Investments (Investments Pledged as Collateral) (Details) $ in Millions	Dec. 31, 2020 USD ($)
Available-for-sale Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Assets Held by Insurance Regulators	$ 25.2
Securities pledged as collateral for reinsurance obligations	371.6
U.S. Government and Government Agencies [Member]
Debt Securities, Available-for-sale [Line Items]
Assets Held by Insurance Regulators	20.1
Securities pledged as collateral for reinsurance obligations	20.1
Obligations of States and Political Subdivisions [Member]
Debt Securities, Available-for-sale [Line Items]
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	0.0
Assets Held by Insurance Regulators	5.1
Securities pledged as collateral for reinsurance obligations	5.1
Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Assets Held by Insurance Regulators	0.0
Securities pledged as collateral for reinsurance obligations	303.1
Commercial Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Assets Held by Insurance Regulators	0.0
Securities pledged as collateral for reinsurance obligations	43.3
Federal Home Loan Bank of New York [Member] \| Available-for-sale Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	214.4
Federal Home Loan Bank of New York [Member] \| U.S. Government and Government Agencies [Member]
Debt Securities, Available-for-sale [Line Items]
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	0.0
Federal Home Loan Bank of New York [Member] \| Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	178.1
Federal Home Loan Bank of New York [Member] \| Commercial Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	36.3
Federal Home Loan Bank of Indianapolis [Member] \| Available-for-sale Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	132.0
Federal Home Loan Bank of Indianapolis [Member] \| U.S. Government and Government Agencies [Member]
Debt Securities, Available-for-sale [Line Items]
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	0.0
Federal Home Loan Bank of Indianapolis [Member] \| Obligations of States and Political Subdivisions [Member]
Debt Securities, Available-for-sale [Line Items]
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	0.0
Federal Home Loan Bank of Indianapolis [Member] \| Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	125.0
Federal Home Loan Bank of Indianapolis [Member] \| Commercial Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	$ 7.0

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=75763970&loc=SL75763979-209797

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Amount of the collateral pledged in support of federal home loan bank advances outstanding.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822

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+ References

No definition available.

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+ 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

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=66007379&loc=d3e113888-111728

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