LEASES - Components of Lease Expense (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 costs	$ 1,640	$ 2,355	$ 5,858	$ 6,870
Finance lease costs:
Amortization of assets	4,840	3,903	14,347	9,553
Interest on lease liabilities	789	671	2,342	1,820
Total finance lease costs	5,629	4,574	16,689	11,373
Variable and short-term lease costs	837	71	1,248	844
Total lease costs	$ 8,106	$ 7,000	$ 23,795	$ 19,087