LEASES - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
LEASES
Operating lease costs	$ 2,052	$ 2,356	$ 4,218	$ 4,515
Finance lease costs:
Amortization of assets	4,784	2,959	9,507	5,650
Interest on lease liabilities	763	603	1,553	1,149
Total finance lease costs	5,547	3,562	11,060	6,799
Variable and short-term lease costs	284	212	411	773
Total lease costs	$ 7,883	$ 6,130	$ 15,689	$ 12,087