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Contracts Accounted for as Insurance - Additional Information (Details) | 9 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2025 | Dec. 31, 2024
Guarantor Obligations [Line Items] |  |
Weighted average risk-free rates for U.S. dollar denominated financial guaranty insurance obligations | 4.03% | 4.38%
Minimum |  |
Guarantor Obligations [Line Items] |  |
Weighted average risk-free rates for U.S. dollar denominated financial guaranty insurance obligations | 1.92% | 1.98%
Maximum |  |
Guarantor Obligations [Line Items] |  |
Weighted average risk-free rates for U.S. dollar denominated financial guaranty insurance obligations | 5.70% | 5.22%
Foreign Currency Concentration Risk | Premiums Receivable | Premiums Receivable |  |
Guarantor Obligations [Line Items] |  |
Percentage of installment premiums denominated in currencies other than the U.S. dollar | 68.00% | 69.00%

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