BancFirst (BANF) 10-Q 9 May 14 2014 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2014	Apr. 30, 2014
Document And Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	31-Mar-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'
Trading Symbol	'BANF	'
Entity Registrant Name	'BANCFIRST CORP /OK/	'
Entity Central Index Key	'0000760498	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	15,371,478

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
In Thousands, unless otherwise specified
ASSETS	'	'	'
Cash and due from banks	$225,547	$196,547	$130,316
Interest-bearing deposits with banks	1,737,559	1,660,988	1,585,736
Federal funds sold	3,000	'	'
Securities (fair value: $587,100, $527,735, and $565,708, respectively)	587,018	527,627	565,490
Loans:	'	'	'
Total loans (net of unearned interest)	3,542,270	3,387,146	3,219,967
Allowance for loan losses	-39,924	-39,034	-38,664
Loans, net	3,502,346	3,348,112	3,181,303
Premises and equipment, net	121,354	117,862	116,729
Other real estate owned	7,328	8,149	9,098
Intangible assets, net	11,549	10,273	11,595
Goodwill	45,118	44,545	44,545
Accrued interest receivable and other assets	134,222	124,871	129,114
Total assets	6,375,041	6,038,974	5,773,926
Deposits:	'	'	'
Noninterest-bearing	2,133,583	2,085,753	1,934,427
Interest-bearing	3,604,267	3,333,766	3,240,085
Total deposits	5,737,850	5,419,519	5,174,512
Short-term borrowings	8,603	4,590	4,891
Long-term borrowings	2,000	6,938	11,040
Accrued interest payable and other liabilities	31,672	24,126	28,972
Junior subordinated debentures	26,804	26,804	26,804
Total liabilities	5,806,929	5,481,977	5,246,219
Commitments and contingent liabilities	'	'	'
Stockholders' equity:	'	'	'
Common stock, $1.00 par, 20,000,000 shares authorized; shares issued and outstanding: 15,363,728, 15,333,622 and 15,228,277, respectively	15,364	15,334	15,228
Capital surplus	89,951	88,803	82,956
Retained earnings	458,857	448,953	423,637
Accumulated other comprehensive income, net of income tax of $2,486, $2,103 and $3,169, respectively	3,940	3,907	5,886
Total stockholders' equity	568,112	556,997	527,707
Total liabilities and stockholders' equity	6,375,041	6,038,974	5,773,926
Senior preferred stock [Member]	'	'	'
Stockholders' equity:	'	'	'
preferred stock, value	'	'	'
Cumulative preferred stock [Member]	'	'	'
Stockholders' equity:	'	'	'
preferred stock, value	'	'	'

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
In Thousands, except Share data, unless otherwise specified
Securities, fair value	$587,100	$527,735	$565,708
Common stock, par value	$1	$1	$1
Common stock, shares authorized	20,000,000	20,000,000	20,000,000
Common stock, shares issued	15,363,728	15,333,622	15,228,277
Common stock, shares outstanding	15,363,728	15,333,622	15,228,277
Accumulated other comprehensive income, tax	$2,486	$2,103	$3,169
Senior preferred stock [Member]	'	'	'
Preferred stock, par value	$1	$1	$1
Preferred stock, shares authorized	10,000,000	10,000,000	10,000,000
Preferred stock, shares issued	0	0	0
Cumulative preferred stock [Member]	'	'	'
Preferred stock, par value	$5	$5	$5
Preferred stock, shares authorized	900,000	900,000	900,000
Preferred stock, shares issued	0	0	0

CONSOLIDATED_STATEMENTS_OF_COM

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
INTEREST INCOME	'	'
Loans, including fees	$42,649	$41,174
Securities:	'	'
Taxable	1,305	1,353
Tax-exempt	280	346
Federal funds sold	5	1
Interest-bearing deposits with banks	1,090	977
Total interest income	45,329	43,851
INTEREST EXPENSE	'	'
Deposits	2,789	3,040
Short-term borrowings	2	2
Long-term borrowings	18	62
Junior subordinated debentures	491	491
Total interest expense	3,300	3,595
Net interest income	42,029	40,256
Provision for loan losses	1,218	300
Net interest income after provision for loan losses	40,811	39,956
NONINTEREST INCOME	'	'
Trust revenue	2,151	1,906
Service charges on deposits	13,458	12,336
Securities transactions	450	122
Income from sales of loans	351	688
Insurance commissions	3,966	4,045
Cash management	1,585	1,423
Gain on sale of other assets	5	217
Other	1,596	1,798
Total noninterest income	23,562	22,535
NONINTEREST EXPENSE	'	'
Salaries and employee benefits	25,938	25,209
Occupancy and fixed assets expense, net	2,789	2,580
Depreciation	2,349	2,308
Amortization of intangible assets	408	443
Data processing services	1,170	1,185
Net expense from other real estate owned	550	122
Marketing and business promotion	1,716	1,507
Deposit insurance	773	743
Other	8,143	7,847
Total noninterest expense	43,836	41,944
Income before taxes	20,537	20,547
Income tax expense	5,880	7,175
Net income	14,657	13,372
NET INCOME PER COMMON SHARE	'	'
Basic	$0.96	$0.88
Diluted	$0.94	$0.86
OTHER COMPREHENSIVE INCOME	'	'
Unrealized gains (losses) on securities, net of tax of $(403) and $226, respectively	65	-421
Reclassification adjustment for gains included in net income, net of tax of $20 and $5, respectively	-32	-10
Other comprehensive gain (loss), net of tax of $(383) and $231, respectively	33	-431
Comprehensive income	$14,690	$12,941

CONSOLIDATED_STATEMENTS_OF_COM1

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (Parenthetical) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Income Statement [Abstract]	'	'
Unrealized gains (losses) on securities, net of tax	($403)	$226
Reclassification adjustment for gains, tax	20	5
Other comprehensive gain (loss), tax	($383)	$231

CONSOLIDATED_STATEMENTS_OF_STO

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) (USD $)	Total	COMMON STOCK [Member]	CAPITAL SURPLUS [Member]	RETAINED EARNINGS [Member]	ACCUMULATED OTHER COMPREHENSIVE INCOME [Member]
In Thousands
Balance at beginning of period at Dec. 31, 2012	'	$15,242	$82,401	$415,607	$6,317
Shares issued	'	9	158	'	'
Net income	13,372	'	'	13,372	'
Net change	-431	'	'	'	-431
Tax effect of stock options	'	'	23	'	'
Dividends on common stock	'	'	'	-4,422	'
Stock-based compensation arrangements	'	'	374	'	'
Shares acquired and canceled	'	-23	'	-920	'
Balance at end of period at Mar. 31, 2013	527,707	15,228	82,956	423,637	5,886
Balance at beginning of period at Dec. 31, 2013	556,997	15,334	88,803	448,953	3,907
Shares issued	'	30	878	'	'
Net income	14,657	'	'	14,657	'
Net change	33	'	'	'	33
Tax effect of stock options	'	'	-77	'	'
Dividends on common stock	'	'	'	-4,753	'
Stock-based compensation arrangements	'	'	347	'	'
Shares acquired and canceled	'	'	'	'	'
Balance at end of period at Mar. 31, 2014	$568,112	$15,364	$89,951	$458,857	$3,940

