Securities (Schedule of Contractual Maturities of Investment Securities Available for Sale) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014
Available-for-sale Securities [Abstract]
Due within one year, Amortized Cost	$ 12,863
Due after one year through five years, Amortized Cost	357,261
Due after five years through ten years, Amortized Cost	443,780
Due after ten years, Amortized Cost	790,596
No stated maturity date, Amortized Cost Basis	5,284
Total investment securities available-for-sale, Amortized Cost	1,609,784
Due within one year, Fair Value	12,945
Due after one year through five years, Fair Value	356,376
Due after five years through ten years, Fair Value	443,165
Due after ten years, Fair Value	793,779
No stated maturity date, Fair Value	5,146
Total investment securities available-for-sale, Fair Value	$ 1,611,411