Loans Receivable And Allowance For Credit Losses (Summary Of Loan Portfolio Segment Disaggregated By The Company's Impairment Method) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Financing Receivable, Impaired [Line Items]
Recorded investment in loans collectively evaluated for impairment	$ 6,215,503	$ 5,940,279
Recorded investment in loans individually evaluated for impairment	26,894	27,411
Financing receivable, total recorded investment	6,242,397	5,967,690
ACL for loans collectively evaluated for impairment	9,227	8,822
One-To Four-Family Loans - Originated [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment in loans collectively evaluated for impairment	5,431,203	5,107,899
Recorded investment in loans individually evaluated for impairment	13,871	12,950
Financing receivable, total recorded investment	5,445,074	5,120,849
ACL for loans collectively evaluated for impairment	6,263	5,771
One-To Four-Family Loans - Purchased [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment in loans collectively evaluated for impairment	552,951	634,705
Recorded investment in loans individually evaluated for impairment	12,405	13,882
Financing receivable, total recorded investment	565,356	648,587
ACL for loans collectively evaluated for impairment	2,323	2,486
One-To Four-Family Loans [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment in loans collectively evaluated for impairment	5,984,154	5,742,604
Recorded investment in loans individually evaluated for impairment	26,276	26,832
Financing receivable, total recorded investment	6,010,430	5,769,436
ACL for loans collectively evaluated for impairment	8,586	8,257
Multi-Family And Commercial [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment in loans collectively evaluated for impairment	96,946	57,603
Recorded investment in loans individually evaluated for impairment	0	0
Financing receivable, total recorded investment	96,946	57,603
ACL for loans collectively evaluated for impairment	400	185
Consumer [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment in loans collectively evaluated for impairment	134,403	140,072
Recorded investment in loans individually evaluated for impairment	618	579
Financing receivable, total recorded investment	135,021	140,651
ACL for loans collectively evaluated for impairment	$ 241	$ 380