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOW (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
CASH FLOWS FROM OPERATING ACTIVITIES	'	'
Net income	$14,657	$13,372
Adjustments to reconcile to net cash provided by operating activities:	'	'
Provision for loan losses	1,218	300
Depreciation and amortization	2,757	2,751
Net amortization of securities premiums and discounts	276	417
Realized securities gains	-450	-122
Gain on sales of loans	-351	-688
Cash receipts from the sale of loans originated for sale	30,779	54,540
Cash disbursements for loans originated for sale	-29,189	-50,479
Deferred income tax provision	-1,934	-96
Gain on other assets	-62	-99
Decrease (increase) in interest receivable	133	-318
Decrease in interest payable	-200	-158
Amortization of stock-based compensation arrangements	347	374
Other, net	2,205	3,819
Net cash provided by operating activities	20,186	23,613
INVESTING ACTIVITIES	'	'
Net decrease in federal funds sold	1,619	700
Net cash and due from banks received from acquisitions	174,645	'
Purchases of held for investment securities	'	'
Purchases of available for sale securities	-99,914	-20,565
Proceeds from maturities, calls and paydowns of held for investment securities	718	315
Proceeds from maturities, calls and paydowns of available for sale securities	44,920	15,317
Proceeds from sales of available for sale securities	498	1,027
Purchases of loans	-14,126	-26,597
Proceeds from sales of loans	5,667	27,426
Net other (increase) decrease in loans	-37,970	17,252
Purchases of premises, equipment and computer software	-3,154	-3,683
Proceeds from the sale of other assets	812	988
Net cash provided by investing activities	73,715	12,180
FINANCING ACTIVITIES	'	'
Net increase (decrease) in demand, transaction and savings deposits	80,601	-239,034
Net decrease in time deposits	-64,084	-27,284
Net increase in short-term borrowings	4,013	320
(Paydown) issuance of long-term borrowings	-4,938	1,862
Issuance of common stock	831	190
Common stock acquired	'	-943
Cash dividends paid	-4,753	'
Net cash provided by (used in) financing activities	11,670	-264,889
Net increase (decrease) in cash, due from banks and interest-bearing deposits	105,571	-229,096
Cash, due from banks and interest-bearing deposits at the beginning of the period	1,857,535	1,945,148
Cash, due from banks and interest-bearing deposits at the end of the period	1,963,106	1,716,052
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:	'	'
Cash paid during the period for interest	2,991	3,753
Cash paid during the period for income taxes	850	'
Noncash investing and financing activities:	'	'
Unpaid common stock dividends declared	$4,744	$4,422

DESCRIPTION_OF_BUSINESS_AND_SU

DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	'
	-1	DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
	The accounting and reporting policies of BancFirst Corporation and its subsidiaries (the “Company”) conform to accounting principles generally accepted in the United State of America (U.S. GAAP) and general practice within the banking industry. A summary of significant accounting policies can be found in Note (1) to the Company’s Annual Report on Form 10-K for the year ended December 31, 2013.
	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., BancFirst Agency, Inc. and BancFirst Community Development Corporation. 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, 2013, should be referred to in connection with these unaudited interim consolidated financial statements.
	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, 2013, the date of the most recent annual report.
	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.
	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.
	Recent Accounting Pronouncements
	In January 2014, the Financial Accounting Standards Board (“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 are effective for annual periods, and interim reporting periods within those annual periods, beginning after December 15, 2014. The amendments may be adopted using either a modified retrospective transition method or a prospective transition method. Early adoption is permitted. Adoption of ASU 2014-04 is not expected to 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 are effective for annual periods, and interim reporting periods within those annual periods, beginning after December 15, 2014. The amendments are required to be applied retrospectively to all periods presented. Early adoption is permitted. Adoption of ASU 2014-01 is not expected to have a significant effect on the Company’s financial statements.
	In February 2013, the FASB issued ASU No. 2013-02, “Comprehensive Income (Topic 220).” ASU 2013-02 requires an entity to provide information about the amounts reclassified out of accumulated other comprehensive income by component. An entity is required to present, either on the face of the statement where net income is presented or in the notes, significant amounts reclassified out of accumulated other comprehensive income by the respective line items of net income but only if the amount reclassified is required under U.S. GAAP to be reclassified to net income in its entirety in the same reporting period. The new standard was effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2012. Adoption of ASU 2013-02 did not have a significant effect on the Company’s financial statements.

RECENT_DEVELOPMENTS_INCLUDING_

RECENT DEVELOPMENTS, INCLUDING MERGERS AND ACQUISITIONS	3 Months Ended
	Mar. 31, 2014
Text Block [Abstract]	'
RECENT DEVELOPMENTS, INCLUDING MERGERS AND ACQUISITIONS	'
	-2	RECENT DEVELOPMENTS, INCLUDING MERGERS AND ACQUISITIONS
	On January 24, 2014, BancFirst, a wholly-owned subsidiary of BancFirst Corporation, assumed all of the deposits and purchased certain assets of The Bank of Union, El Reno, Oklahoma (“The Bank of Union”). The Bank of Union was closed on that day by the Oklahoma State Banking Department.
	At the time of the closing, The Bank of Union had total deposits of approximately $302 million that were assumed by BancFirst. BancFirst initially purchased approximately $121 million of loans, the majority of which were classified as performing, $4.8 million of securities, and only $10,000 of other real estate. Its bid included a discount for the loans purchased. BancFirst had bid on, but was generally not awarded, loans that were classified as nonperforming. The acquisition did not have a material effect on the Company’s consolidated financial statements.
	At March 31, 2014, the acquired branch had approximately $98.8 million of loans, the majority of which are classified as performing, and deposits of approximately $231.0 million.

SECURITIES

SECURITIES	3 Months Ended
	Mar. 31, 2014
Investments Debt And Equity Securities [Abstract]	'
SECURITIES	'
	-3	SECURITIES
	The following table summarizes securities held for investment and securities available for sale:
			March 31, 2014
			(Dollars in thousands)
	Held for investment, at cost (fair value: $11,351)		$	11,269
	Available for sale, at fair value			575,749
	Total		$	587,018
	The following table summarizes the amortized cost and estimated fair values of securities held for investment:
			March 31, 2014
			Amortized		Gross		Gross			Estimated
			Cost		Unrealized		Unrealized			Fair
					Gains		Losses			Value
			(Dollars in thousands)
	Mortgage backed securities (1)		$	575	$	41	$	—		$	616
	States and political subdivisions			10,694		48		(7	)		10,735
	Total		$	11,269	$	89	$	(7	)	$	11,351
	The following table summarizes the amortized cost and estimated fair values of securities available for sale:
			March 31, 2014
			Amortized		Gross		Gross			Estimated
			Cost		Unrealized		Unrealized			Fair
					Gains		Losses			Value
			(Dollars in thousands)
	U.S. treasury and other federal agencies		$	474,579	$	1,452	$	(498	)	$	475,533
	Mortgage backed securities (1)			29,228		637		(1	)		29,864
	States and political subdivisions			53,456		1,583		(68	)		54,971
	Other securities (2)			12,060		3,462		(141	)		15,381
	Total		$	569,323	$	7,134	$	(708	)	$	575,749
	-1	Primarily consists of FHLMC, FNMA, GNMA and mortgage backed securities through U.S. agencies.
	-2	Primarily consists of equity securities.
	The maturities of securities held for investment and available for sale are summarized in the following table using contractual maturities. Actual maturities may differ from contractual maturities due to obligations that are called or prepaid. For purposes of the maturity table, mortgage-backed securities, which are not due at a single maturity date, have been presented at their contractual maturity.
			March 31, 2014
			Amortized		Estimated
			Cost		Fair
					Value
			(Dollars in thousands)
	Held for Investment
	Contractual maturity of debt securities:
	Within one year		$	3,190	$	3,193
	After one year but within five years			7,240		7,274
	After five years but within ten years			639		662
	After ten years			200		222
	Total		$	11,269	$	11,351
	Available for Sale
	Contractual maturity of debt securities:
	Within one year		$	172,145	$	172,418
	After one year but within five years			267,092		267,938
	After five years but within ten years			27,354		28,056
	After ten years			94,085		95,439
	Total debt securities			560,676		563,851
	Equity securities			8,647		11,898
	Total		$	569,323	$	575,749
	The following table is a summary of the Company’s book value of securities that were pledged as collateral for public funds on deposit, repurchase agreements and for other purposes as required or permitted by law:
			March 31, 2014
			(Dollars in thousands)
	Book value of pledged securities		$	434,972

