Description of Business and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2015
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited interim consolidated financial statements include the accounts of BancFirst Corporation, Council Oak Partners, LLC, BancFirst Insurance Services, Inc. and BancFirst and its subsidiaries. The principal operating subsidiaries of BancFirst are Council Oak Investment Corporation, Council Oak Real Estate, Inc. and BancFirst Agency, Inc. All significant intercompany accounts and transactions have been eliminated. Assets held in a fiduciary or agency capacity are not assets of the Company and, accordingly, are not included in the unaudited interim consolidated financial statements. The accompanying unaudited interim consolidated financial statements and notes are presented in accordance with the instructions for Form 10-Q. The information contained in the financial statements and footnotes included in BancFirst Corporation’s Annual Report on Form 10-K for the year ended December 31, 2014, should be referred to in connection with these unaudited interim consolidated financial statements. Operating results for the interim periods disclosed herein are not necessarily indicative of the results that may be expected for a full year or any future period. The unaudited interim consolidated financial statements contained herein reflect all adjustments which are, in the opinion of management, necessary to provide a fair statement of the financial position and results of operations of the Company for the interim periods presented. All such adjustments are of a normal and recurring nature. There have been no significant changes in the accounting policies of the Company since December 31, 2014, the date of the most recent annual report.
Reclassifications	Reclassifications Certain items in prior financial statements have been reclassified to conform to the current presentation. Such reclassifications had no effect on previously reported cash flows, stockholders’ equity or comprehensive income.
Use of Estimates in the Preparation of Financial Statements	Use of Estimates in the Preparation of Financial Statements The preparation of financial statements in conformity with accounting principles generally accepted in the United States inherently involves the use of estimates and assumptions that affect the amounts reported in the financial statements and the related disclosures. These estimates relate principally to the determination of the allowance for loan losses, income taxes, the fair value of financial instruments and the valuation of intangibles. Such estimates and assumptions may change over time and actual amounts realized may differ from those reported.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In February 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2015-02, “Consolidation (Topic 810) – Amendments to the Consolidation Analysis.” ASU 2015-02 implements changes to both the variable interest consolidation model and the voting interest consolidation model. ASU 2015-02 (i) eliminates certain criteria that must be met when determining when fees paid to a decision maker or service provider do not represent a variable interest, (ii) amends the criteria for determining whether a limited partnership is a variable interest entity and (iii) eliminates the presumption that a general partner controls a limited partnership in the voting model. The amendments are effective for annual periods, and interim reporting periods within those annual periods, beginning after December 15, 2015. Adoption of ASU 2015-02 is not expected to have a significant effect on the Company’s financial statements. In August 2014, the FASB issued ASU No. 2014-15, “Presentation of Financial Statements – Going Concern (Topic 205-40).” ASU 2014-15 provides guidance on management’s responsibility in evaluating whether there is substantial doubt about the Company’s ability to continue as a going concern and related footnote disclosures. For each reporting period, management will be required to evaluate whether there are conditions or events that raise substantial doubt about the Company’s ability to continue as a going concern within one year from the date the financial statements are issued. The amendments are effective for annual periods, and interim reporting periods within those annual periods, beginning after December 15, 2016. Early adoption is permitted. Adoption of ASU 2014-15 is not expected to have a significant effect on the Company’s financial statements. In January 2014, the FASB issued Accounting Standards Update ASU No. 2014-04, “Receivables: Reclassification of Residential Real Estate Collateralized Consumer Mortgage Loans upon Foreclosure (Topic 310-40).” ASU 2014-04 clarifies that an in-substance repossession or foreclosure occurs upon either the creditor obtaining legal title to the residential real estate property or the borrower conveying all interest in the residential real estate property to the creditor to satisfy that loan through completion of a deed in lieu of foreclosure or through a similar legal agreement. The amendments were effective for annual periods, and interim reporting periods within those annual periods, beginning after December 15, 2014. Adoption of ASU 2014-04 did not have a significant effect on the Company’s financial statements. In January 2014, the FASB issued ASU No. 2014-01, “Accounting for Investments in Affordable Housing Projects (Topic 323).” ASU 2014-01 revises the necessary criteria that need to be met in order for an entity to account for investments in affordable housing projects net of the provision for income taxes. It also changes the method of recognition from an effective amortization approach to a proportional amortization approach. Additional disclosures were also set forth in this update. The amendments were effective for annual periods, and interim reporting periods within those annual periods, beginning after December 15, 2014. The amendments were required to be applied retrospectively to all periods presented. Early adoption was permitted and adoption of the standard was optional. Adoption of ASU 2014-01 did not have a material impact on the Company's financial statements.