LEASES - Lease Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Finance lease cost
Amortization of right-of-use-assets	$ 13,295	$ 13,671	$ 13,805
Interest on lease liabilities	2,344	2,565	2,546
Operating lease cost	92,227	94,039	87,741
Short-term lease and other	8,432	10,963	10,017
Variable lease cost	13,325	12,459	9,888
Sublease income	(27,223)	(22,385)	(23,261)
Total lease cost	$ 102,400	$ 111,312	$ 100,736