Investment Securities - Investments Held on Deposit or as Collateral (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Investment securities
Investments held in trusts	$ 479.5	$ 432.4
Assets held by insurance regulators	$ 4.8	$ 11.9
Percentage of investments recorded at fair value	68.00%	73.00%
Lloyds Bank
Investment securities
Investments held in trusts	$ 113.8
Fair value investments	342.8
Short-term investments
Investment securities
Investments pledged as collateral	$ 50.0

Carrying amount of cash and investment securities on deposit with state regulatory authorities in connection with capital requirements.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 825
-Section 50
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=123600598&loc=SL75763979-209797

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Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
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Fair value of financial instrument held by the entity for its own account (proprietary securities) for trading or investment purposes that are carried at fair value and pledged to counterparties as collateral for financing transactions.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 50
-Paragraph 1A
-Subparagraph (b)(1)(i)
-URI http://asc.fasb.org/extlink&oid=109249958&loc=SL6224234-111729

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 45
-Paragraph 1
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Investments Held In Trusts

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Represents the percentage of the total investment portfolio recorded at fair value based upon quoted market prices or other observable inputs.

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