Fair Value Of Financial Instruments (Schedule Of Carrying Amounts And Estimated Fair Values Of Financial Instruments) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Assets:
AFS securities	$ 840,790	$ 1,069,967
HTM securities	1,571,524	1,741,846
Carrying Amount [Member]
Assets:
Cash and cash equivalents	810,840	113,886
AFS securities	840,790	1,069,967
HTM securities	1,552,699	1,718,023
Loans receivable	6,233,170	5,958,868
FHLB stock	213,054	128,530
Liabilities:
Deposits	4,655,272	4,611,446
FHLB borrowings	3,369,677	2,513,538
Repurchase agreements	220,000	320,000
Estimated Fair Value [Member]
Assets:
Cash and cash equivalents	810,840	113,886
AFS securities	840,790	1,069,967
HTM securities	1,571,524	1,741,846
Loans receivable	6,429,840	6,132,239
FHLB stock	213,054	128,530
Liabilities:
Deposits	4,674,268	4,646,263
FHLB borrowings	3,423,547	2,599,749
Repurchase agreements	$ 227,539	$ 333,749