v3.25.1
Loans Receivable and Allowance For Credit Losses (Modifications on Financing Receivables) (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 [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount $ 11,993   $ 13,205  
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage 0.15% 0.06% 0.17% 0.12%
Payment Deferral [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount $ 8,425   $ 8,562  
Extended Maturity [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount 2,730   3,640  
Extended Maturity and Payment Deferral [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount 838 $ 4,968 1,003 $ 9,822
One- to Four-Family Segment [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount $ 2,931   $ 4,124  
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage 0.05% 0.07% 0.07% 0.14%
One- to Four-Family Segment [Member] | Payment Deferral [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount $ 236   $ 353  
One- to Four-Family Segment [Member] | Extended Maturity [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount 1,857   2,768  
One- to Four-Family Segment [Member] | Extended Maturity and Payment Deferral [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount 838 $ 4,275 1,003 $ 9,129
One- to Four-Family Segment [Member] | Originated [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount $ 2,231   $ 3,424  
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage 0.06% 0.09% 0.09% 0.19%
One- to Four-Family Segment [Member] | Originated [Member] | Payment Deferral [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount $ 236   $ 353  
One- to Four-Family Segment [Member] | Originated [Member] | Extended Maturity [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount 1,344   2,255  
One- to Four-Family Segment [Member] | Originated [Member] | Extended Maturity and Payment Deferral [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount 651 $ 3,429 816 $ 7,385
One- to Four-Family Segment [Member] | Correspondent Purchased [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount $ 700   $ 700  
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage 0.03% 0.04% 0.03% 0.07%
One- to Four-Family Segment [Member] | Correspondent Purchased [Member] | Payment Deferral [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount $ 0   $ 0  
One- to Four-Family Segment [Member] | Correspondent Purchased [Member] | Extended Maturity [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount 513   513  
One- to Four-Family Segment [Member] | Correspondent Purchased [Member] | Extended Maturity and Payment Deferral [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount 187 $ 845 187 $ 1,744
One- to Four-Family Segment [Member] | Bulk Purchased [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount $ 0   $ 0  
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage 0.00% 0.00% 0.00% 0.00%
One- to Four-Family Segment [Member] | Bulk Purchased [Member] | Payment Deferral [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount $ 0   $ 0  
One- to Four-Family Segment [Member] | Bulk Purchased [Member] | Extended Maturity [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount 0   0  
One- to Four-Family Segment [Member] | Bulk Purchased [Member] | Extended Maturity and Payment Deferral [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount 0 $ 0 0 $ 0
Commercial Segment [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount $ 9,027   $ 9,027  
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage 0.54% 0.05% 0.54% 0.05%
Commercial Segment [Member] | Payment Deferral [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount $ 8,189   $ 8,189  
Commercial Segment [Member] | Extended Maturity [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount 838   838  
Commercial Segment [Member] | Extended Maturity and Payment Deferral [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount 0 $ 693 0 $ 693
Commercial Segment [Member] | Commercial Real Estate [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount $ 8,189   $ 8,189  
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage 0.54% 0.02% 0.54% 0.02%
Commercial Segment [Member] | Commercial Real Estate [Member] | Payment Deferral [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount $ 8,189   $ 8,189  
Commercial Segment [Member] | Commercial Real Estate [Member] | Extended Maturity [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount 0   0  
Commercial Segment [Member] | Commercial Real Estate [Member] | Extended Maturity and Payment Deferral [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount 0 $ 238 0 $ 238
Commercial Segment [Member] | Commercial and Industrial [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount $ 838   $ 838  
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage 0.62% 0.41% 0.62% 0.41%
Commercial Segment [Member] | Commercial and Industrial [Member] | Payment Deferral [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount $ 0   $ 0  
Commercial Segment [Member] | Commercial and Industrial [Member] | Extended Maturity [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount 838   838  
Commercial Segment [Member] | Commercial and Industrial [Member] | Extended Maturity and Payment Deferral [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount 0 $ 455 0 $ 455
Consumer Segment [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount $ 35   $ 54  
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage 0.03% 0.00% 0.05% 0.00%
Consumer Segment [Member] | Payment Deferral [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount $ 0   $ 20  
Consumer Segment [Member] | Extended Maturity [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount 35   34  
Consumer Segment [Member] | Extended Maturity and Payment Deferral [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount 0 $ 0 0 $ 0
Consumer Segment [Member] | Home Equity [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount $ 35   $ 54  
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage 0.03% 0.00% 0.05% 0.00%
Consumer Segment [Member] | Home Equity [Member] | Payment Deferral [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount $ 0   $ 20  
Consumer Segment [Member] | Home Equity [Member] | Extended Maturity [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount 35   34  
Consumer Segment [Member] | Home Equity [Member] | Extended Maturity and Payment Deferral [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount 0 $ 0 0 $ 0
Consumer Segment [Member] | Other [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount $ 0   $ 0  
Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage 0.00% 0.00% 0.00% 0.00%
Consumer Segment [Member] | Other [Member] | Payment Deferral [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount $ 0   $ 0  
Consumer Segment [Member] | Other [Member] | Extended Maturity [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount 0   0  
Consumer Segment [Member] | Other [Member] | Extended Maturity and Payment Deferral [Member]        
Financing Receivable, Modified [Line Items]        
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount $ 0 $ 0 $ 0 $ 0