THE COMPANY AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) professional in Thousands, $ in Thousands, project in Millions	3 Months Ended
	Mar. 31, 2021 USD ($) professional category segment project	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($)
Noncontrolling Interest [Line Items]
Number of service categories | category	500
Number of service professionals (over) | professional	250
Number of projects (more than) | project	34
Number of operating segments | segment	2
Current deferred revenue	$ 57,675		$ 54,654
Noncurrent deferred revenue	100		200
Deferred revenue recognized during period	34,400	$ 37,100
Current capitalized sales commissions	49,200		49,600
Noncurrent capitalized sales commissions	48,700		500
Noncurrent capitalized sales commissions	$ 49,200		$ 400
Angi | Class B Common Stock | IAC
Noncontrolling Interest [Line Items]
Economic interest (as a percent)	84.20%
Voting interest (as a percent)	98.20%