LOANS_AND_ALLOWANCE_FOR_LOAN_L

LOANS AND ALLOWANCE FOR LOAN LOSSES	3 Months Ended
	Mar. 31, 2014
Receivables [Abstract]	'
LOANS AND ALLOWANCE FOR LOAN LOSSES	'
	-4	LOANS AND ALLOWANCE FOR LOAN LOSSES
	The following is a schedule of loans outstanding by category:
			March 31, 2014						December 31, 2013						March 31, 2013
			Amount			Percent			Amount			Percent			Amount			Percent
			(Dollars in thousands)
	Commercial and industrial		$	676,084			19.09	%	$	605,672			17.88	%	$	518,438			16.1	%
	Oil & gas production & equipment			99,382			2.8			96,907			2.86			154,392			4.79
	Agriculture			109,570			3.09			111,323			3.29			96,094			2.98
	State and political subdivisions:
	Taxable			9,824			0.28			10,217			0.3			9,272			0.29
	Tax-exempt			11,219			0.32			11,073			0.33			13,034			0.41
	Real estate:
	Construction			299,238			8.45			284,808			8.41			231,770			7.2
	Farmland			141,059			3.98			132,512			3.91			124,347			3.86
	One to four family residences			723,358			20.42			703,903			20.78			680,129			21.12
	Multifamily residential properties			60,785			1.72			60,080			1.77			47,506			1.48
	Commercial			1,134,384			32.02			1,097,484			32.4			1,084,864			33.69
	Consumer			251,651			7.1			250,588			7.4			240,600			7.47
	Other (not classified above)			25,716			0.73			22,579			0.67			19,521			0.61
	Total loans		$	3,542,270			100	%	$	3,387,146			100	%	$	3,219,967			100	%
	Loans held for sale (included above)		$	5,231					$	6,469					$	7,211
	The Company’s loans are mostly to customers within Oklahoma and over 60% of the loans are secured by real estate. Credit risk on loans is managed through limits on amounts loaned to individual borrowers, underwriting standards and loan monitoring procedures. The amounts and types of collateral obtained, if any, to secure loans are based upon the Company’s underwriting standards and management’s credit evaluation. Collateral varies, but may include real estate, equipment, accounts receivable, inventory, livestock and securities. The Company’s interest in collateral is secured through filing mortgages and liens, and in some cases, by possession of the collateral.
	Accounting policies related to appraisals, nonaccruals and charge-offs are disclosed in Note (1) to the Company’s Annual Report on Form 10-K for the year ended December 31, 2013.
	Nonperforming and Restructured Assets
	The following is a summary of nonperforming and restructured assets:
			March 31,			December 31,			March 31,
			2014			2013			2013
			(Dollars in thousands)
	Past due 90 days or more and still accruing		$	910		$	1,179		$	542
	Nonaccrual			17,753			14,390			20,933
	Restructured			17,468			17,624			17,792
	Total nonperforming and restructured loans			36,131			33,193			39,267
	Other real estate owned and repossessed assets			7,590			8,386			9,424
	Total nonperforming and restructured assets		$	43,721		$	41,579		$	48,691
	Nonperforming and restructured loans to total loans			1.02	%		0.98	%		1.22	%
	Nonperforming and restructured assets to total assets			0.69	%		0.69	%		0.84	%
	Nonaccrual loans, accruing loans past due 90 days or more, and restructured loans are shown in the table above. Had nonaccrual loans performed in accordance with their original contractual terms, the Company would have recognized additional interest income of approximately $227,000 for the three months ended March 31, 2014 and approximately $301,000 for the three months ended March 31, 2013.
	Restructured loans consisted primarily of one relationship restructured to defer principal payments. The relationship was evaluated by management and determined to be well collateralized. Additionally, none of the concessions granted involved a principal reduction or a change from the current market rate of interest. The collateral value is monitored periodically to evaluate possible impairment. The Company charges interest on principal balances outstanding during deferral periods. As a result, the current and future financial effects of the recorded balance of loans considered to be restructured were not considered to be material.
	Loans are segregated into classes based upon the nature of the collateral and the borrower. These classes are used to estimate the allowance for loan losses.
	The following table is a summary of amounts included in nonaccrual loans, segregated by class of loans. Residential real estate refers to one-to-four family real estate.
			March 31,			March 31,
			2014			2013
			(Dollars in thousands)
	Non-residential real estate owner occupied		$	448		$	382
	Non-residential real estate other			5,779			9,284
	Residential real estate permanent mortgage			689			619
	Residential real estate all other			958			3,716
	Non-consumer non-real estate			1,287			1,449
	Consumer non-real estate			165			187
	Other loans			1,198			3,052
	Acquired loans			7,229			2,244
	Total		$	17,753		$	20,933
	The following table presents an age analysis of past due loans, segregated by class of loans:
			Age Analysis of Past Due Loans
			30-89			90 Days			Total			Current			Total Loans			Accruing
			Days			and			Past Due			Loans						Loans
			Past Due			Greater			Loans									90 Days
																		or More
																		Past Due
			(Dollars in thousands)
	As of March 31, 2014
	Non-residential real estate owner occupied		$	518		$	298		$	816		$	457,978		$	458,794		$	96
	Non-residential real estate other			4,978			935			5,913			873,592			879,505			—
Residential real estate permanent mortgage			1,867			458			2,325			270,879			273,204			76
Residential real estate all other			1,274			543			1,817			565,930			567,747			86
Non-consumer non-real estate			2,749			929			3,678			824,361			828,039			18
Consumer non-real estate			2,151			260			2,411			223,551			225,962			218
Other loans			2,080			337			2,417			145,794			148,211			—
Acquired loans			3,053			4,608			7,661			153,147			160,808			416
Total		$	18,670		$	8,368		$	27,038		$	3,515,232		$	3,542,270		$	910
As of March 31, 2013
Non-residential real estate owner occupied		$	1,230		$	112		$	1,342		$	452,461		$	453,803		$	18
Non-residential real estate other			2,063			1,833			3,896			786,343			790,239			—
Residential real estate permanent mortgage			2,351			460			2,811			245,945			248,756			163
Residential real estate all other			2,087			408			2,495			522,542			525,037			105
Non-consumer non-real estate			2,100			214			2,314			748,287			750,601			74
Consumer non-real estate			1,994			184			2,178			209,142			211,320			126
Other loans			2,152			1,406			3,558			140,468			144,026			—
Acquired loans			1,993			328			2,321			93,864			96,185			56
Total		$	15,970		$	4,945		$	20,915		$	3,199,052		$	3,219,967		$	542
Impaired Loans
Loans are considered impaired when, based on current information and events, it is probable the Company will be unable to collect the full amount of scheduled principal and interest payments in accordance with the original contractual terms of the loan agreement. If a loan is impaired, a specific valuation allowance may be allocated if necessary so that the loan is reported, net of allowance for loss, at the present value of future cash flows using the loan’s existing rate, or the fair value of collateral if repayment is expected solely from the collateral.
The following table presents impaired loans, segregated by class of loans. No material amount of interest income was recognized on impaired loans subsequent to their classification as impaired.
		Impaired Loans
		Unpaid			Recorded			Related			Average
		Principal			Investment			Allowance			Recorded
		Balance			with Allowance						Investment
		(Dollars in thousands)
As of March 31, 2014
Non-residential real estate owner occupied		$	688		$	601		$	29		$	642
Non-residential real estate other			24,355			22,680			1,734			22,915
Residential real estate permanent mortgage			1,068			836			88			918
