Derivative Financial Instruments (Schedule Of The Fair Values Of Derivative Instruments) (Details) - Cash flow hedging - Foreign currency - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Derivatives Designated as Hedging Instruments | Prepaid expenses and other current assets
Asset Derivatives
Derivative assets fair value	$ 2,481	$ 460
Derivatives Designated as Hedging Instruments | Accrued expenses and other current liabilities
Liability Derivatives
Derivative liabilities fair value	110	3,816
Derivatives Not Designated as Hedging Instruments | Prepaid expenses and other current assets
Asset Derivatives
Derivative assets fair value	17	2,046
Derivatives Not Designated as Hedging Instruments | Accrued expenses and other current liabilities
Liability Derivatives
Derivative liabilities fair value	$ 704	$ 619