Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Payroll and related liabilities	$ 30,225	$ 24,429
Advances from employees	796	572
Other accrued expenses	27,911	20,518
Total	$ 58,932	$ 45,519