v3.25.2
Fair Value (Estimated Fair Value Of Financial Instruments) (Details) - USD ($)
$ in Thousands
Jun. 30, 2025
Sep. 30, 2024
Carrying Amount    
Assets:    
Investment securities, available for sale $ 525,212 $ 526,251
Mortgage loans held for sale 30,977 17,775
Federal Home Loan Bank stock 232,538 228,494
Cash collateral received from or held by counterparty 5,977 7,844
Derivative 597 395
Liabilities:    
Borrowed funds 4,882,993 4,792,847
Carrying Amount | Checking And Passbook Accounts    
Liabilities:    
Deposits 2,055,056 2,150,770
Carrying Amount | Certificates of Deposit    
Liabilities:    
Deposits 8,286,443 8,044,309
Carrying Amount | Borrowers' Advances for insurance and Taxes    
Liabilities:    
Other Liabilities 117,899 113,637
Carrying Amount | Principal, Interest, And Escrow Owed On Loans Serviced    
Liabilities:    
Other Liabilities 30,237 28,753
Carrying Amount | Forward Commitments For Sale Of Mortgage Loans    
Liabilities:    
Derivative Liability 160 72
Carrying Amount | Cash and Due From Banks    
Assets:    
Cash and Cash Equivalents 28,788 26,287
Carrying Amount | Interest Earning Cash Equivalents    
Assets:    
Cash and Cash Equivalents 423,793 437,431
Carrying Amount | Total real estate loans    
Assets:    
Loans, net 15,588,252 15,316,354
Carrying Amount | Other Loans    
Assets:    
Loans, net 7,745 5,705
Carrying Amount | Accrued Interest Receivable    
Assets:    
Accrued interest receivable 60,434 59,398
Investment securities, available for sale 525,212 526,251
Mortgage loans held for sale 31,010 17,986
Federal Home Loan Bank stock 232,538 228,494
Cash collateral received from or held by counterparty 5,977 7,844
Derivative 597 395
Liabilities:    
Borrowed funds 4,903,129 4,819,873
Checking And Passbook Accounts    
Liabilities:    
Deposits 2,055,056 2,150,770
Certificates of Deposit    
Liabilities:    
Deposits 8,289,923 7,989,992
Borrowers' Advances for insurance and Taxes    
Liabilities:    
Other Liabilities 117,899 113,637
Principal, Interest, And Escrow Owed On Loans Serviced    
Liabilities:    
Other Liabilities 30,237 28,753
Forward Commitments For Sale Of Mortgage Loans    
Liabilities:    
Derivative Liability 160 72
Cash and Due From Banks    
Assets:    
Cash and Cash Equivalents 28,788 26,287
Interest Earning Cash Equivalents    
Assets:    
Cash and Cash Equivalents 423,793 437,431
Total real estate loans    
Assets:    
Loans, net 14,350,575 13,922,944
Other Loans    
Assets:    
Loans, net 7,745 5,705
Accrued Interest Receivable    
Assets:    
Accrued interest receivable 60,434 59,398
Fair Value, Inputs, Level 1    
Assets:    
Investment securities, available for sale 0 0
Mortgage loans held for sale 0 0
Cash collateral received from or held by counterparty 5,977 7,844
Derivative 0 0
Liabilities:    
Borrowed funds 0 0
Fair Value, Inputs, Level 1 | Checking And Passbook Accounts    
Liabilities:    
Deposits 0 0
Fair Value, Inputs, Level 1 | Certificates of Deposit    
Liabilities:    
Deposits 0 0
Fair Value, Inputs, Level 1 | Borrowers' Advances for insurance and Taxes    
Liabilities:    
Other Liabilities 0 0
Fair Value, Inputs, Level 1 | Principal, Interest, And Escrow Owed On Loans Serviced    
Liabilities:    
Other Liabilities 0 0
Fair Value, Inputs, Level 1 | Forward Commitments For Sale Of Mortgage Loans    
Liabilities:    
Derivative Liability 0 0
Fair Value, Inputs, Level 1 | Cash and Due From Banks    
Assets:    
Cash and Cash Equivalents 28,788 26,287
Fair Value, Inputs, Level 1 | Interest Earning Cash Equivalents    
Assets:    
Cash and Cash Equivalents 423,793 437,431
Fair Value, Inputs, Level 1 | Total real estate loans    
Assets:    
Loans, net 0 0
Fair Value, Inputs, Level 1 | Other Loans    
Assets:    
Loans, net 0 0
Fair Value, Inputs, Level 1 | Accrued Interest Receivable    
Assets:    
Accrued interest receivable 0 0
Fair Value, Inputs, Level 2    
Assets:    
Investment securities, available for sale 525,212 526,251
Mortgage loans held for sale 31,010 17,986
Federal Home Loan Bank stock 0 0
Cash collateral received from or held by counterparty 0 0
Derivative 0 0
Liabilities:    
Borrowed funds 4,903,129 4,819,873
Fair Value, Inputs, Level 2 | Checking And Passbook Accounts    
Liabilities:    
Deposits 2,055,056 2,150,770
Fair Value, Inputs, Level 2 | Certificates of Deposit    
Liabilities:    
Deposits 8,289,923 7,989,992
Fair Value, Inputs, Level 2 | Borrowers' Advances for insurance and Taxes    
Liabilities:    
Other Liabilities 117,899 113,637
Fair Value, Inputs, Level 2 | Principal, Interest, And Escrow Owed On Loans Serviced    
Liabilities:    
Other Liabilities 30,237 28,753
Fair Value, Inputs, Level 2 | Forward Commitments For Sale Of Mortgage Loans    
Liabilities:    
Derivative Liability 160 72
Fair Value, Inputs, Level 2 | Cash and Due From Banks    
Assets:    
Cash and Cash Equivalents 0 0
Fair Value, Inputs, Level 2 | Interest Earning Cash Equivalents    
Assets:    
Cash and Cash Equivalents 0 0
Fair Value, Inputs, Level 2 | Total real estate loans    
Assets:    
Loans, net 0 0
Fair Value, Inputs, Level 2 | Other Loans    
Assets:    
Loans, net 0 0
Fair Value, Inputs, Level 2 | Accrued Interest Receivable    
Assets:    
Accrued interest receivable 60,434 59,398
Fair Value, Inputs, Level 3    
Assets:    
Investment securities, available for sale 0 0
Mortgage loans held for sale 0 0
Federal Home Loan Bank stock 0 0
Cash collateral received from or held by counterparty 0 0
Derivative 597 395
Liabilities:    
Borrowed funds 0 0
Fair Value, Inputs, Level 3 | Checking And Passbook Accounts    
Liabilities:    
Deposits 0 0
Fair Value, Inputs, Level 3 | Certificates of Deposit    
Liabilities:    
Deposits 0 0
Fair Value, Inputs, Level 3 | Borrowers' Advances for insurance and Taxes    
Liabilities:    
Other Liabilities 0 0
Fair Value, Inputs, Level 3 | Principal, Interest, And Escrow Owed On Loans Serviced    
Liabilities:    
Other Liabilities 0 0
Fair Value, Inputs, Level 3 | Forward Commitments For Sale Of Mortgage Loans    
Liabilities:    
Derivative Liability 0 0
Fair Value, Inputs, Level 3 | Cash and Due From Banks    
Assets:    
Cash and Cash Equivalents 0 0
Fair Value, Inputs, Level 3 | Interest Earning Cash Equivalents    
Assets:    
Cash and Cash Equivalents 0 0
Fair Value, Inputs, Level 3 | Total real estate loans    
Assets:    
Loans, net 14,350,575 13,922,944
Fair Value, Inputs, Level 3 | Other Loans    
Assets:    
Loans, net 7,745 5,705
Fair Value, Inputs, Level 3 | Accrued Interest Receivable    
Assets:    
Accrued interest receivable $ 0 $ 0