Document and Entity Information - shares
3 Months Ended
Mar. 31, 2019
May 31, 2019
Document and Entity Information [Abstract]    
Entity Registrant Name Red River Bancshares Inc  
Entity Central Index Key 0001071236  
Current Fiscal Year End Date --12-31  
Entity Filer Category Non-accelerated Filer  
Document Type 10-Q  
Document Period End Date Mar. 31, 2019  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus (i.e. Q1,Q2,Q3,FY) Q1  
Amendment Flag false  
Entity Common Stock, Shares Outstanding   7,300,246
Entity Emerging Growth Category true  
Entity Small Business Category true  
Entity Ex Transition Period true