Securities (Amortized Cost And Estimated Fair Value Of Debt Securities) (Details) (USD $) In Thousands	Sep. 30, 2011
Securities [Abstract]
Held-to-Maturity Amortized Cost Basis, Due within one year	$ 3,531
Held-to-Maturity Amortized Cost Basis, Due after one year through five years	389
Held-to-Maturity Amortized Cost Basis, Mortgage-backed securities	442
Held-to-Maturity Amortized Cost Basis, Total	4,362
Held-to-Maturity Estimated Fair Value, Due within one year	3,561
Held-to-Maturity Estimated Fair Value, Due after one year through five years	403
Held-to-Maturity Estimated Fair Value, Mortgage-backed securities	460
Held-to-Maturity Estimated Fair Value, Total	4,424
Available-for-Sale Amortized Cost Basis, Due within one year	141,376
Available-for-Sale Amortized Cost Basis, Due after one year through five years	397,698
Available-for-Sale Amortized Cost Basis, Due after five years through ten years	399,787
Available-for-Sale Amortized Cost Basis, Due after ten years	27,198
Available-for-Sale Amortized Cost Basis, Mortgage-backed securities	679,894
Available-for-Sale Amortized Cost Basis, Total	1,645,953
Available-for-Sale Estimated Fair Value, Due within one year	143,935
Available-for-Sale Estimated Fair Value, Due after one year through five years	415,437
Available-for-Sale Estimated Fair Value, Due after five years through ten years	431,411
Available-for-Sale Estimated Fair Value, Due after ten years	28,840
Available-for-Sale Estimated Fair Value, Mortgage-backed securities	708,934
Available-for-Sale Estimated Fair Value, Total	$ 1,728,557