Derivatives - Additional Disclosures (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Derivative Instruments,Gain (Loss) [Line Items]
Net loss on foreign currency exchange contracts	$ 1,488	$ 218	$ 2,852	$ 894
Other income (expense), net | Not designated as hedging instrument | Foreign currency exchange contracts
Derivative Instruments,Gain (Loss) [Line Items]
Net loss on foreign currency exchange contracts	$ 1,500	$ 200	$ 2,900	$ 900