LEASES - Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
LEASES
Operating lease cost	$ 1,161	$ 1,223	$ 3,499	$ 3,548
Short-term lease cost	856	993	2,440	2,552
Variable lease cost	242	168	564	503
Finance leases:
Amortization of ROU assets	177	172	511	346
Interest on lease liabilities	9	13	34	43
Finance lease cost	186	185	545	389
Total lease cost	$ 2,445	$ 2,569	$ 7,048	$ 6,992