SEGMENT INFORMATION - Capital Expenditures by Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Capital expenditures:	$ 136,652	$ 85,634	$ 75,523
Operating Segments | Match Group
Segment Reporting Information [Line Items]
Capital expenditures:	38,754	30,954	28,833
Operating Segments | ANGI Homeservices
Segment Reporting Information [Line Items]
Capital expenditures:	68,804	46,976	26,837
Operating Segments | Vimeo
Segment Reporting Information [Line Items]
Capital expenditures:	2,801	209	109
Operating Segments | Dotdash
Segment Reporting Information [Line Items]
Capital expenditures:		102	825
Operating Segments | Applications
Segment Reporting Information [Line Items]
Capital expenditures:	85	111	227
Operating Segments | Emerging & Other
Segment Reporting Information [Line Items]
Capital expenditures:	345	1,119	852
Corporate
Segment Reporting Information [Line Items]
Capital expenditures:	$ 25,863	$ 6,163	$ 17,840