v3.26.1
Fair Value Measurements - Fair Value Hierarchy for Financial Assets and Liabilities (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturities $ 731.8 $ 708.8
Short term investments 19.5 14.1
Total 751.3 722.9
Fair value of warrant liability (less than)   0.1
Corporate debt securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturities 490.9 501.2
U.S. Government obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturities 163.1 140.1
Asset-backed securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturities 50.7 45.5
Non-U.S. government obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturities 27.1 22.0
Warrant Liability    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Warrant Liability   0.0
Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturities 0.0 0.0
Short term investments 0.0 0.0
Total 0.0 0.0
Level 1 | Corporate debt securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturities 0.0 0.0
Level 1 | U.S. Government obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturities 0.0 0.0
Level 1 | Asset-backed securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturities 0.0 0.0
Level 1 | Non-U.S. government obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturities 0.0 0.0
Level 1 | Warrant Liability    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Warrant Liability   0.0
Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturities 731.8 708.8
Short term investments 19.5 14.1
Total 751.3 722.9
Level 2 | Corporate debt securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturities 490.9 501.2
Level 2 | U.S. Government obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturities 163.1 140.1
Level 2 | Asset-backed securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturities 50.7 45.5
Level 2 | Non-U.S. government obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturities 27.1 22.0
Level 2 | Warrant Liability    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Warrant Liability   0.0
Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturities 0.0 0.0
Short term investments 0.0 0.0
Total 0.0 0.0
Level 3 | Corporate debt securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturities 0.0 0.0
Level 3 | U.S. Government obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturities 0.0 0.0
Level 3 | Asset-backed securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturities 0.0 0.0
Level 3 | Non-U.S. government obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturities $ 0.0 0.0
Level 3 | Warrant Liability    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Warrant Liability   $ 0.0