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Commitments and Contingencies (Narrative) (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
--- | --- | ---
Mar. 31, 2023 | Mar. 31, 2022 | Jun. 30, 2022
Commitments and Contingencies Disclosure [Abstract] |  |  |
Financial guarantees in connection with standby letters of credit | $ 0 | $ 0 |
Standby letters of credit expiring within one year | 131,700 |  |
Standby letters of credit expiring thereafter | 24,200 |  |
Residential mortgage loan repurchase reserve liability | 200 |  |
Loss Contingency Accrual | 3,900 |  |
Concentration Risk [Line Items] |  |  |
Prior Bankruptcy Recoveries by Plaintiffs | 110,000 |  |
GNMA Loans past due by 90 days, but not yet repurchased | 5,400 |  |
Minimum |  |  |
Concentration Risk [Line Items] |  |  |
Loss Contingency, Damages Sought, Value | 386,200 |  |
Maximum |  |  |
Concentration Risk [Line Items] |  |  |
Loss Contingency, Damages Sought, Value | $ 429,800 |  |
Product Concentration Risk | Revenue Benchmark | Real Estate Loans As Part Of Loan Portfolio |  |  |
Concentration Risk [Line Items] |  |  |
Concentration risk (as a percent) | 74.00% |  | 78.00%

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