Securities (Schedule Of Contractual Maturities) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Sep. 30, 2013
Securities [Abstract]
Available-for-sale Securities, One year or less, Amortized Cost	$ 201
Available-for-sale Securities, One year through five years, Amortized Cost	531,332
Available-for-sale Securities, Five years through ten years, Amortized Cost	142,417
Available-for-sale Securities, Ten years and thereafter, Amortized Cost	213,593
Available-for-sale Securities, Amortized Cost	887,543	1,058,283
Available-for-sale Securities, One year or less, Estimated Fair Value	204
Available-for-sale Securities, One year through five years, Estimated Fair Value	525,271
Available-for-sale Securities, Five years through ten years, Estimated Fair Value	146,593
Available-for-sale Securities, Ten years and thereafter, Estimated Fair Value	223,555
Available-for-sale Securities, Estimated Fair Value	895,623	1,069,967
Held-to-maturity Securities, One year or less, Amortized Cost	7,225
Held-to-maturity Securities, One year through five years, Amortized Cost	70,001
Held-to-maturity Securities, Five years through ten years, Amortized Cost	491,727
Held-to-maturity Securities, Ten years and thereafter, Amortized Cost	1,151,330
Held-to-maturity Securities, Amortized Cost	1,720,283	1,718,023
Held-to-maturity Securities, One year or less, Estimated Fair Value	7,296
Held-to-maturity Securities, One year through five years, Estimated Fair Value	73,335
Held-to-maturity Securities, Five years through ten years, Estimated Fair Value	490,835
Held-to-maturity Securities, Ten years and thereafter, Estimated Fair Value	1,163,618
Held-to-maturity Securities, Estimated Fair Value	$ 1,735,084	$ 1,741,846