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Investment Securities (Investments Held on Deposit or as Collateral) (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2019 | Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract] |  |
Investments held in trusts | $ 319.9 | $ 254.3
Assets held by insurance regulators | $ 9.9 | $ 6.1
Percentage of investments recorded at fair value | 71.00% | 87.00%

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- Definition Carrying amount of cash and investment securities on deposit with state regulatory authorities in connection with capital requirements. + References 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=75763970&loc=SL75763979-209797 + Details
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- References No definition available. + Details
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- Definition Investments Held In Trusts + References No definition available. + Details
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- Definition Represents the percentage of the total investment portfolio recorded at fair value based upon quoted market prices or other observable inputs. + References No definition available. + Details
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