Short-Duration Insurance Contracts - Average Annual Percentage Payout Of Incurred Claims by Age (Details)	Dec. 31, 2025
Homeowners
2025
Year One	78.50%
Year Two	18.60%
Year Three	2.20%
Year Four	0.50%
Year Five	0.20%
Year Six	0.00%
Year Seven	0.00%
Year Eight	0.00%
Year Nine	0.00%
Year Ten	0.00%
Automobile Liability
2025
Year One	37.10%
Year Two	35.60%
Year Three	15.00%
Year Four	6.70%
Year Five	3.30%
Year Six	1.60%
Year Seven	0.50%
Year Eight	0.10%
Year Nine	0.10%
Year Ten	0.00%
Auto physical damage
2025
Year One	95.00%
Year Two	5.30%
Year Three	(0.30%)
Year Four	0.00%
Year Five	0.00%
Year Six	0.00%
Year Seven	0.00%
Year Eight	0.00%
Year Nine	0.00%
Year Ten	0.00%
Specialty Health
2025
Year One	61.30%
Year Two	35.10%
Year Three	2.20%
Year Four	1.40%
Year Five	0.00%
Year Six	0.00%
Year Seven	0.00%
Year Eight	0.00%
Year Nine	0.00%
Year Ten	0.00%
Group Disability
2025
Year One	30.20%
Year Two	32.30%
Year Three	9.40%
Year Four	3.80%
Year Five	3.20%
Year Six	2.90%
Year Seven	2.70%
Year Eight	2.20%
Year Nine	1.90%
Year Ten	1.80%

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.

Name:	us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of average annual payout, after reinsurance, in the eighth year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 55
-Paragraph 9F
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480046/944-40-55-9F

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 4G
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480081/944-40-50-4G

+ Details

Name:	us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearEight
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of average annual payout, after reinsurance, in the fifth year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.

+ References

+ Details

Name:	us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearFive
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of average annual payout, after reinsurance, in the fourth year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.

+ References

+ Details

Name:	us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearFour
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of average annual payout, after reinsurance, in the ninth year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.

+ References

+ Details

Name:	us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearNine
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of average annual payout, after reinsurance, in the first year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.

+ References

+ Details

Name:	us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearOne
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of average annual payout, after reinsurance, in the seventh year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.

+ References

+ Details

Name:	us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearSeven
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of average annual payout, after reinsurance, in the sixth year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.

+ References

+ Details

Name:	us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearSix
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of average annual payout, after reinsurance, in the tenth year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.

+ References

+ Details

Name:	us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearTen
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of average annual payout, after reinsurance, in the third year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.

+ References

+ Details

Name:	us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearThree
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of average annual payout, after reinsurance, in the second year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.

+ References

+ Details

Name:	us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearTwo
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	srt_ProductOrServiceAxis=hmn_HomeownersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=hmn_AutoLiabilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=hmn_AutoPhysicalDamageNettingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=hmn_SpecialityHealthMemberMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=hmn_GroupDisabilityMemberMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: