Loans Receivable And Allowance For Credit Losses (Loans, Nonaccrual) (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Sep. 30, 2025
Financing Receivable, Past Due [Line Items]
Nonaccrual loans	$ 50,855	$ 47,796
Nonaccrual loans with no ACL	30,368	45,254
One- to Four-Family Segment [Member] \| Originated [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual loans	3,970	2,751
Nonaccrual loans with no ACL	1,885	1,833
One- to Four-Family Segment [Member] \| Correspondent Purchased [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual loans	3,449	1,409
Nonaccrual loans with no ACL	868	0
One- to Four-Family Segment [Member] \| Bulk Purchased [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual loans	285	135
Nonaccrual loans with no ACL	200	0
Commercial Segment [Member] \| Commercial Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual loans	42,327	43,087
Nonaccrual loans with no ACL	26,737	43,087
Commercial Segment [Member] \| Commercial and Industrial [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual loans	648	320
Nonaccrual loans with no ACL	648	320
Consumer Segment [Member] \| Home Equity [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual loans	138	46
Nonaccrual loans with no ACL	30	0
Consumer Segment [Member] \| Other [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual loans	38	48
Nonaccrual loans with no ACL	$ 0	$ 14