LEASES - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Components of lease expense:
Operating lease cost	$ 5,423	$ 6,076	$ 17,256	$ 17,171
Finance lease cost:
Amortization of right-of-use assets	1,107	905	3,182	3,010
Interest on lease liabilities	343	356	1,030	1,073
Total finance lease cost	1,450	1,261	4,212	4,083
Short-term lease and variable lease costs	$ 3,353	$ 2,466	$ 8,925	$ 7,344