v3.26.1
Fair Value Measurements: Balances of assets measured at estimated fair value on a non-recurring basis, and total losses resulting from estimated fair value adjustments (Details) - Nonrecurring - USD ($)
$ in Thousands
Jun. 30, 2026
Sep. 30, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, estimated fair value, nonrecurring $ 4,718 $ 398
Commercial real estate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, estimated fair value, nonrecurring 3,830  
Commercial business    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, estimated fair value, nonrecurring 667 177
Total loans    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, estimated fair value, nonrecurring 4,497 177
OREO and other repossessed assets    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, estimated fair value, nonrecurring 221 221
Fair Value, Inputs, Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, estimated fair value, nonrecurring 0 0
Fair Value, Inputs, Level 1 | Commercial real estate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, estimated fair value, nonrecurring 0  
Fair Value, Inputs, Level 1 | Commercial business    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, estimated fair value, nonrecurring 0 0
Fair Value, Inputs, Level 1 | Total loans    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, estimated fair value, nonrecurring 0 0
Fair Value, Inputs, Level 1 | OREO and other repossessed assets    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, estimated fair value, nonrecurring 0 0
Fair Value, Inputs, Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, estimated fair value, nonrecurring 0 0
Fair Value, Inputs, Level 2 | Commercial real estate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, estimated fair value, nonrecurring 0  
Fair Value, Inputs, Level 2 | Commercial business    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, estimated fair value, nonrecurring 0 0
Fair Value, Inputs, Level 2 | Total loans    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, estimated fair value, nonrecurring 0 0
Fair Value, Inputs, Level 2 | OREO and other repossessed assets    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, estimated fair value, nonrecurring 0 0
Fair Value, Inputs, Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, estimated fair value, nonrecurring 4,718 398
Fair Value, Inputs, Level 3 | Commercial real estate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, estimated fair value, nonrecurring 3,830  
Fair Value, Inputs, Level 3 | Commercial business    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, estimated fair value, nonrecurring 667 177
Fair Value, Inputs, Level 3 | Total loans    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, estimated fair value, nonrecurring 4,497 177
Fair Value, Inputs, Level 3 | OREO and other repossessed assets    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, estimated fair value, nonrecurring $ 221 $ 221