Loans Receivable And Allowance For Credit Losses (Summary Of Loans Receivable) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Sep. 30, 2016
Loans Receivable [Line Items]
Loans receivable, gross	$ 7,228,425	$ 6,949,522
Total real estate loans	7,104,409	6,821,913
ACL	8,486	8,540
Discounts/unearned loan fees	25,221	24,933
Premiums/deferred costs	(45,876)	(41,975)
Loans receivable, net	7,240,594	6,958,024
One- to Four-Family Segment [Member]
Loans Receivable [Line Items]
Loans receivable, gross	6,848,845	6,667,770
One- to Four-Family Segment [Member] \| Originated [Member]
Loans Receivable [Line Items]
Loans receivable, gross	4,005,081	4,005,615
One- to Four-Family Segment [Member] \| Correspondent Purchased [Member]
Loans Receivable [Line Items]
Loans receivable, gross	2,442,557	2,206,072
One- to Four-Family Segment [Member] \| Bulk Purchased [Member]
Loans Receivable [Line Items]
Loans receivable, gross	367,353	416,653
One- to Four-Family Segment [Member] \| Construction [Member]
Loans Receivable [Line Items]
Loans receivable, gross	33,854	39,430
Commercial Real Estate Segment [Member]
Loans Receivable [Line Items]
Loans receivable, gross	255,564	154,143
Commercial Real Estate Segment [Member] \| Construction [Member]
Loans Receivable [Line Items]
Loans receivable, gross	107,079	43,375
Commercial Real Estate Segment [Member] \| Permanent [Member]
Loans Receivable [Line Items]
Loans receivable, gross	148,485	110,768
Consumer Segment [Member]
Loans Receivable [Line Items]
Loans receivable, gross	124,016	127,609
Consumer Segment [Member] \| Home Equity [Member]
Loans Receivable [Line Items]
Loans receivable, gross	119,822	123,345
Consumer Segment [Member] \| Other [Member]
Loans Receivable [Line Items]
Loans receivable, gross	$ 4,194	$ 4,264

Loans And Leases Receivable Premiums Deferred Costs

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Total (gross) amount of real estate loans, including unamortized fees, discounts, expenses, and premiums, and undisbursed loan funds.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount, before allowance and fees, of loans and leases receivable. Excludes loans and leases covered under loss sharing agreements.

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Amount of deferred interest and fee income, unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of acquired loans. Excludes amounts for loans and leases covered under loss sharing agreements.

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