Residential real estate all other			1,318			1,139			218			1,335
Non-consumer non-real estate			1,824			1,491			427			1,449
Consumer non-real estate			548			527			134			572
Other loans			1,215			1,198			207			1,278
Acquired loans			20,179			13,361			189			9,744
Total		$	51,195		$	41,833		$	3,026		$	38,853
As of March 31, 2013
Non-residential real estate owner occupied		$	580		$	517		$	19		$	732
Non-residential real estate other			27,369			25,900			2,166			26,082
Residential real estate permanent mortgage			1,448			1,226			61			1,007
Residential real estate all other			4,631			4,246			1,276			3,840
Non-consumer non-real estate			1,899			1,565			452			2,249
Consumer non-real estate			441			421			96			408
Other loans			3,736			3,094			267			2,648
Acquired loans			10,311			8,261			41			8,893
Total		$	50,415		$	45,230		$	4,378		$	45,859
Credit Risk Monitoring and Loan Grading
The Company considers various factors to monitor the credit risk in the loan portfolio including volume and severity of loan delinquencies, nonaccrual loans, internal grading of loans, historical loan loss experience, and economic conditions.
An internal risk grading system is used to indicate the credit risk of loans. The loan grades used by the Company are for internal risk identification purposes and do not directly correlate to regulatory classification categories or any financial reporting definitions.
The general characteristics of the risk grades are disclosed in Note (5) to the Company’s Annual Report on Form 10-K for the year ended December 31, 2013.
The following table presents internal loan grading by class of loans:
		Internal Loan Grading
		Grade
		1			2			3			4			5			Total
		(Dollars in thousands)
As of March 31, 2014
Non-residential real estate owner occupied		$	381,290		$	70,949		$	6,052		$	503		$	—		$	458,794
Non-residential real estate other			724,181			129,390			20,155			5,779			—			879,505
Residential real estate permanent mortgage			240,653			25,074			6,610			867			—			273,204
Residential real estate all other			474,152			86,033			6,495			1,067			—			567,747
Non-consumer non-real estate			673,757			147,625			5,350			1,307			—			828,039
Consumer non-real estate			212,492			11,388			1,655			427			—			225,962
Other loans			144,870			2,375			736			230			—			148,211
Acquired loans			92,581			48,073			12,091			7,917			146			160,808
Total		$	2,943,976		$	520,907		$	59,144		$	18,097		$	146		$	3,542,270
As of March 31, 2013
Non-residential real estate owner occupied		$	393,152		$	55,109		$	5,142		$	400		$	—		$	453,803
Non-residential real estate other			649,917			110,186			20,852			9,284			—			790,239
Residential real estate permanent mortgage			208,732			33,463			5,730			831			—			248,756
Residential real estate all other			461,620			51,181			8,410			3,826			—			525,037
Non-consumer non-real estate			647,162			97,110			4,800			1,529			—			750,601
Consumer non-real estate			198,107			10,912			1,923			374			4			211,320
Other loans			139,696			2,304			1,103			923			—			144,026
Acquired loans			74,939			14,936			4,009			2,301			—			96,185
Total		$	2,773,325		$	375,201		$	51,969		$	19,468		$	4		$	3,219,967
Allowance for Loan Losses Methodology
The allowance for loan losses (“ALL”) methodology is disclosed in Note (5) to the Company’s Annual Report on Form 10-K for the year ended December 31, 2013.
The following table details activity in the ALL by class of loans for the period presented. Allocation of a portion of the allowance to one category of loans does not preclude its availability to absorb losses in other catagories.
		ALL
		Balance at			Charge-			Recoveries			Net			Provisions			Balance
		beginning			offs						charge-			charged to			at end of
		of period									offs			operations			period
		(Dollars in thousands)
Three Months Ended March 31, 2014
Non-residential real estate owner occupied		$	4,827		$	(4	)	$	31		$	27		$	158		$	5,012
Non-residential real estate other			11,026			—			3			3			(344	)		10,685
Residential real estate permanent mortgage			2,825			(130	)		10			(120	)		532			3,237
Residential real estate all other			6,708			(49	)		4			(45	)		(178	)		6,485
Non-consumer non-real estate			8,977			(70	)		14			(56	)		782			9,703
Consumer non-real estate			2,556			(140	)		62			(78	)		95			2,573
Other loans			1,991			(64	)		17			(47	)		128			2,072
Acquired loans			124			(17	)		5			(12	)		45			157
Total		$	39,034		$	(474	)	$	146		$	(328	)	$	1,218		$	39,924
		ALL
		Balance at			Charge-			Recoveries			Net			Provisions			Balance
		beginning			offs						charge-			charged to			at end of
		of period									offs			operations			period
		(Dollars in thousands)
Three Months Ended March 31, 2013
Non-residential real estate owner occupied		$	5,104		$	—		$	15		$	15		$	(253	)	$	4,866
Non-residential real estate other			9,865			(18	)		4			(14	)		614			10,465
Residential real estate permanent mortgage			2,781			(56	)		11			(45	)		20			2,756
Residential real estate all other			7,034			(95	)		2			(93	)		224			7,165
Non-consumer non-real estate			9,385			(36	)		31			(5	)		(398	)		8,982
Consumer non-real estate			2,451			(140	)		76			(64	)		(3	)		2,384
Other loans			1,885			(139	)		—			(139	)		76			1,822
Acquired loans			220			(49	)		33			(16	)		20			224
Total		$	38,725		$	(533	)	$	172		$	(361	)	$	300		$	38,664
The following table details the amount of ALL by class of loans for the period presented, on the basis of the impairment methodology used by the Company.
		ALL
		March 31, 2014						March 31, 2013
		Individually			Collectively			Individually			Collectively
		evaluated for			evaluated for			evaluated for			evaluated for
		impairment			impairment			impairment			impairment
		(Dollars in thousands)
Non-residential real estate owner occupied		$	361		$	4,651		$	210		$	4,656
Non-residential real estate other			1,929			8,756			2,484			7,981
Residential real estate permanent mortgage			588			2,649			224			2,532
Residential real estate all other			733			5,752			1,899			5,266
Non-consumer non-real estate			1,133			8,570			1,211			7,771
Consumer non-real estate			389			2,184			290			2,094
Other loans			242			1,830			199			1,623
Acquired loans			—			157			—			224
Total		$	5,375		$	34,549		$	6,517		$	32,147
The following table details the loans outstanding by class of loans for the period presented, on the basis of the impairment methodology used by the Company.
		Loans
		March 31, 2014									March 31, 2013
		Individually			Collectively			Loans acquired			Individually			Collectively			Loans acquired
		evaluated for			evaluated for			with			evaluated for			evaluated for			with
		impairment			impairment			deteriorated			impairment			impairment			deteriorated
								credit quality									credit quality
		(Dollars in thousands)
Non-residential real estate owner occupied		$	6,555		$	452,239		$	—		$	5,542		$	448,261		$	—
Non-residential real estate other			25,934			853,571			—			30,136			760,103			—
Residential real estate permanent mortgage			7,477			265,727			—			6,561			242,195			—
Residential real estate all other			7,562			560,185			—			12,236			512,801			—
Non-consumer non-real estate			6,657			821,382			—			6,329			744,272			—
Consumer non-real estate			2,082			223,880			—			2,301			209,019			—
Other loans			308			147,903			—			246			143,780			—
Acquired loans			—			140,654			20,154			—			89,875			6,310
Total		$	56,575		$	3,465,541		$	20,154		$	63,351		$	3,150,306		$	6,310
Transfers from Loans
Transfers from loans to other real estate owned and repossessed assets are non-cash transactions, and are not included in the statements of cash flow.
Transfers from loans to other real estate owned and repossessed assets during the periods presented are summarized as follows:
		Three Months Ended
		March 31,
		2014			2013
		(Dollars in thousands)
Other real estate owned		$	66		$	436
Repossessed assets			327			209
Total		$	393		$	645

