SEGMENT INFORMATION - Financial Data by Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Revenue	$ 1,228,765	$ 1,105,843
Operating income (loss)	(177,780)	79,873
Operating segments | Match Group
Segment Reporting Information [Line Items]
Revenue	544,642	464,625
Operating income (loss)	134,681	118,828
Adjusted EBITDA	171,502	155,067
Operating segments | ANGI Homeservices
Segment Reporting Information [Line Items]
Revenue	343,650	303,443
Operating income (loss)	(16,296)	(3,641)
Adjusted EBITDA	34,397	37,179
Operating segments | Vimeo
Segment Reporting Information [Line Items]
Revenue	56,968	43,581
Operating income (loss)	(14,589)	(17,784)
Adjusted EBITDA	(11,408)	(16,200)
Operating segments | Dotdash
Segment Reporting Information [Line Items]
Revenue	44,120	33,961
Operating income (loss)	2,411	3,047
Adjusted EBITDA	7,011	7,150
Operating segments | Applications
Segment Reporting Information [Line Items]
Revenue	104,148	143,549
Operating income (loss)	(218,588)	25,356
Adjusted EBITDA	10,151	29,688
Operating segments | Emerging & Other
Segment Reporting Information [Line Items]
Revenue	135,305	116,748
Operating income (loss)	(19,845)	(2,520)
Adjusted EBITDA	(16,980)	(2,095)
Inter-segment eliminations
Segment Reporting Information [Line Items]
Revenue	(68)	(64)
Corporate
Segment Reporting Information [Line Items]
Operating income (loss)	(45,554)	(43,413)
Adjusted EBITDA	$ (31,398)	$ (20,220)