Loans Receivable And Allowance For Credit Losses (Summary Of Loan Portfolio Segment Disaggregated By The Company's Impairment Method) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Sep. 30, 2015
Financing Receivable, Impaired [Line Items]
Recorded investment in loans collectively evaluated for impairment	$ 6,824,774	$ 6,611,662
Recorded investment in loans individually evaluated for impairment	23,661	22,808
Financing receivable, total recorded investment	6,848,435	6,634,470
ACL for loans collectively evaluated for impairment	9,312	9,443
One- to Four-Family Segment [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment in loans collectively evaluated for impairment	6,565,773	6,361,838
Recorded investment in loans individually evaluated for impairment	23,023	22,204
Financing receivable, total recorded investment	6,588,796	6,384,042
ACL for loans collectively evaluated for impairment	8,116	8,414
One- to Four-Family Segment [Member] \| Originated [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment in loans collectively evaluated for impairment	6,134,336	5,884,498
Recorded investment in loans individually evaluated for impairment	12,128	11,169
Financing receivable, total recorded investment	6,146,464	5,895,667
ACL for loans collectively evaluated for impairment	6,967	6,980
One- to Four-Family Segment [Member] \| Purchased [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment in loans collectively evaluated for impairment	431,437	477,340
Recorded investment in loans individually evaluated for impairment	10,895	11,035
Financing receivable, total recorded investment	442,332	488,375
ACL for loans collectively evaluated for impairment	1,149	1,434
Commercial Real Estate Segment [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment in loans collectively evaluated for impairment	131,398	120,405
Recorded investment in loans individually evaluated for impairment	0	0
Financing receivable, total recorded investment	131,398	120,405
ACL for loans collectively evaluated for impairment	933	742
Consumer Segment [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment in loans collectively evaluated for impairment	127,603	129,419
Recorded investment in loans individually evaluated for impairment	638	604
Financing receivable, total recorded investment	128,241	130,023
ACL for loans collectively evaluated for impairment	$ 263	$ 287

The balance of financing receivables that were individually evaluated for impairment.

No definition available.

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- Definition

The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953423-111524

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- Definition

The balance of financing receivables that were collectively evaluated for impairment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (h)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953423-111524

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+ References

No definition available.

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- Definition

Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=65884687&loc=d3e4428-111522

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5074-111524

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