QUARTERLY RESULTS (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Selected Quarterly Financial Information [Abstract]
Revenue	$ 223,213	$ 181,717	$ 180,711	$ 150,745	$ 123,668	$ 133,560	$ 130,173	$ 111,489	$ 736,386	$ 498,890	$ 361,201
Cost of revenue	11,682	7,999	7,562	6,830	6,293	6,826	6,745	5,994	34,073	25,858	22,936
Operating income (loss)	(33,918)	(112,505)	(2,836)	1,388	6,216	8,843	9,513	(514)	(147,871)	24,058	(1,568)
Net earnings (loss)	(58,231)	(72,158)	(25)	25,887	2,056	4,468	5,351	(1,244)
Net earnings (loss) attributable to ANGI Homeservices Inc. shareholders	$ (58,224)	$ (71,761)	$ 254	$ 26,613	$ 2,720	$ 5,075	$ 6,010	$ (677)	$ (103,118)	$ 13,128	$ (1,325)
(Loss) earnings per share attributable to ANGI Homeservices Inc. shareholders:
Basic (loss) earnings per share (USD per share)	$ (0.12)	$ (0.17)		$ 0.06	$ 0.01	$ 0.01	$ 0.01	$ 0.00	$ (0.24)	$ 0.03	$ 0.00
Diluted (loss) earnings per share (USD per share)	$ (0.12)	$ (0.17)		$ 0.06	$ 0.01	$ 0.01	$ 0.01	$ 0.00	$ (0.24)	$ 0.03	$ 0.00
Stock-based compensation expense									$ 149,230	$ 8,916	$ 7,853
HomeAdvisor
(Loss) earnings per share attributable to ANGI Homeservices Inc. shareholders:
Stock-based compensation expense	$ 15,600	$ 59,400
Angie's List
(Loss) earnings per share attributable to ANGI Homeservices Inc. shareholders:
Transaction costs	13,800	$ 17,000							$ 13,800
Write-off due to deferred revenue	$ 7,600