LEASES - Components of Lease Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
LEASES
Operating lease costs	$ 8,069	$ 9,185
Finance lease costs:
Amortization of assets	20,555	13,711
Interest on lease liabilities	3,264	2,521
Total finance lease costs	23,819	16,232
Variable and short-term lease costs	2,066	989
Total lease costs	$ 33,954	$ 26,406