v3.26.1
Document and Entity Information - shares
 3 Months Ended
Mar. 31, 2026
Apr. 30, 2026
Document Information [Line Items]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Mar. 31, 2026  
Document Fiscal Year Focus 2026  
Document Fiscal Period Focus Q1  
Entity Registrant Name THIRD COAST BANCSHARES, INC.  
Entity Central Index Key 0001781730  
Current Fiscal Year End Date --12-31  
Entity Filer Category Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company true  
Entity Ex Transition Period false  
Entity Shell Company false  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Incorporation, State or 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  
Document Quarterly Report true  
Document Transition Report false  
Entity Common Stock, Shares Outstanding   16,592,071
New York Stock Exchange    
Document Information [Line Items]    
Title of 12(b) Security Common Stock, par value $1.00 per share  
Trading Symbol TCBX  
Security Exchange Name NYSE  
NYSE Texas    
Document Information [Line Items]    
Title of 12(b) Security Common Stock, par value $1.00 per share  
Trading Symbol TCBX  
Security Exchange Name CHX