Stockholders' Equity (Tables)

9 Months Ended

Sep. 30, 2012

Stockholders' Equity [Abstract]

Summary of shares repurchased under stock purchase program

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2012		2011		2012		2011
Number of shares repurchased		—		162,890		6,787		280,066
Average price of shares repurchased		—	$	34.56	$	37.70	$	35.89
Shares remaining to be repurchased		—		263,834		234,964		263,834

Required capital amounts and the Company's respective ratios

	Actual					For Capital Adequacy Purposes					To Be Well Capitalized Under Prompt Corrective Action Provisions
	Amount		Ratio			Amount		Ratio			Amount		Ratio
	(Dollars in thousands)
As of September 30, 2012:
Total Capital
(to Risk Weighted Assets)-
BancFirst Corporation	$	510,604		14.74	%	$	277,168		8.00	%		N/A		N/A
BancFirst		485,030		14.04	%		276,288		8.00	%	$	345,360		10.00	%
Tier 1 Capital
(to Risk Weighted Assets)-
BancFirst Corporation	$	473,346		13.66	%	$	138,584		4.00	%		N/A		N/A
BancFirst		447,772		12.97	%		138,144		4.00	%	$	207,216		6.00	%
Tier 1 Capital
(to Total Assets)-
BancFirst Corporation	$	473,346		8.19	%	$	175,150		3.00	%		N/A		N/A
BancFirst		447,772		7.76	%		174,503		3.00	%	$	290,839		5.00	%