Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Other Liabilities Disclosure [Abstract]
Clients' prepayments	$ 9,176	$ 6,244
Employee-related payables	55,874	42,275
Other taxes	44,831	30,463
Accounts payable relating to capital expenditures	15,484	8,037
Other creditors	2,440	1,091
Deferred revenue	3,121	159
Total	$ 130,926	$ 88,269