LEASE COST (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2019
Lease Cost Table Line Items
Total lease cost	$ 16,707	$ 31,032
Depreciation and Amortization [Member]
Lease Cost Table Line Items
Amortization of ROU assets - finance leases	1,798	3,405
Interest Expense
Lease Cost Table Line Items
Interest on lease liabilities - finance leases	32	40
Cost of Services
Lease Cost Table Line Items
Operating lease cost (cost resulting from lease payments)	12,647	23,346
Short-term Lease, Cost	1,247	2,312
Selling General And Administrative Expenses [Member]
Lease Cost Table Line Items
Operating lease cost (cost resulting from lease payments)	1,363	2,630
Sublease Income	(126)	(193)
Other income (expense), net
Lease Cost Table Line Items
Operating lease cost (cost resulting from lease payments)	242	484
Sublease Income	$ (496)	$ (992)

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- Definition

Amount of interest expense on finance lease liability.

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Amount of amortization expense attributable to right-of-use asset from finance lease.

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Amount of lease cost recognized by lessee for lease contract.

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Amount of single lease cost, calculated by allocation of remaining cost of lease over remaining lease term. Includes, but is not limited to, single lease cost, after impairment of right-of-use asset, calculated by amortization of remaining right-of-use asset and accretion of lease liability.

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