Loans Receivable And Allowance For Credit Losses (Recorded Investment in Loans, Nonaccrual) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Sep. 30, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, nonaccrual loans	$ 21,969	$ 29,143
One- to Four-Family Segment [Member] | Originated [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, nonaccrual loans	13,721	17,086
One- to Four-Family Segment [Member] | Correspondent Purchased [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, nonaccrual loans	1,608	3,788
One- to Four-Family Segment [Member] | Bulk Purchased [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, nonaccrual loans	5,896	7,411
Commercial Real Estate Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, nonaccrual loans	0	0
Consumer Segment [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, nonaccrual loans	734	848
Consumer Segment [Member] | Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, nonaccrual loans	$ 10	$ 10