v3.26.1
Reinsurance - Additional Information (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Reinsurance Retention Policy        
Ceded Premiums Earned $ 69,032 $ 87,017 $ 144,555 $ 180,846
Catastrophe Excess of Loss        
Reinsurance Retention Policy        
Retension loss events 100,000   100,000  
Third event retention level 2,000   2,000  
First event retention level 49,000   49,000  
Second event retention level 25,000   25,000  
Catastrophe Excess of Loss | Shoreline Re        
Reinsurance Retention Policy        
First event retention level 22,500   22,500  
Subsequent event retention level 11,700   $ 11,700  
Quota Share Agreement | Shoreline Re        
Reinsurance Retention Policy        
Cession Rate     45.00%  
American Coastal Insurance Company | Catastrophe Excess of Loss        
Reinsurance Retention Policy        
Insured long term debt project demand decrease     $ 78,000,000  
Program provides sufficient coverage period     1-in-100-year  
Percentage of singe occurrence exceeding protection purchased     0.40%  
Percentage of loss adjustment expense     10.00%  
Program provides sufficient coverage return period     1-in-286-year  
Reinsurance, excess retention, amount reinsured, per policy     $ 1,918,000  
Event retention level 26,500   26,500  
Second event retention level 13,300   13,300  
Reinsurance, excess retention, amount reinsured, per event     $ 1,680,000  
American Coastal Insurance Company | Catastrophe Excess of Loss | Maximum        
Reinsurance Retention Policy        
Program provides sufficient coverage probability rate     0.10%  
American Coastal Insurance Company | All Other Perilds Catastrophe Excess of Loss        
Reinsurance Retention Policy        
Percentage of singe occurrence exceeding protection purchased     0.50%  
Program provides sufficient coverage return period     1-in-227-year  
Reinsurance, excess retention, amount reinsured, per policy     $ 170,400  
Reinsurance, excess retention level per event 95,600   95,600  
American Coastal Insurance Company | Catastrophe Aggregate Excess of Loss        
Reinsurance Retention Policy        
Reinsurance, excess retention, amount reinsured, per policy     40,000  
Event occurrence limit $ 20,000   20,000  
Reinsurance, aggregate retention     $ 40,000