INTANGIBLE_ASSETS

INTANGIBLE ASSETS	3 Months Ended
	Mar. 31, 2014
Goodwill And Intangible Assets Disclosure [Abstract]	'
INTANGIBLE ASSETS	'
	-5	INTANGIBLE ASSETS
	The following is a summary of intangible assets:
			Gross		Accumulated			Net
			Carrying		Amortization			Carrying
			Amount					Amount
			(Dollars in thousands)
	As of March 31, 2014
	Core deposit intangibles		$	12,681	$	(4,938	)	$	7,743
	Customer relationship intangibles			5,699		(2,428	)		3,271
	Mortgage servicing intangibles			696		(161	)		535
	Total		$	19,076	$	(7,527	)	$	11,549
	The following is a summary of goodwill by business segment:
			Metropolitan		Community			Other		Executive,		Consolidated
			Banks		Banks			Financial		Operations
								Services		& Support
			(Dollars in thousands)
	As of March 31, 2014
	Balance at beginning of period		$	8,079	$	30,552		$	5,464	$	450	$	44,545
	Acquisitions			—		573			—		—		573
	Balance at end of period		$	8,079	$	31,125		$	5,464	$	450	$	45,118
	Additional information for intangible assets can be found in Note (7) to the Company’s Annual Report on Form 10-K for the year ended December 31, 2013.

STOCKBASED_COMPENSATION

STOCK-BASED COMPENSATION	3 Months Ended
	Mar. 31, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
STOCK-BASED COMPENSATION	'
	-6	STOCK-BASED COMPENSATION
	The Company adopted a nonqualified incentive stock option plan (the “BancFirst ISOP”) in May 1986. The Company amended the BancFirst ISOP to increase the number of shares to be issued under the plan to 3,000,000 shares in May 2013. At March 31, 2014, 145,860 shares were available for future grants. The BancFirst ISOP will terminate on December 31, 2014. The options vest and are exercisable beginning four years from the date of grant at the rate of 25% per year for four years. Options expire at the end of fifteen years from the date of grant. Options outstanding as of March 31, 2014 will become exercisable through the year 2020. The option price must be no less than 100% of the fair value of the stock relating to such option at the date of grant.
	In June 1999, the Company adopted the BancFirst Corporation Non-Employee Directors’ Stock Option Plan (the “BancFirst Directors’ Stock Option Plan”). Each non-employee director is granted an option for 10,000 shares. The Company amended the BancFirst Directors’ Stock Option Plan to increase the number of shares to be issued under the plan to 205,000 shares in May 2009. At March 31, 2014, 5,000 shares were available for future grants. The options vest and are exercisable beginning one year from the date of grant at the rate of 25% per year for four years, and expire at the end of fifteen years from the date of grant. Options outstanding as of March 31, 2014 will become exercisable through the year 2017. The option price must be no less than 100% of the fair value of the stock relating to such option at the date of grant.
	The Company currently uses newly issued shares for stock option exercises, but reserves the right to use shares purchased under the Company’s Stock Repurchase Program (the “SRP”) in the future.
	The following table is a summary of the activity under both the BancFirst ISOP and the BancFirst Directors’ Stock Option Plan:
			Options			Wgtd.		Wgtd. Avg.			Aggregate
						Avg.		Remaining			Intrinsic
						Exercise		Contractual			Value
						Price		Term
			(Dollars in thousands, except per share data)
	Three Months Ended March 31, 2014
	Outstanding at December 31, 2013			1,158,317		$	34.45
	Options granted			—			—
	Options exercised			(28,750	)		30.1
	Options canceled, forfeited or expired			—			—
	Outstanding at March 31, 2014			1,129,567			34.56		8.63	Yrs	$	24,931
	Exercisable at March 31, 2014			538,667			28.01		6.19	Yrs	$	15,415
	The following table has additional information regarding options granted and options exercised under both the BancFirst ISOP and the BancFirst Directors’ Stock Option Plan:
			Three Months Ended
			March 31,
			2014			2013
			(Dollars in thousands)
	Weighted average grant-date fair value per share of options granted		$	—		$	—
	Total intrinsic value of options exercised			745			206
	Cash received from options exercised			865			142
	Tax benefit realized from options exercised			288			80
	The fair value of each option grant is estimated on the date of grant using the Black-Scholes option-pricing model and is based on certain assumptions including risk-free rate of return, dividend yield, stock price volatility, and the expected term. The fair value of each option is expensed over its vesting period.
	The following table is a summary of the Company’s recorded stock-based compensation expense:
			Three Months Ended
			March 31,
			2014			2013
			(Dollars in thousands)
	Stock-based compensation expense		$	347		$	374
	Tax benefit			134			145
	Stock-based compensation expense, net of tax		$	213		$	229
	The Company will continue to amortize the remaining fair value of stock options over the remaining vesting period of approximately seven years. The following table shows the remaining fair value of stock options:
			March 31, 2014
			(Dollars in thousands)
	Fair value of stock options		$	4,778

