loss) per share (1): Continuing operations $0.00 $(0.06)Discontinued operations (0.00) (0.00)Basic and diluted net income (loss) per share $0.00 $(0.06)(1)The potentially dilutive impact of the warrants and the convertible senior notes has been excluded from the calculation of diluted net income (loss) per share for the three and nine months ended September 30, 2017 as the effect on net income (loss) per share from continuing operations was antidilutive. The potentially dilutive impact of equity awards has also been excluded from the calculation of diluted net income (loss) per share for the nine months ended September 30, 2017 as the effect on net income (loss) per share from continuing operations was antidilutive.

[3] (1)The potentially dilutive impacts of a conversion of Class B to Class A shares, outstanding equity awards, warrants and convertible senior notes have been excluded from the calculation of diluted net income (loss) per share for the three and nine months ended September 30, 2016 as their effect on net income (loss) per share from continuing operations was antidilutive.