v3.25.1
Loans Receivable and Allowance for Credit Losses (Modifications, Subsequent Default) (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Mar. 31, 2025
Mar. 31, 2024
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default $ 1,122   $ 1,363  
Payment Deferral [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 172   172  
Extended Maturity [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 193   193  
Extended Maturity and Payment Deferral [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 757 $ 93 998 $ 93
One- to Four-Family Segment [Member] | Originated [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 428   428  
One- to Four-Family Segment [Member] | Originated [Member] | Payment Deferral [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 84   84  
One- to Four-Family Segment [Member] | Originated [Member] | Extended Maturity [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 193   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 151 93 151 93
One- to Four-Family Segment [Member] | Correspondent Purchased [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 187   428  
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  
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  
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 187 0 428 0
One- to Four-Family Segment [Member] | Bulk Purchased [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 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  
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  
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 192   192  
Commercial Segment [Member] | Commercial Real Estate [Member] | Payment Deferral [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 0   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  
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 192 0 192 0
Commercial Segment [Member] | Commercial and Industrial [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 227   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  
Commercial Segment [Member] | Commercial and Industrial [Member] | Extended Maturity [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 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 227 0 227 0
Consumer Segment [Member] | Home Equity [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 88   88  
Consumer Segment [Member] | Home Equity [Member] | Payment Deferral [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 88   88  
Consumer Segment [Member] | Home Equity [Member] | Extended Maturity [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 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  
Consumer Segment [Member] | Other [Member] | Payment Deferral [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 0   0  
Consumer Segment [Member] | Other [Member] | Extended Maturity [Member]        
Financing Receivable, Modified, Subsequent Default [Line Items]        
Amortized Cost, Modified, Subsequent Default 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