| Document and Entity Information | Oct. 20, 2020 |
| Document and Entity Information [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Jan. 19, 2021 |
| Entity File Number | 001-37661 |
| Entity Registrant Name | SMARTFINANCIAL, INC. |
| Entity Incorporation, State or Country Code | TN |
| Entity Tax Identification Number | 62-1173944 |
| Entity Address, Address Line One | 5401 Kingston Pike |
| Entity Address, Adress Line Two | Suite 600 |
| Entity Address, City or Town | Knoxville |
| Entity Address, State or Province | TN |
| Entity Address, Postal Zip Code | 37919 |
| City Area Code | 865 |
| Local Phone Number | 437-5700 |
| 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 $1.00 |
| Trading Symbol | SMBK |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001038773 |
| Amendment Flag | false |
