Investments - Additional Information (Details) $ in Millions |
3 Months Ended | 9 Months Ended | |||
|---|---|---|---|---|---|
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Sep. 30, 2026
USD ($)
investment
security
|
Sep. 30, 2025
USD ($)
|
Sep. 30, 2026
USD ($)
investment
security
|
Sep. 30, 2025
USD ($)
|
Dec. 31, 2025
USD ($)
|
|
| Net Investment Income [Line Items] | |||||
| Gross unrealized losses (less than for December 31, 2025) | $ 12.8 | $ 12.8 | $ 0.0 | ||
| Pre-tax net realized capital gains (losses) | $ 0.2 | $ (0.2) | $ (0.3) | $ 0.3 | |
| Number of debt securities held, unrealized loss position | security | 576 | 576 | |||
| Debt securities, available-for-sale | investment | 3 | 3 | |||
| Gross unrealized losses, twelve months or more | $ 0.0 | $ 0.0 | 0.0 | ||
| Restricted investments | 53.2 | 53.2 | 81.5 | ||
| Financing receivable, allowance for credit loss | 0.0 | 0.0 | |||
| Fixed Income Securities | |||||
| Net Investment Income [Line Items] | |||||
| Gross unrealized losses (less than for December 31, 2025) | 12.8 | 12.8 | 0.1 | ||
| Gross unrealized losses, twelve months or more | $ 0.1 | $ 0.1 | $ 0.1 | ||
| X | ||||||||||
- Definition Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset. Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
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- Definition Number of investments in debt securities measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without an allowance for credit loss. Includes beneficial interest in securitized financial asset. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Number of investments in debt securities measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset. Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
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- Definition Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of realized gain (loss) on investment. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Investments which are not defined as or included in marketable (debt, equity, or other) securities whose use is restricted in whole or in part, generally by contractual agreements or regulatory requirements. For use in an unclassified balance sheet. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Details
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