Securities (Schedule of Contractual Maturities of Investment Securities Available for Sale) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012
Available-for-sale Securities [Abstract]
Due within one year, Amortized Cost	$ 23,144
Due after one year through five years, Amortized Cost	138,171
Due after five years through ten years, Amortized Cost	152,525
Due after ten years, Amortized Cost	581,285
No stated maturity date, Amortized Cost Basis	3,309
Total investment securities available-for-sale, Amortized Cost	898,434
Due within one year, Fair Value	26,360
Due after one year through five years, Fair Value	142,207
Due after five years through ten years, Fair Value	160,307
Due after ten years, Fair Value	611,341
No stated maturity date, Fair Value	3,409
Total investment securities available-for-sale, Fair Value	$ 943,624