Investment Securities, Available-for-sale Securities, Maturities (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014
Amortized Cost [Abstract]
Due in one year or less	$ 2,195
Due in one year through five years	512,543
Due after five years through ten years	220,164
Due after ten years	520
Amortized Cost	735,422
Fair Value [Abstract]
Due in one year or less	2,210
Due in one year through five years	507,031
Due after five years through ten years	212,822
Due after ten years	525
Fair Value	$ 722,588