LEASES - Lease Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Lessee, Lease, Description [Line Items]
Fixed lease cost	$ 25,712	$ 19,627
Variable lease cost	4,135	4,748
Net lease cost	29,847	24,375
Short-term lease cost	100	40
Sublease Income	1,800	1,800
Cost of revenue
Lessee, Lease, Description [Line Items]
Fixed lease cost	346	321
Variable lease cost	0	0
Selling and marketing expense
Lessee, Lease, Description [Line Items]
Fixed lease cost	7,305	9,913
Variable lease cost	1,087	2,314
General and administrative expense
Lessee, Lease, Description [Line Items]
Fixed lease cost	16,829	7,545
Variable lease cost	2,481	1,567
Product development expense
Lessee, Lease, Description [Line Items]
Fixed lease cost	1,232	1,848
Variable lease cost	$ 567	$ 867