Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepayments to suppliers	$ 2,439	$ 2,774
Employee-related receivables	97	94
Taxes receivables	52,942	29,552
Other debtors	3,166	3,687
Prepaid expenses	13,638	9,475
Gross book value at end of period	72,282	45,582
Net book value at end of period	$ 72,282	$ 45,582