Financial Instruments - Schedule of Derivative Instruments on Consolidated Balance Sheets (Details) - Designated as Hedging Instrument - Level 2 - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Derivatives Fair Value [Line Items]
Asset Derivatives	$ 2,716	$ 2,359
Liability Derivatives	1,945	1,220
Foreign currency forward contracts | Other current assets
Derivatives Fair Value [Line Items]
Asset Derivatives	2,716	2,359
Foreign currency forward contracts | Accrued liabilities
Derivatives Fair Value [Line Items]
Liability Derivatives	$ 1,945	$ 1,220