STOCKHOLDERS_EQUITY

STOCKHOLDERS' EQUITY	3 Months Ended
	Mar. 31, 2014
Equity [Abstract]	'
STOCKHOLDERS' EQUITY	'
	-7	STOCKHOLDERS’ EQUITY
	In November 1999, the Company adopted a Stock Repurchase Program (the “SRP”). The SRP may be used as a means to increase earnings per share and return on equity, to purchase treasury stock for the exercise of stock options or for distributions under the Deferred Stock Compensation Plan, to provide liquidity for optionees to dispose of stock from exercises of their stock options, and to provide liquidity for stockholders wishing to sell their stock. All shares repurchased under the SRP have been retired and not held as treasury stock. The timing, price and amount of stock repurchases under the SRP may be determined by management and approved by the Company’s Executive Committee.
	The following table is a summary of the shares under the program:
			Three Months Ended
			March 31,
			2014		2013
	Number of shares repurchased			—		23,050
	Average price of shares repurchased			—	$	40.92
	Shares remaining to be repurchased			194,723		211,914
	The Company and BancFirst are subject to risk-based capital guidelines issued by the Board of Governors of the Federal Reserve System and the FDIC. These guidelines are used to evaluate capital adequacy and involve both quantitative and qualitative evaluations of the Company’s and BancFirst’s assets, liabilities, and certain off-balance-sheet items calculated under regulatory practices. Failure to meet the minimum capital requirements can initiate certain mandatory or discretionary actions by the regulatory agencies that could have a direct material effect on the Company’s financial statements. Management believes that as of March 31, 2014, the Company and BancFirst met all capital adequacy requirements to which they are subject. The actual and required capital amounts and ratios are shown in the following table:
			Actual					Required					To Be Well
								For Capital					Capitalized Under
								Adequacy					Prompt Corrective
								Purposes					Action Provisions
			Amount		Ratio			Amount		Ratio			Amount		Ratio
			(Dollars in thousands)
	As of March 31, 2014:
	Total Capital
	(to Risk Weighted Assets)-
	BancFirst Corporation.		$	573,963		14.52	%	$	316,297		8	%		N/A		N/A
	BancFirst			537,600		13.62	%		315,685		8	%	$	394,606		10	%
	Tier 1 Capital
	(to Risk Weighted Assets)-
	BancFirst Corporation			534,039		13.51	%		158,148		4	%		N/A		N/A
	BancFirst			497,676		12.61	%		157,842		4	%		236,763		6	%
	Tier 1 Capital
	(to Total Assets)-
	BancFirst Corporation			534,039		8.45	%		191,252		3	%		N/A		N/A
	BancFirst			497,676		7.89	%		190,650		3	%		317,750		5	%
	As of March 31, 2014, BancFirst was considered to be “well capitalized” and there are no conditions or events since the most recent notification of BancFirst’s capital category that management believes would materially change its category under capital requirements existing as of the report date. To be well capitalized under Federal bank regulatory agency definitions, a depository institution must have a Tier 1 Capital (to Risk Weighted Assets) of at least 6%, a Total Capital (to Risk Weighted Assets) of at least 10%, and a Tier 1 Capital (to Total Assets) of at least 5%. The Company’s trust preferred securities have continued to be included in Tier 1 capital as the Company’s total assets do not exceed $10 billion.
	Basel III Capital Rules
	In July 2013, the three Federal bank regulatory agencies jointly published interim final rules (the “Basel III Capital Rules”) establishing a new comprehensive capital framework for U.S. banking organizations. The rules implement the Basel Committee’s December 2010 framework known as “Basel III” for strengthening international capital standards as well as certain provisions of the Dodd-Frank Act. These Rules substantially revise the risk-based capital requirements applicable to bank holding companies and depository institutions, compared to the current U.S. risk-based capital rules. The Basel III Capital Rules define the components of capital and address other issues affecting the numerator in banking institutions’ regulatory capital ratios. These Rules also address risk weights and other issues affecting the denominator in banking institutions’ regulatory capital ratios and replace the existing risk-weighting approach with a more risk-sensitive approach. The Basel III Capital Rules also implement the requirements of Section 939A of the Dodd-Frank Act to remove references to credit ratings from the federal banking agencies’ rules. The Basel III Capital Rules are effective for the Company and BancFirst on January 1, 2015 (subject to a 4-year phase-in period).
	The Basel III Capital Rules, among other things, (i) introduce a new capital measure called “Common Equity Tier 1” (“CET1”), (ii) specify that Tier 1 capital consist of CET1 and “Additional Tier 1 capital” instruments meeting specified requirements, (iii) define CET1 narrowly by requiring that most deductions/adjustments to regulatory capital measures be made to CET1 and not to the other components of capital, and (iv) expand the scope of the deductions/adjustments as compared to existing regulations.
	Under the Basel III Capital Rules, the initial minimum capital ratios as of January 1, 2015 will be as follows:
	4.5% CET1 to risk-weighted assets.
	6.0% Tier 1 capital to risk-weighted assets.
	8.0% Total capital to risk-weighted assets.
	4.0% Minimum leverage ratio
	Implementation of the deductions and other adjustments to CET1 will begin on January 1, 2015 and will be phased-in over a 4-year period (beginning at 40% on January 1, 2015 and an additional 20% per year thereafter). Under the new rule, in order to avoid limitations on capital distributions, including dividend payments and certain discretionary bonus payments to executive officers, a banking organization must hold a capital conservation buffer composed of CET1 capital above its minimum risk-based capital requirements. The implementation of the capital conservation buffer will begin on January 1, 2016 at the 0.625% level and be phased in over a four-year period (increasing by that amount on each subsequent January 1, until it reaches 2.5% on January 1, 2019).
	Management believes that, as of March 31, 2014, the Company and BancFirst would meet all capital adequacy requirements under the Basel III Capital Rules on a fully phased-in basis as if such requirements were currently in effect.

NET_INCOME_PER_COMMON_SHARE

NET INCOME PER COMMON SHARE	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
NET INCOME PER COMMON SHARE	'
	-8	NET INCOME PER COMMON SHARE
	Basic and diluted net income per common share are calculated as follows:
			Income		Shares		Per
			(Numerator)		(Denominator)		Share
							Amount
			(Dollars in thousands, except per share data)
	Three Months Ended March 31, 2014
	Basic
	Income available to common stockholders		$	14,657		15,342,486	$	0.96
	Effect of stock options			—		318,434
	Diluted
	Income available to common stockholders plus assumed exercises of stock options		$	14,657		15,660,920	$	0.94
	Three Months Ended March 31, 2013
	Basic
	Income available to common stockholders		$	13,372		15,238,701	$	0.88
	Effect of stock options			—		243,816
	Diluted
	Income available to common stockholders plus assumed exercises of stock options		$	13,372		15,482,517	$	0.86
	The following table shows the number and average exercise price of options that were excluded from the computation of diluted net income per common share for each period because the options’ exercise prices were greater than the average market price of the common shares:
			Shares		Average
					Exercise Price
	Three Months Ended March 31, 2014			65,000	$	54.01
	Three Months Ended March 31, 2013			534,000		39.44

