LEASE COMMITMENTS - 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
Components of lease expense:
Operating lease cost	$ 5,841	$ 5,437	$ 11,095	$ 11,441
Finance lease cost:
Amortization of right-of-use assets	906	1,004	2,105	1,876
Interest on lease liabilities	369	325	717	640
Total finance lease cost	1,275	1,329	2,822	2,516
Short-term lease and variable lease costs	$ 2,430	$ 2,328	$ 4,878	$ 4,270