v3.25.2
Cover - shares
6 Months Ended
Jun. 30, 2025
Jul. 31, 2025
Cover [Abstract]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Jun. 30, 2025  
Document Transition Report false  
Entity File Number 001-37875  
Entity Registrant Name FB FINANCIAL CORPORATION  
Entity Incorporation, State or Country Code TN  
Entity Tax Identification Number 62-1216058  
Entity Address, Address Line One 1221 Broadway  
Entity Address, Address Line Two Suite 1300  
Entity Address, City or Town Nashville  
Entity Address, State or Province TN  
Entity Address, Postal Zip Code 37203  
City Area Code 615  
Local Phone Number 564-1212  
Title of 12(b) Security Common Stock, Par Value $1.00 Per Share  
Trading Symbol FBK  
Security Exchange Name NYSE  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Large Accelerated Filer  
Entity Small Reporting Company false  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   53,848,882
Amendment Flag false  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus Q2  
Entity Central Index Key 0001649749  
Current Fiscal Year End Date --12-31