FAIR_VALUE_MEASUREMENTS

FAIR VALUE MEASUREMENTS	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
FAIR VALUE MEASUREMENTS	'
	-9	FAIR VALUE MEASUREMENTS
	Accounting standards define fair value as the price that would be received to sell an asset or the price paid to transfer a liability in the principal or most advantageous market available to the entity in an orderly transaction between market participants on the measurement date.
	FASB ASC Topic 820 establishes a fair value hierarchy for valuation inputs that gives the highest priority to quoted prices in active markets for identical assets or liabilities and the lowest priority to unobservable inputs. The fair value hierarchy is as follows:
	Ÿ    Level 1	Inputs to the valuation methodology are quoted prices (unadjusted) for identical assets or liabilities in active markets.
	Ÿ    Level 2	Inputs to the valuation methodology include quoted prices for similar assets and liabilities in active markets, and inputs that are observable for the asset and liability, either directly or indirectly, for substantially the full term of the financial instrument.
	Ÿ    Level 3	Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Level 3 assets and liabilities include financial instruments whose values are determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation. This category includes certain impaired loans, foreclosed assets, other real estate, goodwill and other intangible assets.
	Financial Assets and Financial Liabilities Measured at Fair Value on a Recurring Basis
	A description of the valuation methodologies and key inputs used to measure financial assets and financial liabilities at fair value on a recurring basis, as well as the general classification of such instruments pursuant to the valuation hierarchy, is set forth below. These valuation methodologies were applied to the following categories of the Company’s financial assets and financial liabilities.
	Securities Available for Sale
	Securities classified as available for sale are reported at fair value. U.S. Treasuries are valued using Level 1 inputs. Other securities available for sale including U.S. federal agencies, mortgage backed securities, and state and political subdivisions are valued using prices from an independent pricing service utilizing Level 2 data. The fair value measurements consider observable data that may include dealer quotes, market spreads, cash flows, the U.S. Treasury yield curve, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the bond’s terms and conditions, among other things. The Company also invests in equity securities classified as available for sale for which observable information is not readily available. These securities are reported at fair value utilizing Level 3 inputs. For these securities, management determines the fair value based on the income approach or information provided by outside consultants or lead investors.
	The Company reviews the prices for Level 1 and Level 2 securities supplied by the independent pricing service for reasonableness and to ensure such prices are aligned with traditional pricing matrices. In general, the Company does not purchase investment portfolio securities that are esoteric or that have complicated structures. The Company’s entire portfolio consists of traditional investments including U.S. Treasury obligations, federal agency mortgage pass-through securities, general obligation municipal bonds and a small amount of municipal revenue bonds. Pricing for such instruments is fairly generic and is easily obtained. For in-state bond issues that have relatively low issue sizes and liquidity, the Company utilizes the same parameters adjusted for the specific issue. From time to time, the Company will validate, on a sample basis, prices supplied by the independent pricing service by comparison to prices obtained from third party sources.
	Derivatives
	Derivatives are reported at fair value utilizing Level 2 inputs. The Company obtains dealer and market quotations to value its oil and gas swaps and options. The Company utilizes dealer quotes and observable market data inputs to substantiate internal valuation models.
	Loans Held For Sale
	The Company originates mortgage loans to be sold. At the time of origination, the acquiring bank has already been determined and the terms of the loan, including interest rate, have already been set by the acquiring bank, allowing the Company to originate the loan at fair value. Mortgage loans are generally sold within 30 days of origination. Loans held for sale are valued using Level 2 inputs. Gains or losses recognized upon the sale of the loans are determined on a specific identification basis.
	Mortgage Servicing Intangibles
	The Company acquired Mortgage Servicing Intangibles with the acquisition of 1st Bank Oklahoma on July 12, 2011. Mortgage Servicing Intangibles are amortized based on current prepayment assumptions and are adjusted to fair value quarterly, if impaired. Fair value is estimated based on the present value of future cash flows over several interest rate scenarios, which are then discounted at risk-adjusted rates. The Company considers portfolio characteristics, contractually specified servicing fees, prepayment assumptions, delinquency rates, late charges, other ancillary revenue, costs to service and other economic factors. When available, fair value estimates and assumptions are compared to observable market data and the recent market activity and actual portfolio experience.
	The following table summarizes financial assets and financial liabilities measured at fair value on a recurring basis as of March 31, 2014 and 2013, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value:
			Level 1			Level 2			Level 3		Total Fair
			Inputs			Inputs			Inputs		Value
			(Dollars in thousands)
	March 31, 2014
	Securities available for sale:
	U.S. Treasury		$	128,740		$	—		$	—	$	128,740
	U.S. federal agencies			—			346,793			—		346,793
	Mortgage-backed securities			—			12,277			17,587		29,864
	States and political subdivisions			—			54,971			—		54,971
	Other securities			—			3,482			11,899		15,381
	Derivative assets			—			3,072			—		3,072
	Derivative liabilities			—			1,667			—		1,667
	Loans held for sale			—			5,231			—		5,231
	Mortgage servicing intangibles			—			—			535		535
	March 31, 2013
	Securities available for sale:
	U.S. Treasury		$	20,304		$	—		$	—	$	20,304
	U.S. federal agencies			—			442,075			—		442,075
	Mortgage-backed securities			—			17,974			—		17,974
	States and political subdivisions			—			55,493			—		55,493
	Other securities			—			3,421			10,124		13,545
	Derivative assets			—			3,424			—		3,424
	Derivative liabilities			—			1,658			—		1,658
	Loans held for sale			—			7,211			—		7,211
	Mortgage servicing intangibles			—			—			709		709
	The changes in Level 3 assets measured at estimated fair value on a recurring basis during the three months ended March 31, 2014 and 2013 were as follows:
			Three Months Ended
			March 31
			2014			2013
			(Dollars in thousands)
	Balance at the beginning of the year		$	32,002		$	10,779
	Purchases, issuances and settlements			(1,847	)		116
	Sales			(499	)		(15	)
	Gains included in earnings			417			(30	)
	Total unrealized losses			(52	)		(17	)
	Balance at the end of the period		$	30,021		$	10,833
	The Company’s policy is to recognize transfers in and transfers out of Levels 1, 2 and 3 as of the end of the reporting period. During the three months ended March 31, 2014 and 2013, the Company did not transfer any securities between levels in the fair value hierarchy.
	Financial Assets and Financial Liabilities Measured at Fair Value on a Nonrecurring Basis
	Certain financial assets and financial liabilities are measured at fair value on a nonrecurring basis; that is, the instruments are not measured at fair value on an ongoing basis but are subject to fair value adjustments in certain circumstances (for example, when there is evidence of impairment). These financial assets and financial liabilities are reported at fair value utilizing Level 3 inputs.
	Impaired loans are reported at the fair value of the underlying collateral if repayment is dependent on liquidation of the collateral. In no case does the fair value of an impaired loan exceed the fair value of the underlying collateral. The impaired loans are adjusted to fair value through a specific allocation of the allowance for loan losses or a direct charge-down of the loan.
	Foreclosed assets, upon initial recognition, are measured and adjusted to fair value through a charge-off to the allowance for possible loan losses based upon the fair value of the foreclosed asset.
	Other real estate owned is revalued at fair value subsequent to initial recognition, with any losses recognized in net expense from other real estate owned.
	The following table summarizes assets measured at fair value on a nonrecurring basis and the related gains or losses recognized during the period:
			Level 1			Level 2			Level 3		Total		Gains
											Fair		(Losses)
Value
		(Dollars in thousands)
Three Months Ended March 31, 2014
Impaired loans (less specific allowance)			—			—		$	38,807	$	38,807	$	—
Foreclosed assets			—			—			262		262		(12	)
Other real estate owned			—			—			7,328		7,328		(517	)
Three Months Ended March 31, 2013
Impaired loans (less specific allowance)			—			—		$	40,852	$	40,852	$	—
Foreclosed assets			—			—			326		326		13
Other real estate owned			—			—			9,098		9,098		(87	)
Estimated Fair Value of Financial Instruments
The Company is required under current authoritative accounting guidance to disclose the estimated fair value of their financial instruments that are not recorded at fair value. For the Company, as for most financial institutions, substantially all of its assets and liabilities are considered financial instruments. A financial instrument is defined as cash, evidence of an ownership interest in an entity or a contract that creates a contractual obligation or right to deliver or receive cash or another financial instrument from a second entity. The following methods and assumptions were used to estimate the fair value of each class of financial instruments:
Cash and Cash Equivalents Include: Cash and Due from Banks, Federal Funds Sold and Interest-Bearing Deposits
The carrying amount of these short-term instruments is a reasonable estimate of fair value.
Securities Held for Investment
For securities held for investment, which are generally traded in secondary markets, fair values are based on quoted market prices or dealer quotes, if available. If a quoted market price is not available, fair value is estimated using quoted market prices for similar securities making adjustments for credit or liquidity if applicable.
Loans
For certain homogeneous categories of loans, such as some residential mortgages, fair values are estimated using the quoted market prices for securities backed by similar loans, adjusted for differences in loan characteristics. The fair values of other types of loans are estimated by discounting the future cash flows using the current rates at which similar loans would be made to borrowers with similar credit ratings and for the same remaining maturities.
Deposits
The fair values of transaction and savings accounts are the amounts payable on demand at the reporting date. The fair values of fixed-maturity certificates of deposit are estimated using the rates currently offered for deposits of similar remaining maturities.
Short-term Borrowings
The amounts payable on these short-term instruments are reasonable estimates of fair value.
Long-term Borrowings
The fair values of fixed-rate long-term borrowings are estimated using the rates that would be charged for borrowings of similar remaining maturities.
Junior Subordinated Debentures
The fair values of junior subordinated debentures are estimated using the rates that would be charged for junior subordinated debentures of similar remaining maturities.
Loan Commitments and Letters of Credit
The fair values of commitments are estimated using the fees currently charged to enter into similar agreements, taking into account the terms of the agreements. The fair values of letters of credit are based on fees currently charged for similar agreements.
The estimated fair values of the Company’s financial instruments that are reported at amortized cost in the Company’s consolidated balance sheets, segregated by the level of valuation inputs within the fair value hierarchy utilized to measure fair value, are as follows:
		March 31,
		2014						2013
		Carrying			Fair Value			Carrying		Fair Value
		Amount						Amount
		(Dollars in thousands)
FINANCIAL ASSETS
Level 2 inputs:
Cash and cash equivalents		$	1,966,106		$	1,966,106		$	1,716,052	$	1,716,052
Securities held for investment			11,269			11,351			16,099		16,317
Level 3 inputs:
Loans, net			3,502,346			3,424,944			3,181,303		3,240,479
FINANCIAL LIABILITIES
Level 2 inputs:
Deposits			5,737,850			5,538,503			5,174,512		5,200,273
Short-term borrowings			8,603			8,603			4,891		4,891
Long-term borrowings			2,000			1,997			11,040		11,010
Junior subordinated debentures			26,804			28,948			26,804		31,093
OFF-BALANCE SHEET FINANCIAL INSTRUMENTS
Loan commitments						1,712					1,556
Letters of credit						459					469
Non-financial Assets and Non-financial Liabilities Measured at Fair Value
The Company has no non-financial assets or non-financial liabilities measured at fair value on a recurring basis. Certain non-financial assets and non-financial liabilities measured at fair value on a nonrecurring basis include intangible assets (excluding mortgage service rights which are valued quarterly) and other non-financial long-lived assets measured at fair value and adjusted for impairment. These items are evaluated at least annually for impairment. The overall levels of non-financial assets and non-financial liabilities measured at fair value on a nonrecurring basis were not considered to be significant to the Company at March 31, 2014 or 2013.

