v3.26.1
Investment Securities - Cost and Amortized Cost Maturity Schedule (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Fixed Maturities, Excluding Asset-Backed Securities And Collateralized Loan Obligations    
Cost or Amortized Cost    
Due in one year or less $ 360.4 $ 455.3
Due after one year through five years 1,635.7 1,349.8
Due after five years through ten years 296.8 199.0
Due after ten years 14.0 21.7
Carrying Value    
Due in one year or less 361.0 455.2
Due after one year through five years 1,623.4 1,354.1
Due after five years through ten years 293.5 199.3
Due after ten years 14.0 21.9
Mortgage and asset-backed securities and collateralized loan obligations    
Cost or Amortized Cost    
Mortgage and asset-backed securities and collateralized loan obligations 764.0 749.0
Carrying Value    
Mortgage and asset-backed securities and collateralized loan obligations 748.0 740.0
Fixed maturity investments    
Cost or Amortized Cost    
Total fixed maturity investments 3,070.9 2,774.8
Carrying Value    
Total fixed maturity investments $ 3,039.9 $ 2,770.5