Fair Value Measurements - Fair Value Hierarchy for Financial Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Financial Assets:
Fixed maturities	$ 708.8	$ 607.4
Short term investments	14.1	27.5
Total	722.9	634.9
Fair value of warrant liability (less than)	0.1	0.1
Corporate debt securities
Financial Assets:
Fixed maturities	501.2	470.8
U.S. Government obligations
Financial Assets:
Fixed maturities	140.1	107.7
Asset-backed securities
Financial Assets:
Fixed maturities	45.5	22.9
Non-U.S. government obligations
Financial Assets:
Fixed maturities	22.0	6.0
Warrant liability
Financial Assets:
Warrant liability	0.0	0.0
Level 1
Financial Assets:
Fixed maturities	0.0	0.0
Short term investments	0.0	0.0
Total	0.0	0.0
Level 1 \| Corporate debt securities
Financial Assets:
Fixed maturities	0.0	0.0
Level 1 \| U.S. Government obligations
Financial Assets:
Fixed maturities	0.0	0.0
Level 1 \| Asset-backed securities
Financial Assets:
Fixed maturities	0.0	0.0
Level 1 \| Non-U.S. government obligations
Financial Assets:
Fixed maturities	0.0	0.0
Level 1 \| Warrant liability
Financial Assets:
Warrant liability	0.0	0.0
Level 2
Financial Assets:
Fixed maturities	708.8	607.4
Short term investments	14.1	27.5
Total	722.9	634.9
Level 2 \| Corporate debt securities
Financial Assets:
Fixed maturities	501.2	470.8
Level 2 \| U.S. Government obligations
Financial Assets:
Fixed maturities	140.1	107.7
Level 2 \| Asset-backed securities
Financial Assets:
Fixed maturities	45.5	22.9
Level 2 \| Non-U.S. government obligations
Financial Assets:
Fixed maturities	22.0	6.0
Level 2 \| Warrant liability
Financial Assets:
Warrant liability	0.0	0.0
Level 3
Financial Assets:
Fixed maturities	0.0	0.0
Short term investments	0.0	0.0
Total	0.0	0.0
Level 3 \| Corporate debt securities
Financial Assets:
Fixed maturities	0.0	0.0
Level 3 \| U.S. Government obligations
Financial Assets:
Fixed maturities	0.0	0.0
Level 3 \| Asset-backed securities
Financial Assets:
Fixed maturities	0.0	0.0
Level 3 \| Non-U.S. government obligations
Financial Assets:
Fixed maturities	0.0	0.0
Level 3 \| Warrant liability
Financial Assets:
Warrant liability	$ 0.0	$ 0.0

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Fair value of financial and nonfinancial obligations.

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