Investments - Additional Information (Details) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2022 USD ($) security	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($) security	Jun. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)
Investments, Debt and Equity Securities [Abstract]
Gross unrealized losses	$ 24.3		$ 24.3		$ 5.5
Realized investment gains (losses) (less than for three and six months ended June 30, 2022)	$ (0.4)	$ 0.0	$ (0.4)	$ 0.0
Number of debt securities held, unrealized loss position \| security	287		287

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).

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (b)(3)
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27290-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
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Amount of realized gain (loss) on investment.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
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-URI https://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263

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