Investment Securities (Amortized Cost And Fair Value Of Investment Securities By Contractual Maturities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011
Investment Securities [Abstract]
Amortized Cost of Securities Available-for-Sale, Due in one year or less	$ 17,983
Fair Value of Securities Available-for-Sale, Due in one year or less	17,915
Amortized Cost of Securities Held-to-Maturity, Due in one year or less	99,966
Fair Value of Securities Held-to-Maturity, Due in one year or less	101,372
Amortized Cost of Securities Available-for-Sale, Due after one year through five years	125,416
Fair Value of Securities Available-for-Sale, Due after one year through five years	123,651
Amortized Cost of Securities Available-for-Sale, Due after five years through ten years	858,217
Fair Value of Securities Available-for-Sale, Due after five years through ten years	835,179
Amortized Cost of Securities Held-to-Maturity, Due after five years through ten years	29,709
Fair Value of Securities Held-to-Maturity, Due after five years through ten years	30,943
Amortized Cost of Securities Available-for-Sale, Due after ten years	307,905	[1]
Fair Value of Securities Available-for-Sale, Due after ten years	317,733	[1]
Amortized Cost of Securities Held-to-Maturity, Due after ten years	1,023,829	[1]
Fair Value of Securities Held-to-Maturity, Due after ten years	1,071,662	[1]
Amortized Cost of Securities Available-for-Sale, Total	1,309,521
Fair Value of Securities Available-for-Sale, Total	1,294,478
Amortized Cost of Securities Held-to-Maturity, Total	1,153,504
Fair Value of Securities Held-to-Maturity, Total	$ 1,203,977

[1] Equity securities are reported in this category