SEGMENT INFORMATION - Reconciliation of Adjusted EBITDA to Operating Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting, Other Significant Reconciling Item
Operating loss	$ 33,515	$ (112,505)	$ 46,021	$ (113,953)
Stock-based compensation expense	22,474	103,980	69,433	120,280
Depreciation	6,100	3,491	18,170	9,705
Amortization of intangibles	15,611	2,768	47,695	6,885
Interest expense—third party	(3,132)	0	(8,797)	0
Interest expense—related party	(23)	(1,864)	(102)	(5,538)
Other income, net	1,566	1,364	2,975	2,100
Earnings (loss) before income taxes	31,926	(113,005)	40,097	(117,391)
Income tax (provision) benefit	(5,140)	40,847	598	71,095
Net earnings (loss)	26,786	(72,158)	40,695	(46,296)
Net (earnings) loss attributable to noncontrolling interests	(169)	397	(64)	1,402
Net earnings (loss) attributable to ANGI Homeservices Inc. shareholders	26,617	(71,761)	40,631	(44,894)
North America
Segment Reporting, Other Significant Reconciling Item
Operating loss	36,117	(107,687)	56,862	(99,479)
Stock-based compensation expense	22,256	103,565	68,652	118,961
Depreciation	5,563	3,085	16,491	8,862
Amortization of intangibles	14,677	1,097	44,301	3,012
Adjusted EBITDA	78,613	60	186,306	31,356
Europe
Segment Reporting, Other Significant Reconciling Item
Operating loss	(2,602)	(4,818)	(10,841)	(14,474)
Stock-based compensation expense	218	415	781	1,319
Depreciation	537	406	1,679	843
Amortization of intangibles	934	1,671	3,394	3,873
Adjusted EBITDA	$ (913)	$ (2,326)	$ (4,987)	$ (8,439)