| Document And Entity Information | Jan. 27, 2022 |
| Document Information [Line Items] | |
| Entity, Registrant Name | HMN Financial, Inc. |
| Document, Type | 8-K |
| Document, Period End Date | Jan. 27, 2022 |
| Entity, Incorporation, State or Country Code | DE |
| Entity, File Number | 0-24100 |
| Entity, Tax Identification Number | 41-1777397 |
| Entity, Address, Address Line One | 1016 Civic Center Drive Northwest |
| Entity, Address, City or Town | Rochester |
| Entity, Address, State or Province | MN |
| Entity, Address, Postal Zip Code | 55901 |
| City Area Code | 507 |
| Local Phone Number | 535-1200 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock |
| Trading Symbol | HMNF |
| Security Exchange Name | NASDAQ |
| Entity, Emerging Growth Company | false |
| Amendment Flag | false |
| Entity, Central Index Key | 0000921183 |
