Other Income (Expense), Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other Income and Expenses [Abstract]
Net gain (loss) on foreign currency exchange contracts	$ (3,603)	$ (1,251)	$ 294
Net gain (loss) on foreign currency exchange transactions	2,174	1,911	(522)
Other income	581	180	221
Other income (expense), net	$ (848)	$ 840	$ (7)