LEASE COMMITMENTS - Components of Lease Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Components of lease expense:
Operating lease cost	$ 23,968	$ 23,410
Finance lease cost:
Amortization of right-of-use assets	3,982	4,217
Interest on lease liabilities	1,414	1,353
Total finance lease cost	5,396	5,570
Short-term lease and variable lease costs	$ 9,421	$ 8,629