Derivative Financial Instruments (Schedule Of Derivatives, Location In Consolidated Balance Sheets) (Details) (Interest Rate Swap Contracts [Member], Derivatives Designated As Hedging Instruments [Member], USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Derivatives, Fair Value [Line Items]
Derivatives Designated as Hedging, Liability	$ 98,938	$ 108,090
Current Portion Of Other Long-Term Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivatives Designated as Hedging, Liability	23,591	23,117
Other Long-Term Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivatives Designated as Hedging, Liability	$ 75,347	$ 84,973