Derivative Financial Instruments (Schedule Of Fair Value Of Derivative Financial Instruments) (Details) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Total derivative assets	$ 47,209	$ 33,421
Total derivative liabilities	39,599	29,060
Designated As Hedging Instrument [Member]
Total derivative assets	8,096	4,766
Designated As Hedging Instrument [Member] | Other Assets [Member]
Total derivative assets	8,096	4,766
Derivatives Not Designated As Hedging Instruments [Member]
Total derivative assets	39,113	28,655
Total derivative liabilities	39,599	29,060
Derivatives Not Designated As Hedging Instruments [Member] | Other Assets [Member] | Interest Rate Contracts [Member]
Total derivative assets	38,927	28,269
Derivatives Not Designated As Hedging Instruments [Member] | Other Assets [Member] | Commodity Contracts [Member]
Total derivative assets	0	132
Derivatives Not Designated As Hedging Instruments [Member] | Other Assets [Member] | Mortgage Contracts [Member]
Total derivative assets	186	254
Derivatives Not Designated As Hedging Instruments [Member] | Other Liabilities [Member] | Interest Rate Contracts [Member]
Total derivative liabilities	39,599	28,928
Derivatives Not Designated As Hedging Instruments [Member] | Other Liabilities [Member] | Commodity Contracts [Member]
Total derivative liabilities	$ 0	$ 132