Loans Receivable And Allowance For Credit Losses (Recorded Investment in Loans, Nonaccrual) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Sep. 30, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, nonaccrual loans	$ 28,824	$ 29,143
One- to Four-Family Segment [Member] | Originated [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, nonaccrual loans	17,985	17,086
One- to Four-Family Segment [Member] | Correspondent Purchased [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, nonaccrual loans	1,794	3,788
One- to Four-Family Segment [Member] | Bulk Purchased [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, nonaccrual loans	8,200	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	827	848
Consumer Segment [Member] | Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivable, nonaccrual loans	$ 18	$ 10