QUARTERLY RESULTS (UNAUDITED) - Summary (Details) - USD ($) $ / shares in Units, $ 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
Selected Quarterly Financial Information [Abstract]
Revenue	$ 278,992	$ 303,116	$ 294,822	$ 255,311	$ 223,213	$ 181,717	$ 180,711	$ 150,745	$ 1,132,241	$ 736,386	$ 498,890
Cost of revenue	13,426	14,015	14,703	13,595	11,682	7,999	7,562	6,830	55,739	34,073	25,858
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
Net (loss) earnings	36,812	26,786	23,023	(9,114)	(58,231)	(72,158)	(25)	25,887	77,507
Net (loss) earnings 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
Earnings (loss) per share attributable to ANGI Homeservices Inc. shareholders:
Basic (loss) earnings per share (USD per share)	$ 0.07	$ 0.06	$ 0.05	$ (0.02)	$ (0.12)	$ (0.17)		$ 0.06	$ 0.16	$ (0.24)	$ 0.03
Diluted (loss) earnings per share (USD per share)	$ 0.07	$ 0.05	$ 0.05	$ (0.02)	$ (0.12)	$ (0.17)		$ 0.06	$ 0.15	$ (0.24)	$ 0.03
Stock-based compensation expense									$ 97,078	$ 149,230	$ 8,916
Gain from the sale of a business									$ 13,237	0	$ 0
Felix | Disposal Group, Disposed of by Sale
Earnings (loss) per share attributable to ANGI Homeservices Inc. shareholders:
Gain from the sale of a business	$ 10,000
HomeAdvisor
Earnings (loss) per share attributable to ANGI Homeservices Inc. shareholders:
Stock-based compensation expense	14,400	$ 12,300	$ 12,800	$ 14,700	$ 15,600	$ 59,400
Angie's List
Earnings (loss) per share attributable to ANGI Homeservices Inc. shareholders:
Transaction costs		$ 17,000	1,900	4,000	$ 13,800					$ 13,800
Write-off due to deferred revenue	$ 7,600		$ 1,800	$ 2,800