| Document and Entity Information | Oct. 14, 2022 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001781730 |
| Document Type | 8-K |
| Document Period End Date | Oct. 14, 2022 |
| Entity Registrant Name | THIRD COAST BANCSHARES, INC. |
| Entity Incorporation State Country Code | TX |
| Entity File Number | 001-41028 |
| Entity Tax Identification Number | 46-2135597 |
| Entity Address, Address Line One | 20202 Highway 59 North |
| Entity Address, Address Line Two | Suite 190 |
| Entity Address, City or Town | Humble |
| Entity Address, State or Province | TX |
| Entity Address, Postal Zip Code | 77338 |
| City Area Code | (281) |
| Local Phone Number | 446-7000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common stock, par value $1.00 per share |
| Trading Symbol | TCBX |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
