Cover - shares	9 Months Ended
	Sep. 30, 2024	Oct. 31, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2024
Document Transition Report	false
Entity File Number	001-38487
Entity Registrant Name	Origin Bancorp, Inc.
Entity Incorporation, State or Country Code	LA
Entity Tax Identification Number	72-1192928
Entity Address, Address Line One	500 South Service Road East
Entity Address, City or Town	Ruston
Entity Address, State or Province	LA
Entity Address, Postal Zip Code	71270
City Area Code	318
Local Phone Number	255-2222
Title of 12(b) Security	Common Stock, par value $5.00 per share
Trading Symbol	OBK
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		31,168,734
Amendment Flag	false
Current Fiscal Year Focus	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3
Entity CIK	0001516912