SEGMENT INFORMATION - Reconciliation of Adjusted EBITDA to Operating Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting, Other Significant Reconciling Item
Operating (loss) income	$ 6,157	$ 24,726	$ 11,403	$ (3,641)	$ 17,885	$ 33,515	$ 23,262	$ (10,756)	$ 38,645	$ 63,906	$ (147,871)
Stock-based compensation expense									68,255	97,078	149,230
Depreciation									39,915	24,310	14,543
Amortization of intangibles									55,482	62,212	23,261
Interest expense—third-party									11,493	11,623	1,765
Interest expense—related party									(16)	(118)	(5,971)
Other income, net									6,510	17,859	1,974
Earnings (loss) before income taxes									33,646	70,024	(153,633)
Taxes									1,668	7,483	49,106
Net earnings (loss)									35,314	77,507	(104,527)
Net earnings attributable to noncontrolling interests									485	189	(1,409)
Net earnings (loss) attributable to ANGI Homeservices Inc. shareholders	$ (107)	$ 17,999	$ 6,968	$ 9,969	$ 36,687	$ 26,617	$ 22,899	$ (8,885)	34,829	77,318	(103,118)
North America
Segment Reporting, Other Significant Reconciling Item
Operating (loss) income									48,967	78,102	(128,483)
Stock-based compensation expense									67,646	96,078	147,574
Depreciation									37,481	21,888	13,243
Amortization of intangibles									54,098	57,895	17,848
Adjusted EBITDA									208,192	253,963	50,182
Europe
Segment Reporting, Other Significant Reconciling Item
Operating (loss) income									(10,322)	(14,196)	(19,388)
Stock-based compensation expense									609	1,000	1,656
Depreciation									2,434	2,422	1,300
Amortization of intangibles									1,384	4,317	5,413
Adjusted EBITDA									$ (5,895)	$ (6,457)	$ (11,019)