Accrued Expenses and Other Short Term Liabilities - Schedule of Accrued Expenses and Other Short Term Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accrued Liabilities and Other Liabilities [Abstract]
Employees	$ 20,111	$ 17,748
Accrued expenses	12,725	9,507
Government authorities and other	18,196	14,006
Foreign exchange forward contract derivatives	3,646	0
Other short term liabilities	1,313	1,192
Total	$ 55,991	$ 42,453