Loans Receivable And Allowance For Credit Losses (Loans, Nonaccrual) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020
Financing Receivable, Past Due [Line Items]
Financing receivable, nonaccrual loans	$ 13,493	$ 12,541
Financing Receivable, nonaccrual loans with no ACL	4,763
One- to Four-Family Segment [Member] | Originated [Member]
Financing Receivable, Past Due [Line Items]
Financing receivable, nonaccrual loans	4,965	5,037
Financing Receivable, nonaccrual loans with no ACL	2,237
One- to Four-Family Segment [Member] | Correspondent Purchased [Member]
Financing Receivable, Past Due [Line Items]
Financing receivable, nonaccrual loans	3,257	2,433
Financing Receivable, nonaccrual loans with no ACL	307
One- to Four-Family Segment [Member] | Bulk Purchased [Member]
Financing Receivable, Past Due [Line Items]
Financing receivable, nonaccrual loans	3,134	2,938
Financing Receivable, nonaccrual loans with no ACL	1,564
Commercial Segment [Member] | Commercial Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing receivable, nonaccrual loans	1,496	1,663
Financing Receivable, nonaccrual loans with no ACL	485
Commercial Segment [Member] | Commercial and Industrial [Member]
Financing Receivable, Past Due [Line Items]
Financing receivable, nonaccrual loans	134	157
Financing Receivable, nonaccrual loans with no ACL	86
Consumer Segment [Member] | Home Equity [Member]
Financing Receivable, Past Due [Line Items]
Financing receivable, nonaccrual loans	494	305
Financing Receivable, nonaccrual loans with no ACL	84
Consumer Segment [Member] | Other [Member]
Financing Receivable, Past Due [Line Items]
Financing receivable, nonaccrual loans	13	$ 8
Financing Receivable, nonaccrual loans with no ACL	$ 0