| Document and Entity Information | May 19, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | May 19, 2021 |
| Current Fiscal Year End Date | --12-31 |
| Entity Registrant Name | LIMESTONE BANCORP, INC. |
| Entity Incorporation, State or Country Code | KY |
| Entity File Number | 001-33033 |
| Entity Tax Identification Number | 61-1142247 |
| Entity Address, Address Line One | 2500 Eastpoint Parkway |
| Entity Address, City or Town | Louisville |
| Entity Address, State or Province | KY |
| Entity Address, Postal Zip Code | 40223 |
| City Area Code | 502 |
| Local Phone Number | 499-4800 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001358356 |
| Title of 12(b) Security | Common shares |
| Trading Symbol | LMST |
| Security Exchange Name | NASDAQ |
