SEGMENT INFORMATION - Financial Data by Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information [Line Items]
Revenue	$ 995,075	$ 760,833
Operating income (loss)	89,950	37,060
Adjusted EBITDA	188,398	101,976
Operating segments | Match Group
Segment Reporting Information [Line Items]
Revenue	407,367	298,764
Operating income (loss)	112,233	58,871
Adjusted EBITDA	137,741	86,231
Operating segments | ANGI Homeservices
Segment Reporting Information [Line Items]
Revenue	255,311	150,745
Operating income (loss)	(10,756)	1,388
Adjusted EBITDA	36,640	10,212
Operating segments | Video
Segment Reporting Information [Line Items]
Revenue	66,162	50,577
Operating income (loss)	(15,875)	(15,589)
Adjusted EBITDA	(12,940)	(14,732)
Operating segments | Applications
Segment Reporting Information [Line Items]
Revenue	131,987	158,897
Operating income (loss)	25,461	32,768
Adjusted EBITDA	26,752	34,933
Operating segments | Publishing
Segment Reporting Information [Line Items]
Revenue	134,322	78,080
Operating income (loss)	15,811	(5,788)
Adjusted EBITDA	17,213	1,179
Operating segments | Other
Segment Reporting Information [Line Items]
Revenue		23,980
Operating income (loss)	0	(5,621)
Adjusted EBITDA	0	(1,532)
Inter-segment eliminations
Segment Reporting Information [Line Items]
Revenue	(74)	(210)
Corporate
Segment Reporting Information [Line Items]
Operating income (loss)	(36,924)	(28,969)
Adjusted EBITDA	$ (17,008)	$ (14,315)