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	Dec. 31, 2013	Sep. 30, 2013
Financing Receivable, Impaired [Line Items]
Recorded investment in loans collectively evaluated for impairment	$ 6,004,239	$ 5,940,279
Recorded investment in loans individually evaluated for impairment	29,269	27,411
Financing receivable, Total Recorded Investment	6,033,508	5,967,690
ACL for loans collectively evaluated for impairment	8,919	8,822
One-To Four-Family Loans - Originated [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment in loans collectively evaluated for impairment	5,206,930	5,107,899
Recorded investment in loans individually evaluated for impairment	14,730	12,950
Financing receivable, Total Recorded Investment	5,221,660	5,120,849
ACL for loans collectively evaluated for impairment	5,839	5,771
One-To Four-Family Loans - Purchased [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment in loans collectively evaluated for impairment	610,272	634,705
Recorded investment in loans individually evaluated for impairment	13,857	13,882
Financing receivable, Total Recorded Investment	624,129	648,587
ACL for loans collectively evaluated for impairment	2,513	2,486
One-To Four-Family Loans [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment in loans collectively evaluated for impairment	5,817,202	5,742,604
Recorded investment in loans individually evaluated for impairment	28,587	26,832
Financing receivable, Total Recorded Investment	5,845,789	5,769,436
ACL for loans collectively evaluated for impairment	8,352	8,257
Multi-Family And Commercial [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment in loans collectively evaluated for impairment	47,229	57,603
Financing receivable, Total Recorded Investment	47,229	57,603
ACL for loans collectively evaluated for impairment	182	185
Consumer [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment in loans collectively evaluated for impairment	139,808	140,072
Recorded investment in loans individually evaluated for impairment	682	579
Financing receivable, Total Recorded Investment	140,490	140,651
ACL for loans collectively evaluated for impairment	$ 385	$ 380