REVENUE - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Revenue	$ 178,453	$ 365,547
Revenue recognized when services are performed or assets are sold
Disaggregation of Revenue [Line Items]
Revenue	157,855	332,084
Revenue related to technology platforms and professional services
Disaggregation of Revenue [Line Items]
Revenue	14,043	17,178
Reimbursable expenses revenue
Disaggregation of Revenue [Line Items]
Revenue	$ 6,555	$ 16,285

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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+ Details