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v3.25.3

Reinsurance (Schedule of Trust Assets and Reinsurance Liabilities) (Details) - USD ($) $ in Millions | Sep. 30, 2025 | Dec. 31, 2024 | Sep. 30, 2024 | Dec. 31, 2023
--- | --- | --- | --- | ---
Reinsurance [Line Items] |  |  |  |  |
Restricted cash and cash equivalents |  | $ 482.9 | $ 501.3 | $ 556.6 | $ 457.7
Debt Securities, Available-for-sale, Restricted |  | 108.9 | 106.4 |  |
Trust Assets [Member] |  |  |  |  |
Reinsurance [Line Items] |  |  |  |  |
Restricted cash and cash equivalents |  | 0.3 | 0.3 |  |
Debt Securities, Available-for-sale, Restricted |  | 108.9 | 106.4 |  |
Unearned Premium [Member] |  |  |  |  |
Reinsurance [Line Items] |  |  |  |  |
Accounts payable and accrued liabilities |  | 76.6 | 75.9 |  |
Claims Reserve [Member] |  |  |  |  |
Reinsurance [Line Items] |  |  |  |  |
Accounts payable and accrued liabilities | [1] | $ 6.2 | $ 6.0 |  |
[1] | The claims reserve represents our liability for incurred-but-not-reported claims and is estimated based on historical claims experience.

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