THE COMPANY AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) service_professional in Thousands, $ in Thousands, project in Millions	3 Months Ended
	Mar. 31, 2019 USD ($) operating_segment project service_professional service_category	Jan. 01, 2019 USD ($)
Entity Operations Information [Abstract]
Number of service categories | service_category	500
Number of service professionals (more than) | service_professional	250
Number of projects (more than) | project	20
Number of operating segments | operating_segment	2
Right of use assets	$ 91,650
Lease liability	$ 111,426
Accounting Standards Update 2016-02
Entity Operations Information [Abstract]
Right of use assets		$ 69,400
Lease liability		$ 69,400
ANGI Homeservices | Class B Common Stock | IAC
Entity Operations Information [Abstract]
Ownership interest (as a percent)	83.30%
Voting interest (as a percent)	98.00%