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Reinsurance - Narrative (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2024 | Sep. 30, 2023 | Sep. 30, 2024 | Sep. 30, 2023
Effects of Reinsurance [Line Items] |  |  |  |
Percentage of NFIP | 100.00% |  | 100.00% |
Ceded loss and loss expense | $ 434,670 | $ 103,573 | $ 579,255 | $ 213,161
Effect in direct loss and loss expense incurred |  |  | 182,748 | (5,782)
Casualty lines |  |  |  |
Effects of Reinsurance [Line Items] |  |  |  |
Effect in direct loss and loss expense incurred |  |  | 211,000 | $ (16,500)
National Flood Insurance Program |  |  |  |
Effects of Reinsurance [Line Items] |  |  |  |
Increase of NFIP reserves | $ 232,800 |  |  |
Total rated reinsurers |  |  |  |
Effects of Reinsurance [Line Items] |  |  |  |
Change in reinsurance recoverable gross |  |  | 155,900 |
Federal and state pools |  |  |  |
Effects of Reinsurance [Line Items] |  |  |  |
Change in reinsurance recoverable gross |  |  | $ 244,600 |

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