Name:	hmnf_DefinedContributionPlanEmployerContributionPercentOfAnnualSalaryOfEmployee
Namespace Prefix:	hmnf_
Data Type:	num:percentItemType
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Period Type:	duration

Represents the number of additional shares purchased under an employee stock ownership plan (ESOP).

No definition available.

Name:	hmnf_EmployeeStockOwnershipPlanEsopAdditionalSharesPurchased
Namespace Prefix:	hmnf_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Represents the debt structure direct original loan amount under an employee stock ownership plan (ESOP).

No definition available.

Name:	hmnf_EmployeeStockOwnershipPlanEsopDebtStructureDirectOriginalLoanAmount
Namespace Prefix:	hmnf_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Represents the debt structure indirect original loan amount under an employee stock ownership (ESOP).

No definition available.

Name:	hmnf_EmployeeStockOwnershipPlanEsopDebtStructureIndirectOriginalLoanAmount
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Represents the interest rate on a loan under an employee stock ownership plan (ESOP).

No definition available.

Name:	hmnf_EmployeeStockOwnershipPlanEsopInterestRateOnLoan
Namespace Prefix:	hmnf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Represents the number of shares repurchased under an employee stock ownership plan (ESOP).

No definition available.

Name:	hmnf_EmployeeStockOwnershipPlanEsopSharesPurchased
Namespace Prefix:	hmnf_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Represents the maximum contribution percent by participant.

No definition available.

Name:	hmnf_MaximumContributionPercentByParticipant
Namespace Prefix:	hmnf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Represents the minimum age required to be eligible to participate in the entity's defined contribution plan.

No definition available.

Name:	hmnf_MinimumAgeRequiredForDefinedContributionPlanEligibility
Namespace Prefix:	hmnf_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Represents the minimum age required to be eligible to participate in employee stock option option plan.

No definition available.

Name:	hmnf_MinimumAgeRequiredToBeEligibleToParticipateInEmployeeStockOptionOptionPlan
Namespace Prefix:	hmnf_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Represents the number of shares as which each share of restricted stock is counted for purposes of determining total shares available for issuance under a compensation plan.

No definition available.

Name:	hmnf_SharesAvailableForIssuanceNumberOfSharesForEachShareOfRestrictedStock
Namespace Prefix:	hmnf_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

Amount of contribution received by defined benefit plan from employer which increases plan assets.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
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Name:	us-gaap_DefinedBenefitPlanContributionsByEmployer
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Percentage of plan assets to benefit obligation of defined benefit plan.

No definition available.

Name:	us-gaap_DefinedBenefitPlanFundedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Amount of cost for defined contribution plan.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

No definition available.

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Maximum amount the employee may contribute to a defined contribution plan.

No definition available.

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Data Type:	xbrli:monetaryItemType
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Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan.

No definition available.

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Data Type:	num:percentItemType
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Period Type:	duration

This item represents the amount of cash contributions during the period made by the entity to the Employee Stock Ownership Plan (ESOP).

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Data Type:	xbrli:monetaryItemType
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The amount of plan compensation cost recognized during the period.

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Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Data Type:	xbrli:durationItemType
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Period Type:	duration

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

Gross number of share options (or share units) granted during the period.

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Number of options outstanding, including both vested and non-vested options.

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Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

Number of fully vested and expected to vest options outstanding that can be converted into shares under option plan. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Data Type:	xbrli:sharesItemType
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Period Type:	instant

Weighted-average exercise price, at which grantee can acquire shares reserved for issuance, for fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice
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Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Number of non-vested options outstanding.

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

Name:	us-gaap_AwardTypeAxis=us-gaap_RestrictedStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_PlanNameAxis=hmnf_The2009PlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_PlanNameAxis=hmnf_The2017PlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: