Note 20 - Fair Value Measurements - Assets Measured at Fair Value on Nonrecurring Basis (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Loans held for sale, Total gains (losses)	$ (56)	$ 28
Mortgage servicing rights, Total gains (losses)	0	0
Impaired loanss, Total gains (losses)	(218)	(76)
Real estate, net, Total gains (losses)	0	0
Total, Total gains (losses)	(274)	(48)
Fair Value, Nonrecurring [Member]
Loans held for sale	5,575	6,186
Mortgage servicing rights, net	3,280	3,043
Impaired loans	4,244	2,888
Real estate, net	290	636
Total	13,389	12,753
Real estate, net	290	636
Fair Value, Nonrecurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Loans held for sale	0	0
Mortgage servicing rights, net	0	0
Impaired loans	0	0
Real estate, net	0	0
Total	0	0
Real estate, net	0	0
Fair Value, Nonrecurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Loans held for sale	5,575	6,186
Mortgage servicing rights, net	3,280	3,043
Impaired loans	4,244	2,888
Real estate, net	290	636
Total	13,389	12,753
Real estate, net	290	636
Fair Value, Nonrecurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Loans held for sale	0	0
Mortgage servicing rights, net	0	0
Impaired loans	0	0
Real estate, net	0	0
Total	0	0
Real estate, net	$ 0	$ 0

Represents the amount of gain (loss) on fair value adjustments of loans during the period.

No definition available.

Name:	hmnf_GainLossOnFairValueAdjustmentsOfLoans
Namespace Prefix:	hmnf_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the amount of gain (loss) on fair value adjustments of loans held for sale during the period.

+ References

No definition available.

+ Details

Name:	hmnf_GainLossOnFairValueAdjustmentsOfLoansHeldForSale
Namespace Prefix:	hmnf_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the amount of gain (loss) on fair value adjustments of mortgage servicing rights during the period.

+ References

No definition available.

+ Details

Name:	hmnf_GainLossOnFairValueAdjustmentsOfMortgageServicingRights
Namespace Prefix:	hmnf_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the amount of gain (loss) on fair value adjustments of repossessed assets during the period.

+ References

No definition available.

+ Details

Name:	hmnf_GainLossOnFairValueAdjustmentsOfRepossessedAssets
Namespace Prefix:	hmnf_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the fair value portion of loans receivable adjustments based on appraised value of collateral.

+ References

No definition available.

+ Details

Name:	hmnf_LoansReceivableAdjustmentsBasedOnAppraisedValueOfCollateralFairValueDisclosure
Namespace Prefix:	hmnf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the fair value portion of repossessed assets.

+ References

No definition available.

+ Details

Name:	hmnf_RepossessedAssetsFairValueDisclosure
Namespace Prefix:	hmnf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

+ Details

Name:	us-gaap_AssetsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of gain (loss) from the difference between the sale price or salvage price and the book value of an asset that was sold or retired, and gain (loss) from the write down of assets from their carrying value to fair value.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3602-108585

+ Details

Name:	us-gaap_GainLossOnSalesOfAssetsAndAssetImpairmentCharges
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

+ References

No definition available.

+ Details

Name:	us-gaap_LoansHeldForSaleFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 45
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6469459&loc=d3e122501-111745

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6469459&loc=d3e122492-111745

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=125521744&loc=d3e122625-111746

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 45
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6469459&loc=d3e122501-111745

+ Details

Name:	us-gaap_ServicingAssetAtFairValueAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsNonrecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: