XML 321 R65.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Investments - Narrative (Details) - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017
--- | --- | ---
Investment Holdings [Line Items] |  |
Investment grade rating | 95.50% |
Fair value of issued securities | $ 7,515,318 | $ 7,724,075
FHLB funding agreements | 675,000 | 625,000
Limited partnership interests | 328,516 | 247,266
Governmental agencies as required by law in various states |  |
Investment Holdings [Line Items] |  |
Fair value of issued securities | 17,695 | 17,985
FHLB of Chicago |  |
Investment Holdings [Line Items] |  |
Fair value of issued securities | $ 740,016 | $ 686,790

X
- Definition Represents the federal home loan bank funding agreements. + References No definition available. + Details
Name: | hmn_FederalHomeLoanBankFundingAgreements
Namespace Prefix: | hmn_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Percentage of fair value of fixed maturity and equity securities with a gross unrealized loss having an investment grade rating at period end. + References No definition available. + Details
Name: | hmn_InvestmentGradeRate
Namespace Prefix: | hmn_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109979856&loc=d3e26610-111562 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- 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. + References No definition available. + Details
Name: | us-gaap_InvestmentHoldingsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of investment in equity method investee and investment in and advance to affiliate. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.12) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | dei_LegalEntityAxis=hmn_GovernmentalAgenciesAsRequiredByLawInVariousStatesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_FederalHomeLoanBankAdvancesBranchOfFHLBBankAxis=hmn_FederalHomeLoansBankOfChicagoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |