v3.26.1
Reserve for Losses and Loss Adjustment Expenses - Reserve for Losses and Loss Adjustment Expenses, Net of Reinsurance (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Liability for Unpaid Claims and Claims Adjustment Expense, Period Increase (Decrease) [Abstract]          
Reserve for losses and loss adjustment expenses net of reinsurance recoverables at beginning of period $ 1,071,619 $ 1,095,761 $ 1,071,699 $ 1,086,278 $ 1,086,278
Add: Incurred losses and loss adjustment expenses net of reinsurance:          
Current year 91,609 100,875 185,745 202,459  
Prior years - retroactive reinsurance impact 6,927 9,239 21,116 7,311  
Prior years - excluding retroactive reinsurance 569 3,027 404 2,896  
Total incurred losses and loss adjustment expenses 99,105 113,141 207,265 212,666  
Deduct: Loss and loss adjustment expense payments net of reinsurance:          
Current year 2,438 4,005 3,338 5,736  
Prior years 105,063 106,477 198,214 196,716  
Total loss and loss adjustment expense payments 107,501 110,482 201,552 202,452  
Reserve for losses and loss adjustment expenses net of reinsurance recoverables at end of period 1,056,296 1,089,181 1,056,296 1,089,181 1,071,699
Add: Reinsurance recoverables on unpaid losses and loss adjustment expenses at end of period 2,033,749 1,987,317 2,033,749 1,987,317  
Reserve for losses and loss adjustment expenses gross of reinsurance recoverables on unpaid losses and loss adjustment expenses at end of period 3,090,045 3,076,498 3,090,045 3,076,498 $ 3,099,418
Excess & Surplus Lines          
Add: Incurred losses and loss adjustment expenses net of reinsurance:          
Prior years - retroactive reinsurance impact 6,927 9,239 21,116 7,311  
Prior years - excluding retroactive reinsurance 275 2,300 175 2,300  
Deduct: Loss and loss adjustment expense payments net of reinsurance:          
Deduct: Change in deferred reinsurance gain - retroactive reinsurance $ 6,927 $ 9,239 $ 21,116 $ 7,311