Loans Receivable And Allowance For Credit Losses (Loans, Nonaccrual) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Sep. 30, 2021
Financing Receivable, Past Due [Line Items]
Financing receivable, nonaccrual loans	$ 11,220	$ 13,493
Financing Receivable, nonaccrual loans with no ACL	3,868	4,763
One- to Four-Family Segment [Member] | Originated [Member]
Financing Receivable, Past Due [Line Items]
Financing receivable, nonaccrual loans	4,385	4,965
Financing Receivable, nonaccrual loans with no ACL	1,835	2,237
One- to Four-Family Segment [Member] | Correspondent Purchased [Member]
Financing Receivable, Past Due [Line Items]
Financing receivable, nonaccrual loans	3,158	3,257
Financing Receivable, nonaccrual loans with no ACL	307	307
One- to Four-Family Segment [Member] | Bulk Purchased [Member]
Financing Receivable, Past Due [Line Items]
Financing receivable, nonaccrual loans	1,968	3,134
Financing Receivable, nonaccrual loans with no ACL	1,062	1,564
Commercial Segment [Member] | Commercial Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing receivable, nonaccrual loans	1,108	1,496
Financing Receivable, nonaccrual loans with no ACL	457	485
Commercial Segment [Member] | Commercial and Industrial [Member]
Financing Receivable, Past Due [Line Items]
Financing receivable, nonaccrual loans	124	134
Financing Receivable, nonaccrual loans with no ACL	124	86
Consumer Segment [Member] | Home Equity [Member]
Financing Receivable, Past Due [Line Items]
Financing receivable, nonaccrual loans	466	494
Financing Receivable, nonaccrual loans with no ACL	83	84
Consumer Segment [Member] | Other [Member]
Financing Receivable, Past Due [Line Items]
Financing receivable, nonaccrual loans	11	13
Financing Receivable, nonaccrual loans with no ACL	$ 0	$ 0