Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2022	Jul. 31, 2022
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q2
Trading Symbol	BANF
Entity Registrant Name	BancFirst Corporation
Entity Central Index Key	0000760498
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, $1.00 Par Value Per Share
Security Exchange Name	NASDAQ
Entity File Number	0-14384
Entity Incorporation, State or Country Code	OK
Entity Tax Identification Number	73-1221379
Entity Address, Address Line One	100 N. Broadway Ave.
Entity Address, City or Town	Oklahoma City
Entity Address, State or Province	OK
Entity Address, Postal Zip Code	73102-8405
City Area Code	405
Local Phone Number	270-1086
Document Quarterly Report	true
Document Transition Report	false
Entity Common Stock, Shares Outstanding		32,787,596