SEGMENT INFORMATION - Capital Expenditures by Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Capital expenditures	$ 85,634	$ 75,523	$ 78,039
Operating Segments | Match Group
Segment Reporting Information [Line Items]
Capital expenditures	30,954	28,833	46,098
Operating Segments | ANGI Homeservices
Segment Reporting Information [Line Items]
Capital expenditures	46,976	26,837	16,660
Operating Segments | Vimeo
Segment Reporting Information [Line Items]
Capital expenditures	209	109	1,959
Operating Segments | Dotdash
Segment Reporting Information [Line Items]
Capital expenditures	102	825	1,671
Operating Segments | Applications
Segment Reporting Information [Line Items]
Capital expenditures	111	227	1,196
Operating Segments | Emerging & Other
Segment Reporting Information [Line Items]
Capital expenditures	1,119	852	6,683
Corporate
Segment Reporting Information [Line Items]
Capital expenditures	$ 6,163	$ 17,840	$ 3,772