OTHER NONOPERATING EXPENSE, NET (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Other Income and Expenses [Abstract]
Interest income	$ 110	$ 285	$ 189	$ 393
Foreign currency exchange gain / (loss), net	8,086	(3,002)	9,767	12,420
Change in fair value of derivatives (Note 11)	(1,100)	2,544	(732)	(11,506)
Other income / (expense), net	45	6	242	(58)
Total other non-operating income / (expense)	$ 7,141	$ (167)	$ 9,466	$ 1,249