FAIR VALUE MEASUREMENTS (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 106,611	$ 112,653
Restricted cash	69,638	59,703
Current maturities of long-term debt	0	(3,375)
Long-term debt	(972,285)	(1,022,004)
Carrying Amount | Interest rate swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps	36,727	15,440
Carrying Amount | Foreign currency exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contracts, liabilities	(118)
Foreign currency contracts, assets		2,807
Carrying Amount | Foreign currency option contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contracts, liabilities	(35)
Foreign currency contracts, assets		352
Fair Value | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	106,611	112,653
Restricted cash	69,638	59,703
Current maturities of long-term debt	0	0
Long-term debt	0	0
Fair Value | Level 1 | Interest rate swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps	0	0
Fair Value | Level 1 | Foreign currency exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contracts, liabilities	0
Foreign currency contracts, assets		0
Fair Value | Level 1 | Foreign currency option contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contracts, liabilities	0
Foreign currency contracts, assets		0
Fair Value | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Restricted cash	0	0
Current maturities of long-term debt	0	(3,375)
Long-term debt	(973,505)	(1,030,135)
Fair Value | Level 2 | Interest rate swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps	36,727	15,440
Fair Value | Level 2 | Foreign currency exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contracts, liabilities	(118)
Foreign currency contracts, assets		2,807
Fair Value | Level 2 | Foreign currency option contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contracts, liabilities	$ (35)
Foreign currency contracts, assets		$ 352