COMMITMENTS, CONTINGENCIES AND REGULATORY MATTERS - Lease Activity (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Lessee, Lease, Description [Line Items]
Cash used in operating activities for amounts included in the measurement of lease liabilities	$ 3,078	$ 3,311
Short-term (twelve months or less) lease costs	481	1,205
Selling, general and administrative expense
Lessee, Lease, Description [Line Items]
Operating lease costs	2,092	2,281
Cost of revenue
Lessee, Lease, Description [Line Items]
Operating lease costs	$ 171	$ 634