Derivative Financial Instruments (Schedule Of Fair Values Of The Company's Derivative Instruments And The Line Items On The Consolidated Balance Sheets) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Gross Amounts of Recognized Assets	$ 1,799	$ 8,763
Gross Amounts of Recognized Liabilities	8,192	1,705
Prepaid Expenses And Other Current Assets [Member] | Derivatives Not Designated As Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Gross Amounts of Recognized Assets	1,314	5,873
Prepaid Expenses And Other Current Assets [Member] | Derivatives Designated As Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Gross Amounts of Recognized Assets	485	2,890
Other Current Liabilities [Member] | Derivatives Not Designated As Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Gross Amounts of Recognized Liabilities	7,128	1,002
Other Current Liabilities [Member] | Derivatives Designated As Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Gross Amounts of Recognized Liabilities	$ 1,064	$ 703