Derivative Instruments And Hedging Activities - Derivative Instruments Designated As Hedging Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Asset derivative instruments designated as hedging instruments	$ 1,617	$ 966
Liability derivative instruments designated as hedging instruments	8,757	12,467
Other Current Assets | Interest Rate Swaps
Derivatives, Fair Value [Line Items]
Asset derivative instruments designated as hedging instruments	875	311
Other Assets, Net | Interest Rate Swaps
Derivatives, Fair Value [Line Items]
Asset derivative instruments designated as hedging instruments	742	655
Accrued Liabilities | Foreign Exchange Contracts
Derivatives, Fair Value [Line Items]
Liability derivative instruments designated as hedging instruments	7,170	7,492
Other Noncurrent Liabilities | Foreign Exchange Contracts
Derivatives, Fair Value [Line Items]
Liability derivative instruments designated as hedging instruments	$ 1,587	$ 4,975