v3.26.1
Loans Receivable and Allowance for Credit Losses (Modifications, Subsequent Default) (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default $ 1,327 $ 193 $ 1,778 $ 1,353
Payment Deferral [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 914 0 914 167
Extended Maturity [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 259 193 614 193
Extended Maturity and Payment Deferral [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 154 0 250 993
One- to Four-Family Segment [Member] | Originated [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 413 193 864 423
One- to Four-Family Segment [Member] | Originated [Member] | Payment Deferral [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 0 0 0 82
One- to Four-Family Segment [Member] | Originated [Member] | Extended Maturity [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 259 193 614 193
One- to Four-Family Segment [Member] | Originated [Member] | Extended Maturity and Payment Deferral [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 154 0 250 148
One- to Four-Family Segment [Member] | Correspondent Purchased [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 0 0 0 426
One- to Four-Family Segment [Member] | Correspondent Purchased [Member] | Payment Deferral [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 0 0 0 0
One- to Four-Family Segment [Member] | Correspondent Purchased [Member] | Extended Maturity [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 0 0 0 0
One- to Four-Family Segment [Member] | Correspondent Purchased [Member] | Extended Maturity and Payment Deferral [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 0 0 0 426
One- to Four-Family Segment [Member] | Bulk Purchased [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 0 0 0 0
One- to Four-Family Segment [Member] | Bulk Purchased [Member] | Payment Deferral [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 0 0 0 0
One- to Four-Family Segment [Member] | Bulk Purchased [Member] | Extended Maturity [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 0 0 0 0
One- to Four-Family Segment [Member] | Bulk Purchased [Member] | Extended Maturity and Payment Deferral [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 0 0 0 0
Commercial Segment [Member] | Commercial Real Estate [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 914 0 914 192
Commercial Segment [Member] | Commercial Real Estate [Member] | Payment Deferral [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 914 0 914 0
Commercial Segment [Member] | Commercial Real Estate [Member] | Extended Maturity [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 0 0 0 0
Commercial Segment [Member] | Commercial Real Estate [Member] | Extended Maturity and Payment Deferral [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 0 0 0 192
Commercial Segment [Member] | Commercial and Industrial [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 0 0 0 227
Commercial Segment [Member] | Commercial and Industrial [Member] | Payment Deferral [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 0 0 0 0
Commercial Segment [Member] | Commercial and Industrial [Member] | Extended Maturity [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 0 0 0 0
Commercial Segment [Member] | Commercial and Industrial [Member] | Extended Maturity and Payment Deferral [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 0 0 0 227
Consumer Segment [Member] | Home Equity [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 0 0 0 85
Consumer Segment [Member] | Home Equity [Member] | Payment Deferral [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 0 0 0 85
Consumer Segment [Member] | Home Equity [Member] | Extended Maturity [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 0 0 0 0
Consumer Segment [Member] | Home Equity [Member] | Extended Maturity and Payment Deferral [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 0 0 0 0
Consumer Segment [Member] | Other [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 0 0 0 0
Consumer Segment [Member] | Other [Member] | Payment Deferral [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 0 0 0 0
Consumer Segment [Member] | Other [Member] | Extended Maturity [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 0 0 0 0
Consumer Segment [Member] | Other [Member] | Extended Maturity and Payment Deferral [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default $ 0 $ 0 $ 0 $ 0