Fair Value of Financial Instruments (Details Textual) (Level 3 [Member])	Mar. 31, 2014
Level 3 [Member]
Fair Value of Financial Instruments (Textual) [Abstract]
Percentage of investment portfolio fair value pricing services or index priced	88.00%
Percentage of invested assets in total investment portfolio level3	1.80%

Percentage of investment portfolio fair value priced through pricing services or index priced.

No definition available.

Name:	hmn_PercentageOfInvestmentPortfolioFairValuePricingServicesOrIndexPriced
Namespace Prefix:	hmn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant