SEGMENT INFORMATION - Reconciliation of Adjusted EBITDA to Operating Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting, Other Significant Reconciling Item
Operating (loss) income	$ 17,885	$ 33,515	$ 23,262	$ (10,756)	$ (33,918)	$ (112,505)	$ (2,836)	$ 1,388	$ 63,906	$ (147,871)	$ 24,058
Stock-based compensation expense									97,078	149,230	8,916
Depreciation									24,310	14,543	8,419
Amortization of intangibles									62,212	23,261	3,153
Interest expense—third-party									(11,623)	(1,765)	0
Interest expense—related party									(118)	(5,971)	(894)
Other income (expense), net									17,859	1,974	(699)
Earnings (loss) before income taxes									70,024	(153,633)	22,465
Taxes									7,483	49,106	(11,834)
Net earnings (loss)									77,507	(104,527)	10,631
Net (earnings) loss attributable to noncontrolling interests									(189)	1,409	2,497
Net earnings (loss) attributable to ANGI Homeservices Inc. shareholders	$ 36,687	$ 26,617	$ 22,899	$ (8,885)	$ (58,224)	$ (71,761)	$ 254	$ 26,613	77,318	(103,118)	13,128
North America
Segment Reporting, Other Significant Reconciling Item
Operating (loss) income									78,102	(128,483)	32,464
Stock-based compensation expense									96,078	147,574	7,126
Depreciation									21,888	13,243	7,996
Amortization of intangibles									57,895	17,848	2,502
Adjusted EBITDA									253,963	50,182	50,088
Europe
Segment Reporting, Other Significant Reconciling Item
Operating (loss) income									(14,196)	(19,388)	(8,406)
Stock-based compensation expense									1,000	1,656	1,790
Depreciation									2,422	1,300	423
Amortization of intangibles									4,317	5,413	651
Adjusted EBITDA									$ (6,457)	$ (11,019)	$ (5,542)