Cover Page - shares	9 Months Ended
	Sep. 30, 2020	Oct. 31, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
Document Transition Report	false
Entity File Number	001-38888
Entity Registrant Name	Red River Bancshares, Inc.
Entity Incorporation, State or Country Code	LA
Entity Tax Identification Number	72-1412058
Entity Address, Address Line One	1412 Centre Court Drive, Suite 501
Entity Address, City or Town	Alexandria
Entity Address, State or Province	LA
Entity Address, Postal Zip Code	71301
City Area Code	318
Local Phone Number	561-5028
Title of 12(b) Security	Common Stock, no par value
Trading Symbol	RRBI
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business Category	true
Entity Emerging Growth Category	true
Entity Ex Transition Period	true
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		7,325,333
Entity Central Index Key	0001071236
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus (i.e. Q1,Q2,Q3,FY)	Q3
Amendment Flag	false