LEASES - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
LEASES
Operating lease costs	$ 1,934	$ 2,166
Finance lease costs:
Amortization of assets	4,014	4,723
Interest on lease liabilities	670	790
Total finance lease costs	4,684	5,513
Variable and short-term lease costs	583	127
Total lease costs	$ 7,201	$ 7,806