Loans Receivable And Allowance For Credit Losses (Recorded Investment in Loans, Nonaccrual) (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Sep. 30, 2019
Financing Receivable, Past Due [Line Items]
Financing receivable, nonaccrual loans	$ 10,254	$ 7,541
One- to Four-Family Segment [Member] | Originated [Member]
Financing Receivable, Past Due [Line Items]
Financing receivable, nonaccrual loans	4,955	4,436
One- to Four-Family Segment [Member] | Correspondent Purchased [Member]
Financing Receivable, Past Due [Line Items]
Financing receivable, nonaccrual loans	2,971	1,023
One- to Four-Family Segment [Member] | Bulk Purchased [Member]
Financing Receivable, Past Due [Line Items]
Financing receivable, nonaccrual loans	1,305	1,551
Commercial Segment [Member] | Commercial Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing receivable, nonaccrual loans	546	0
Commercial Segment [Member] | Commercial and Industrial [Member]
Financing Receivable, Past Due [Line Items]
Financing receivable, nonaccrual loans	165	173
Consumer Segment [Member] | Home Equity [Member]
Financing Receivable, Past Due [Line Items]
Financing receivable, nonaccrual loans	282	337
Consumer Segment [Member] | Other [Member]
Financing Receivable, Past Due [Line Items]
Financing receivable, nonaccrual loans	$ 30	$ 21