Securities (Schedule of Contractual Maturities of Investment Securities Available for Sale) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013
Available-for-sale Securities [Abstract]
Due within one year, Amortized Cost	$ 23,249
Due after one year through five years, Amortized Cost	278,538
Due after five years through ten years, Amortized Cost	463,423
Due after ten years, Amortized Cost	802,034
No stated maturity date, Amortized Cost Basis	5,279
Total investment securities available-for-sale, Amortized Cost	1,572,523
Due within one year, Fair Value	23,493
Due after one year through five years, Fair Value	278,715
Due after five years through ten years, Fair Value	459,080
Due after ten years, Fair Value	803,223
No stated maturity date, Fair Value	5,140
Total investment securities available-for-sale, Fair Value	$ 1,569,651