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]
Foreign Currency Transaction Gain (loss), net	$ 7,238	$ (3,835)	$ (5,114)
Foreign Currency Contract Gain (Loss), Net	(5,358)	4,154	4,904
Other	144	(440)	122
Total	$ 2,024	$ (121)	$ (88)