Note 5 - Loans Receivable, Net (Details Textual) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Receivable Loans and Leases, Commitments to Originate or Purchase Loans	$ 13,183	$ 24,692
Loans and Leases Receivable, Related Parties, Ending Balance	100	100	$ 200
Loans and Leases Receivable, Related Parties, Loans Reclassified		100	2,500
Servicing Liability for Others, Unpaid Principal Balance	480,600	471,400	$ 425,500
Fixed Rate Loans [Member]
Receivable Loans and Leases, Commitments to Originate or Purchase Loans	$ 11,000	$ 18,100
Fixed Rate Loans [Member] \| Minimum [Member]
Receivable Loans and Leases, Commitments Interest Percentage	4.125%	3.375%
Fixed Rate Loans [Member] \| Maximum [Member]
Receivable Loans and Leases, Commitments Interest Percentage	6.375%	5.21%

Amount of loans to related parties that were reclassified during the period.

No definition available.

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

- Definition

Interest rates on fixed rate loans included in total commitments to originate or purchase loans.

+ References

No definition available.

+ Details

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

- Definition

Value of fixed rate loans included in total commitments to originate or purchase loans.

+ References

No definition available.

+ Details

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

- Definition

Value of the unpaid principal balances for the liability for loans serviced for others.

+ References

No definition available.

+ Details

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

- Definition

For an unclassified balance sheet, reflects the carrying amount of unpaid loan amounts due from related parties at the balance sheet date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(e))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=hmnf_FixedRateLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: