FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS (Details) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jan. 31, 2017 contracts	Dec. 31, 2016 USD ($)	Nov. 10, 2015 contracts	Nov. 14, 2014 contracts
Fair Value, By Balance Sheet Grouping Disclosure Information [Line Items]
Accumulated other comprehensive loss		$ (209,249)		$ (209,249)			$ (243,988)
Unrealized gain / (loss) on derivative instruments (Note 12)		(40)	$ (2,973)	1,218	$ (4,221)
Forward Contracts [Member]
Fair Value, By Balance Sheet Grouping Disclosure Information [Line Items]
Derivative, Number of Instruments Held | contracts						1
Interest rate swap [Member]
Fair Value, By Balance Sheet Grouping Disclosure Information [Line Items]
Derivative, Number of Instruments Held | contracts								3	2
Accumulated other comprehensive loss		(3,233)		(3,233)			$ (4,451)
Unrealized gain / (loss) on derivative instruments (Note 12)				178
Fair Value, Inputs, Level 2 [Member] | Currency Swap [Member]
Fair Value, By Balance Sheet Grouping Disclosure Information [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net		$ (1,100)	$ 2,544	(732)	$ (11,506)
Interest Expense [Member] | Interest rate swap [Member]
Fair Value, By Balance Sheet Grouping Disclosure Information [Line Items]
Derivative Instruments, Loss Reclassified from Accumulated OCI into Income, Effective Portion	[1]			$ 1,396

[1] (2) Amounts reclassified from accumulated other comprehensive loss during the six months ended June 30, 2017 were reclassified to interest expense