OPERATING LEASES - Lease Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Lease costs
Operating lease cost	$ 1,980	$ 1,876
Short-term lease cost	40	61
Sublease income	(378)	(153)
Total lease cost	$ 1,642	$ 1,784