v3.26.3
Reserves for Unpaid Losses and Loss Adjustment Expenses (Details) - USD ($)
$ in Thousands
 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Dec. 31, 2025
Dec. 31, 2024
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]        
Gross reserves for unpaid losses and loss adjustment expenses, beginning of year $ 2,890,870 $ 2,285,668    
Reinsurance recoverable on unpaid losses 413,824 380,330 $ 381,356 $ 323,060
Net reserves for unpaid losses and loss adjustment expenses, beginning of year 2,509,514 1,962,608    
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]        
Current year 755,883 723,350    
Prior years (57,763) (45,853)    
Total net losses and loss adjustment expenses incurred 698,120 677,497    
Payments:        
Current year 48,193 43,393    
Prior years 248,989 211,855    
Total payments 297,182 255,248    
Net reserves for unpaid losses and loss adjustment expenses, end of period 2,910,452 2,384,857    
Reinsurance recoverable on unpaid losses 413,824 380,330 $ 381,356 $ 323,060
Gross reserves for unpaid losses and loss adjustment expenses, end of period $ 3,324,276 $ 2,765,187