LEASES - Summary of operating lease cost and other operating lease information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Lease Costs
Fixed lease costs	$ 11,976	$ 10,055	$ 6,225
Variable lease costs	1,722	2,096	1,651
Total	13,698	12,151	7,876
Cash paid for operating lease liabilities, net of lease incentive	12,709	14,347	7,346
Right-of-use assets recorded in exchange for lease obligations	$ 8,692	$ 42,191	$ 41,605
Weighted average remaining lease term	7 years 9 months 7 days	9 years 2 months 4 days
Weighted average discount rate	6.96%	6.87%