Derivatives and Hedge Accounting - Summary of Fair Value of Foreign Currency Exchange Contracts (Details) - Foreign currency exchange contracts - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Derivatives Designated as Hedging Instruments | Other current assets
Derivatives, Fair Value [Line Items]
Foreign currency exchange contracts, asset	$ 1,712	$ 10,892
Derivatives Designated as Hedging Instruments | Other assets
Derivatives, Fair Value [Line Items]
Foreign currency exchange contracts, asset	270	7,361
Derivatives Designated as Hedging Instruments | Accrued expense and other current liabilities
Derivatives, Fair Value [Line Items]
Foreign currency exchange contracts, liability	7,870	481
Derivatives Designated as Hedging Instruments | Other non-current liabilities
Derivatives, Fair Value [Line Items]
Foreign currency exchange contracts, liability	9,947	322
Derivatives not Designated as Hedging Instruments | Other current assets
Derivatives, Fair Value [Line Items]
Foreign currency exchange contracts, asset	216	46
Derivatives not Designated as Hedging Instruments | Accrued expense and other current liabilities
Derivatives, Fair Value [Line Items]
Foreign currency exchange contracts, liability	$ 0	$ 74