| Document and Entity Information | Feb. 14, 2022 |
| Document and Entity Information [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Feb. 14, 2022 |
| Entity File Number | 001-39085 |
| Entity Registrant Name | HBT FINANCIAL, INC. |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 37-1117216 |
| Entity Address, Address Line One | 401 North Hershey Road |
| Entity Address, City or Town | Bloomington |
| Entity Address State Or Province | IL |
| Entity Address, Postal Zip Code | 61704 |
| City Area Code | 888 |
| Local Phone Number | 897-2276 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, par value $0.01 per share |
| Trading Symbol | HBT |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Entity Central Index Key | 0000775215 |
| Amendment Flag | false |
