v3.26.1
Loss and Loss Adjustment Expense Reserves - Reconciliation of Losses and Loss Adjustment Expenses (Details) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]    
Reserve for losses and LAE gross of reinsurance recoverables on unpaid losses and LAE as of beginning of the period $ 420.4 $ 350.0
Reinsurance recoverables on unpaid losses and LAE (289.0) (229.9)
Reserve for losses and LAE, net of reinsurance recoverables as of beginning of the period 131.4 120.1
Add: Incurred losses and LAE, net of reinsurance, related to:    
Current year 50.0 95.4
Prior years (2.5) (3.0)
Total incurred 47.5 92.4
Deduct: Loss and LAE payments, net of reinsurance, related to:    
Current year 11.7 50.3
Prior year 24.1 26.8
Total paid 35.8 77.1
Reserve for losses and LAE, net of reinsurance recoverables at end of period 143.1 135.4
Add: Reinsurance recoverables on unpaid losses and LAE at end of period 339.5 265.4
Reserve for losses and LAE gross of reinsurance recoverables on unpaid losses and LAE as of end of the period 482.6 400.8
Attritional reserves release 1.5 2.9
Catastrophe reserves release $ 1.0 $ 0.1