| Document and Entity Information | Apr. 28, 2021 |
| Document and Entity Information [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Apr. 28, 2021 |
| Entity Registrant Name | Hawthorn Bancshares, Inc. |
| Entity Incorporation, State or Country Code | MO |
| Entity File Number | 0-23636 |
| Entity Tax Identification Number | 43-1626350 |
| Entity Address, Address Line One | 132 East High Street |
| Entity Address, Adress Line Two | PO Box 688 |
| Entity Address, City or Town | Jefferson City |
| Entity Address, State or Province | MO |
| Entity Address, Postal Zip Code | 65102 |
| City Area Code | 573 |
| Local Phone Number | 761-6100 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $1.00 par value |
| Trading Symbol | HWBK |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0000893847 |
| Amendment Flag | false |
