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