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Subsequent Events - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands | 3 Months Ended | 6 Months Ended | 12 Months Ended
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Dec. 31, 2024 | Sep. 30, 2024 | Jun. 30, 2024 | Mar. 31, 2024 | Dec. 31, 2023 | Sep. 30, 2023 | Jun. 30, 2023 | Mar. 31, 2023 | Dec. 31, 2022 | Sep. 30, 2022 | Jun. 30, 2022 | Mar. 31, 2022 | Dec. 31, 2024 | Dec. 31, 2025 | Dec. 31, 2024
Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common Stock, Dividends, Per Share, Declared | $ 0.50 | $ 0 | $ 0 | $ 0 | $ 0 | $ 0 | $ 0 | $ 0 | $ 0 | $ 0 | $ 0 | $ 0.06 |  |  |
Dividend paid to Parent Company | $ 14,300 |  |  |  |  |  |  |  | $ 26,000 |  |  |  | $ 14,300 |  | $ 14,300
Catastrophe Excess of Loss |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
First Event Retention Level | 20,500 |  |  |  |  |  |  |  |  |  |  |  | 20,500 |  | 20,500
Subsequent Event Retention Level | 13,000 |  |  |  |  |  |  |  |  |  |  |  | 13,000 |  | 13,000
American Coastal Insurance Company | All Other Perilds Catastrophe Excess of Loss |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Reinsurance, Excess Retention, Amount Reinsured, Per Policy |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 172,000
American Coastal Insurance Company | Catastrophe Excess of Loss |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Reinsurance, Excess Retention, Amount Reinsured, Per Policy |  |  |  |  |  |  |  |  |  |  |  |  | 1,610,000 |  |
Event Retention Level | 10,000 |  |  |  |  |  |  |  |  |  |  |  | 10,000 |  | 10,000
Reinsurance Retention Policy, Excess Retention, Amount Reinsured |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1,260,000
American Coastal Insurance Company | All Other Perils Catastrophe Excess of Loss |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Reinsurance, Amount Retained, Per Policy |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 14,000
Change In Reinsurance Retention Amount Retained, Per Policy | 4,000 |  |  |  |  |  |  |  |  |  |  |  | 4,000 |  | 4,000
Interboro Insurance | Catastrophe Excess of Loss |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Reinsurance, Excess Retention, Amount Reinsured, Per Policy |  |  |  |  |  |  |  |  |  |  |  |  | 82,500 |  |
Event Retention Level | $ 2,500 |  |  |  |  |  |  |  |  |  |  |  | $ 2,500 |  | $ 2,500
Subsequent Event | Catastrophe Excess of Loss |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
First Event Coverage |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 88,200 |
Second Event Coverage |  |  |  |  |  |  |  |  |  |  |  |  |  | 88,200 |
Subsequent Event | American Coastal Insurance Company | All Other Perilds Catastrophe Excess of Loss |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Reinsurance, Excess Retention, Amount Reinsured, Per Policy |  |  |  |  |  |  |  |  |  |  |  |  |  | 176,400 |
Change in Reinsurance, Excess Retention, Amount Reinsured, Per Policy |  |  |  |  |  |  |  |  |  |  |  |  |  | 4,400 |
Payments for Reinsurance |  |  |  |  |  |  |  |  |  |  |  |  |  | 11,900 |
Reinsurance Retention Policy, Excess Retention, Amount Reinsured |  |  |  |  |  |  |  |  |  |  |  |  |  | 90,000 |
Subsequent Event | American Coastal Insurance Company | Catastrophe Aggregate Excess of Loss |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Reinsurance, Excess Retention, Amount Reinsured, Per Policy |  |  |  |  |  |  |  |  |  |  |  |  |  | 40,000 |
Payments for Reinsurance |  |  |  |  |  |  |  |  |  |  |  |  |  | 6,600 |
Reinsurance, Amount Retained, Per Policy |  |  |  |  |  |  |  |  |  |  |  |  |  | 40,000 |
Subsequent Event | American Coastal Insurance Company | All Other Perils Catastrophe Excess of Loss |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Reinsurance, Amount Retained, Per Policy |  |  |  |  |  |  |  |  |  |  |  |  |  | 10,000 |
Subsequent Event | Interboro Insurance | Catastrophe Aggregate Excess of Loss |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Reinsurance Retention Policy, Excess Retention, Amount Reinsured |  |  |  |  |  |  |  |  |  |  |  |  |  | 20,000 |
Subsequent Event | Interboro Insurance | Catastrophe Excess of Loss |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Event Retention Level |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 9,800 |

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