Securities (Schedule Of Contractual Maturities) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Investment Holdings [Line Items]
Available-for-sale Securities, Amortized Cost	$ 829,558	$ 1,058,283
Available-for-sale Securities, Amortized Cost	829,558	1,058,283
Available-for-sale Securities, Estimated Fair Value	840,790	1,069,967
Available-for-sale Securities, Estimated Fair Value	840,790	1,069,967
Held-to-maturity Securities, Amortized Cost	1,552,699	1,718,023
Held-to-maturity Securities, Amortized Cost	1,552,699	1,718,023
Held-to-maturity Securities, Estimated Fair Value	1,571,524	1,741,846
Held-to-maturity securities, Estimated Fair Value	1,571,524	1,741,846
Debt Securities [Member]
Investment Holdings [Line Items]
Available-for-sale Securities, One year or less, Amortized Cost	200
Available-for-sale Securities, One year through five years, Amortized Cost	501,577
Available-for-sale Securities, Five years through ten years, Amortized Cost	54,150
Available-for-sale Securities, Ten years and thereafter, Amortized Cost	2,493
Available-for-sale Securities, Amortized Cost	558,420
Available-for-sale Securities, Amortized Cost	558,420
Available-for-sale Securities, One year or less, Estimated Fair Value	200
Available-for-sale Securities, One year through five years, Estimated Fair Value	497,891
Available-for-sale Securities, Five years through ten years, Estimated Fair Value	52,797
Available-for-sale Securities, Ten years and thereafter, Estimated Fair Value	2,296
Available-for-sale Securities, Estimated Fair Value	553,184
Available-for-sale Securities, Estimated Fair Value	553,184
Held-to-maturity Securities, One year or less, Amortized Cost	3,153
Held-to-maturity Securities, One year through five years, Amortized Cost	24,634
Held-to-maturity Securities, Five years through ten years, Amortized Cost	9,971
Held-to-maturity Securities, Ten years and thereafter, Amortized Cost	0
Held-to-maturity Securities, Amortized Cost	37,758
Held-to-maturity Securities, Amortized Cost	37,758
Held-to-maturity Securities, One year or less, Estimated Fair Value	3,178
Held-to-maturity Securities, One year through five years, Estimated Fair Value	25,215
Held-to-maturity Securities, Five years through ten years, Estimated Fair Value	9,995
Held-to-maturity Securities, Ten years and thereafter, Estimated Fair Value	0
Held-to-maturity Securities, Estimated Fair Value	38,388
Held-to-maturity securities, Estimated Fair Value	38,388
MBS [Member]
Investment Holdings [Line Items]
Available-for-sale Securities, Amortized Cost	271,138	345,263
Available-for-sale Securities, Amortized Cost	271,138	345,263
Available-for-sale Securities, Estimated Fair Value	287,606	363,964
Available-for-sale Securities, Estimated Fair Value	287,606	363,964
Held-to-maturity Securities, Amortized Cost	1,514,941	1,683,744
Held-to-maturity Securities, Amortized Cost	1,514,941	1,683,744
Held-to-maturity Securities, Estimated Fair Value	1,533,136	1,706,638
Held-to-maturity securities, Estimated Fair Value	$ 1,533,136	$ 1,706,638