REVENUE - Schedule of Components of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disaggregation of Revenue [Line Items]
Revenue	$ 35,235	$ 40,421	$ 74,696	$ 79,937
Service revenue
Disaggregation of Revenue [Line Items]
Revenue	33,173	37,638	70,244	75,401
Reimbursable expenses
Disaggregation of Revenue [Line Items]
Revenue	2,049	2,609	4,359	4,201
Non-controlling interests
Disaggregation of Revenue [Line Items]
Revenue	$ 13	$ 174	$ 93	$ 335