QUARTERLY RESULTS (UNAUDITED) - Summary (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								6 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	Jun. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Selected Quarterly Financial Information [Abstract]
Revenue	$ 321,508	$ 357,358	$ 343,896	$ 303,443	$ 278,992	$ 303,116	$ 294,822	$ 255,311		$ 1,326,205	$ 1,132,241	$ 736,386
Cost of revenue	12,448	13,312	10,722	10,011	13,426	14,015	14,703	13,595		46,493	55,739	34,073
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)
Net earnings	(95)	18,324	7,234	9,851	36,812	26,786	23,023	(9,114)
Net earnings 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)
Earnings (loss) per share attributable to ANGI Homeservices Inc. shareholders:
Basic (loss) earnings per share (USD per share)	$ 0.00	$ 0.04	$ 0.01	$ 0.02	$ 0.07	$ 0.06	$ 0.05	$ (0.02)		$ 0.07	$ 0.16	$ (0.24)
Diluted (loss) earnings per share (USD per share)	$ 0.00	$ 0.04	$ 0.01	$ 0.02	$ 0.07	$ 0.05	$ 0.05	$ (0.02)		$ 0.07	$ 0.15	$ (0.24)
Stock-based compensation expense										$ 68,255	$ 97,078	$ 149,230
Gain from the sale of a business										$ (218)	13,237	$ 0
Felix
Earnings (loss) per share attributable to ANGI Homeservices Inc. shareholders:
Gain from the sale of a business											13,200
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	$ 1,800	$ 1,800	$ 2,000	$ 2,300	$ 14,400	$ 12,300		$ 14,700	$ 12,800
Transaction costs							$ 1,900	4,000	$ 1,900
Write-off due to deferred revenue							$ 1,800	$ 2,800