(LOSS) EARNINGS PER SHARE - COMPUTATION OF BASIC AND DILUTED EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ 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
Earnings Per Share [Abstract]
Net (loss) earnings									$ (104,527)	$ 10,631	$ (3,996)
Net loss attributable to noncontrolling interests									1,409	2,497	2,671
Net (loss) earnings 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)
Weighted average basic shares outstanding (shares)									430,612	414,754	414,754
Dilutive securities including stock appreciation rights, stock options, RSUs and subsidiary denominated equity awards (shares)									0	0	0
Weighted average diluted shares outstanding (shares)									430,612	414,754	414,754
(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
Potentially dilutive securities excluded from calculation of diluted earnings per share (shares)									54,100