LEASE COST (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Lease Cost Table Line Items
Total lease cost	$ 15,113	$ 14,325
Depreciation and Amortization
Lease Cost Table Line Items
Amortization of ROU assets - finance leases	1,916	1,607
Interest Expense
Lease Cost Table Line Items
Interest on lease liabilities - finance leases	56	8
Cost of Services
Lease Cost Table Line Items
Operating lease cost (cost resulting from lease payments)	12,038	10,699
Short-term Lease, Cost	997	1,065
Selling General And Administrative Expenses
Lease Cost Table Line Items
Operating lease cost (cost resulting from lease payments)	542	1,267
Sublease Income	(182)	(67)
Other income (expense), net
Lease Cost Table Line Items
Operating lease cost (cost resulting from lease payments)	242	242
Sublease Income	$ (496)	$ (496)