SEGMENT INFORMATION - Financial Data by Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Segment Reporting Information [Line Items]
Revenue	$ 1,059,122	$ 767,387	$ 2,054,197	$ 1,528,220
Operating income (loss)	168,437	75,635	258,387	112,695
Operating segments | Match Group
Segment Reporting Information [Line Items]
Revenue	421,196	309,572	828,563	608,336
Operating income (loss)	150,165	82,975	262,398	141,846
Adjusted EBITDA	175,561	109,910	313,302	196,141
Operating segments | ANGI Homeservices
Segment Reporting Information [Line Items]
Revenue	294,822	180,711	550,133	331,456
Operating income (loss)	23,262	(4,141)	12,506	(2,753)
Adjusted EBITDA	66,979	13,666	103,619	23,878
Operating segments | Video
Segment Reporting Information [Line Items]
Revenue	62,757	55,182	128,919	105,759
Operating income (loss)	(14,982)	(7,829)	(30,857)	(23,418)
Adjusted EBITDA	(11,102)	(6,832)	(24,042)	(21,564)
Operating segments | Applications
Segment Reporting Information [Line Items]
Revenue	143,074	143,969	275,061	302,866
Operating income (loss)	33,077	39,134	58,538	71,902
Adjusted EBITDA	35,404	40,546	62,156	75,479
Operating segments | Publishing
Segment Reporting Information [Line Items]
Revenue	137,355	78,124	271,677	156,204
Operating income (loss)	12,807	(2,857)	28,618	(8,645)
Adjusted EBITDA	13,755	2,740	30,968	3,919
Operating segments | Other
Segment Reporting Information [Line Items]
Revenue				23,980
Operating income (loss)	0	0	0	(5,621)
Adjusted EBITDA	0	0	0	(1,532)
Inter-segment eliminations
Segment Reporting Information [Line Items]
Revenue	(82)	(171)	(156)	(381)
Corporate
Segment Reporting Information [Line Items]
Operating income (loss)	(35,892)	(31,647)	(72,816)	(60,616)
Adjusted EBITDA	$ (15,552)	$ (15,523)	$ (32,560)	$ (29,838)