COMMITMENTS, CONTINGENCIES AND REGULATORY MATTERS - Lease Activity (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Lessee, Lease, Description [Line Items]
Cash used in operating activities for amounts included in the measurement of lease liabilities	$ 3,311	$ 4,737
Short-term (less than one year) lease costs	1,205	1,157
Selling, general and administrative expense
Lessee, Lease, Description [Line Items]
Operating lease costs	2,281	3,566
Cost of revenue
Lessee, Lease, Description [Line Items]
Operating lease costs	$ 634	$ 969