Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2017

Equity [Abstract]

Summary of Authorized Outstanding Preferred and Common Stock

As of December 31, 2017, 2016 and 2015 the Company’s authorized and outstanding preferred and common stock was as follows:

	No. of Shares Authorized at		No. of Shares Outstanding at December 31,
Class of Stock	December 31, 2017		2017		2016		2015		Par Value Per Share		Dividends	Voting Rights
Senior Preferred		10,000,000		—		—		—	$	1.00	As declared	Voting
10% Cumulative Preferred		900,000		—		—		—		5.00	As declared	Non-voting
Common		40,000,000		31,894,563		31,621,870		31,194,892		1.00	As declared	Voting

Summary of Shares Repurchased Under Stock Purchase Program

The following table is a summary of the shares under the program:

	Year Ended December 31,
	2017		2016		2015
Number of shares repurchased		—		200,000		56,894
Average price of shares repurchased	$	—	$	27.62	$	29.10
Shares remaining to be repurchased		300,000		300,000		332,552

Required Capital Amounts and Company's Respective Ratios

The actual and required capital amounts and ratios are shown in the following table:

						Required									To Be Well
						For Capital				With					Capitalized Under
						Adequacy				Capital Conservation					Prompt Corrective
	Actual					Purposes				Buffer					Action Provisions
	Amount		Ratio			Amount		Ratio		Amount		Ratio			Amount		Ratio
	(Dollars in thousands)
As of December 31, 2017:
Total Capital
(to Risk Weighted Assets)-
BancFirst Corporation	$	797,015		15.62	%	$	408,234		8.00%	$	472,020		9.250	%	N/A		N/A
BancFirst		714,964		14.03	%		407,698		8.00%		471,401		9.250	%	$	509,622		10.00	%
Common Equity Tier 1 Capital
(to Risk Weighted Assets)-
BancFirst Corporation	$	714,349		14.00	%	$	229,632		4.50%	$	293,418		5.750	%	N/A		N/A
BancFirst		643,298		12.62	%		229,330		4.50%		293,033		5.750	%	$	331,255		6.50	%
Tier 1 Capital
(to Risk Weighted Assets)-
BancFirst Corporation	$	745,349		14.61	%	$	306,175		6.00%	$	369,962		7.250	%	N/A		N/A
BancFirst		663,298		13.02	%		306,773		6.00%		369,476		7.250	%	$	407,698		8.00	%
Tier 1 Capital
(to Total Assets)-
BancFirst Corporation	$	745,349		10.44	%	$	285,444		4.00%	N/A		N/A			N/A		N/A
BancFirst		663,298		9.31	%		285,101		4.00%	N/A		N/A			$	356,677		5.00	%
As of December 31, 2016:
Total Capital
(to Risk Weighted Assets)-
BancFirst Corporation	$	728,635		15.33	%	$	380,351		8.00%	$	410,066		8.625	%	N/A		N/A
BancFirst		655,620		13.80	%		379,948		8.00%		409,631		8.625	%	$	474,934		10.00	%
Common Equity Tier 1 Capital
(to Risk Weighted Assets)-
BancFirst Corporation	$	648,942		13.65	%	$	213,947		4.50%	$	243,662		5.125	%	N/A		N/A
BancFirst		586,927		12.36	%		213,720		4.50%		243,404		5.125	%	$	308,707		6.50	%
Tier 1 Capital
(to Risk Weighted Assets)-
BancFirst Corporation	$	679,942		14.30	%	$	285,263		6.00%	$	314,978		6.625	%	N/A		N/A
BancFirst		606,927		12.78	%		284,961		6.00%		314,644		6.625	%	$	379,948		8.00	%
Tier 1 Capital
(to Total Assets)-
BancFirst Corporation	$	679,942		9.94	%	$	273,510		4.00%	N/A		N/A			N/A		N/A
BancFirst		606,927		8.89	%		273,152		4.00%	N/A		N/A			$	341,440		5.00	%