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Fair Value Measurements - Fair Value Hierarchy for Financial Assets and Liabilities (Details) - USD ($) $ in Millions | Jun. 30, 2026 | Dec. 31, 2025
--- | --- | ---
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Fixed maturities | $ 768.5 | $ 708.8
Short term investments | 9.2 | 14.1
Total | 777.7 | 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 | 501.4 | 501.2
U.S. Government obligations |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Fixed maturities | 156.0 | 140.1
Asset-backed securities and collateralized loan obligations |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Fixed maturities | 82.2 |
Non-U.S. government obligations |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Fixed maturities | 28.9 | 22.0
Asset-backed securities |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Fixed maturities | 82.2 | 45.5
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 and collateralized loan obligations |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Fixed maturities | 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 | Asset-backed securities |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Fixed maturities |  | 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 | 768.5 | 708.8
Short term investments | 9.2 | 14.1
Total | 777.7 | 722.9
Level 2 | Corporate debt securities |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Fixed maturities | 501.4 | 501.2
Level 2 | U.S. Government obligations |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Fixed maturities | 156.0 | 140.1
Level 2 | Asset-backed securities and collateralized loan obligations |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Fixed maturities | 82.2 |
Level 2 | Non-U.S. government obligations |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Fixed maturities | 28.9 | 22.0
Level 2 | Asset-backed securities |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Fixed maturities |  | 45.5
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 and collateralized loan obligations |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Fixed maturities | 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 | Asset-backed securities |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Fixed maturities |  | 0.0
Level 3 | Warrant Liability |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Warrant Liability |  | $ 0.0

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