Fair Value Measurements - Fair Value Hierarchy for Financial Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Financial Assets:
Fixed maturities	$ 650.3	$ 691.4
Short term investments	99.8	110.4
Total Financial Assets	750.1	801.8
Corporate debt securities
Financial Assets:
Fixed maturities	530.2	588.7
U.S. Government obligations
Financial Assets:
Fixed maturities	117.3	101.5
Asset-backed securities
Financial Assets:
Fixed maturities	2.8	0.0
Municipal securities
Financial Assets:
Fixed maturities	0.0	1.2
Warrant liability
Financial Liabilities:
Warrant liability	0.3	0.0
Level 1
Financial Assets:
Fixed maturities	0.0	0.0
Short term investments	0.0	0.0
Total Financial Assets	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 \| Municipal securities
Financial Assets:
Fixed maturities	0.0	0.0
Level 1 \| Warrant liability
Financial Liabilities:
Warrant liability	0.0	0.0
Level 2
Financial Assets:
Fixed maturities	650.3	691.4
Short term investments	99.8	110.4
Total Financial Assets	750.1	801.8
Level 2 \| Corporate debt securities
Financial Assets:
Fixed maturities	530.2	588.7
Level 2 \| U.S. Government obligations
Financial Assets:
Fixed maturities	117.3	101.5
Level 2 \| Asset-backed securities
Financial Assets:
Fixed maturities	2.8	0.0
Level 2 \| Municipal securities
Financial Assets:
Fixed maturities	0.0	1.2
Level 2 \| Warrant liability
Financial Liabilities:
Warrant liability	0.0	0.0
Level 3
Financial Assets:
Fixed maturities	0.0	0.0
Short term investments	0.0	0.0
Total Financial Assets	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 \| Municipal securities
Financial Assets:
Fixed maturities	0.0	0.0
Level 3 \| Warrant liability
Financial Liabilities:
Warrant liability	$ 0.3	$ 0.0

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Fair Value Disclosure, Financial Liabilities

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Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of investments including trading securities, available-for-sale securities, held-to-maturity securities, and short-term investments classified as other and current.

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