DERIVATIVE_FINANCIAL_INSTRUMEN

DERIVATIVE FINANCIAL INSTRUMENTS	3 Months Ended
	Mar. 31, 2014
Derivative Instruments And Hedging Activities Disclosure [Abstract]	'
DERIVATIVE FINANCIAL INSTRUMENTS	'
	-10	DERIVATIVE FINANCIAL INSTRUMENTS
	The Company enters into oil and gas swaps and options contracts to accommodate the business needs of its customers. Upon the origination of an oil or gas swap or option contract with a customer, the Company simultaneously enters into an offsetting contract with a counterparty to mitigate the exposure to fluctuations in oil and gas prices. These derivatives are not designated as hedged instruments and are recorded on the Company’s consolidated balance sheet at fair value.
	The Company utilizes dealer quotations and observable market data inputs to substantiate internal valuation models. The notional amounts and estimated fair values of oil and gas derivative positions outstanding are presented in the following table:
			March 31, 2014
	Oil and Natural Gas Swaps and Options		Notional Units		Notional				Estimated
					Amount				Fair
									Value
			(Notional amounts and dollars in thousands)
	Oil
	Derivative assets		Barrels			310			$	981
	Derivative liabilities		Barrels			(310	)			(572	)
	Natural Gas
	Derivative assets		MMBTUs			2,731				2,091
	Derivative liabilities		MMBTUs			(2,731	)			(1,095	)
	Total Fair Value		Included in
	Derivative assets		Other assets							3,072
	Derivative liabilities		Other liabilities							(1,667	)
	The following table is a summary of the Company’s recognized income related to the activity, which was included in other noninterest income:
			Three Months Ended March 31,
			2014				2013
			(Dollars in thousands)
	Derivative income		$	149			$	108
	The Company’s credit exposure on oil and gas swaps and options varies based on the current market prices of oil and natural gas. Other than credit risk, changes in the fair value of customer positions will be offset by equal and opposite changes in the counterparty positions. The net positive fair value of the contracts represents the profit derived from the activity and is unaffected by market price movements.
	Customer credit exposure is managed by strict position limits and is primarily offset by first liens on production while the remainder is offset by cash. Counterparty credit exposure is managed by selecting highly rated counterparties (rated A- or better by Standard and Poor’s) and monitoring market information.
	The following table is a summary of the Company’s net credit exposure relating to oil and gas swaps and options with bank customers:
			March 31, 2014
			(Dollars in thousands)
	Credit exposure		$	2,974
	Balance Sheet Offsetting
	Derivatives may be eligible for offset in the consolidated balance sheet and/or subject to master netting arrangements. The Company’s derivative transactions with upstream financial institution counterparties and bank customers are generally executed under International Swaps and Derivative Association (“ISDA”) master agreements which include “right of set-off” provisions. In such cases there is generally a legally enforceable right to offset recognized amounts and there may be an intention to settle such amounts on a net basis. Nonetheless, the Company does not generally offset such financial instruments for financial reporting purposes.

SEGMENT_INFORMATION

SEGMENT INFORMATION	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
SEGMENT INFORMATION	'
	-11	SEGMENT INFORMATION
	The Company evaluates its performance with an internal profitability measurement system that measures the profitability of its business units on a pre-tax basis. The four principal business units are metropolitan banks, community banks, other financial services, and executive, operations and support. Metropolitan and community banks offer traditional banking products such as commercial and retail lending, and a full line of deposit accounts. Metropolitan banks consist of banking locations in the metropolitan Oklahoma City and Tulsa areas. Community banks consist of banking locations in communities throughout Oklahoma. Other financial services are specialty product business units including guaranteed small business lending, residential mortgage lending, trust services, securities brokerage, electronic banking and insurance. The executive, operations and support groups represent executive management, operational support and corporate functions that are not allocated to the other business units.
	The results of operations and selected financial information for the four business units are as follows:
			Metropolitan		Community		Other		Executive,			Eliminations			Consolidated
			Banks		Banks		Financial		Operations
							Services		& Support
			(Dollars in thousands)
	Three Months Ended March 31, 2014
	Net interest income (expense)		$	13,787	$	27,241	$	1,376	$	(375	)	$	—		$	42,029
	Noninterest income			3,413		12,266		7,056		15,955			(15,128	)		23,562
	Income before taxes			7,790		15,077		3,066		9,679			(15,075	)		20,537
	Three Months Ended March 31, 2013
	Net interest income (expense)		$	14,011	$	25,144	$	1,565	$	(464	)	$	—		$	40,256
	Noninterest income			3,190		11,545		6,902		14,749			(13,851	)		22,535
	Income before taxes			8,937		14,077		3,237		8,094			(13,798	)		20,547
	Total Assets:
	March 31, 2014		$	2,093,563	$	3,973,407	$	113,732	$	816,489		$	(622,150	)	$	6,375,041
	December 31, 2013			2,079,444		3,764,429		103,656		703,294			(611,849	)		6,038,974
	March 31, 2013			1,926,511		3,627,011		109,887		690,318			(579,801	)		5,773,926
	The financial information for each business unit is presented on the basis used internally by management to evaluate performance and allocate resources. The Company utilizes a transfer pricing system to allocate the benefit or cost of funds provided or used by the various business units. Certain services provided by the support group to other business units, such as item processing, are allocated at rates approximating the cost of providing the services. Eliminations are adjustments to consolidate the business units and companies. Capital expenditures are generally charged to the business unit using the asset.

DESCRIPTION_OF_BUSINESS_AND_SU1

DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	3 Months Ended
	Mar. 31, 2014
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., BancFirst Agency, Inc. and BancFirst Community Development Corporation. 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, 2013, should be referred to in connection with these unaudited interim consolidated financial statements.
	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, 2013, the date of the most recent annual report.
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.
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.
Recent Accounting Pronouncements	'
	Recent Accounting Pronouncements
	In January 2014, the Financial Accounting Standards Board (“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 are effective for annual periods, and interim reporting periods within those annual periods, beginning after December 15, 2014. The amendments may be adopted using either a modified retrospective transition method or a prospective transition method. Early adoption is permitted. Adoption of ASU 2014-04 is not expected to 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 are effective for annual periods, and interim reporting periods within those annual periods, beginning after December 15, 2014. The amendments are required to be applied retrospectively to all periods presented. Early adoption is permitted. Adoption of ASU 2014-01 is not expected to have a significant effect on the Company’s financial statements.
	In February 2013, the FASB issued ASU No. 2013-02, “Comprehensive Income (Topic 220).” ASU 2013-02 requires an entity to provide information about the amounts reclassified out of accumulated other comprehensive income by component. An entity is required to present, either on the face of the statement where net income is presented or in the notes, significant amounts reclassified out of accumulated other comprehensive income by the respective line items of net income but only if the amount reclassified is required under U.S. GAAP to be reclassified to net income in its entirety in the same reporting period. The new standard was effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2012. Adoption of ASU 2013-02 did not have a significant effect on the Company’s financial statements.

SECURITIES_Tables

SECURITIES (Tables)	3 Months Ended
	Mar. 31, 2014
Investments Debt And Equity Securities [Abstract]	'
Summary of Securities Held for Investment and Securities Available for Sale	'
	The following table summarizes securities held for investment and securities available for sale:
			March 31, 2014
			(Dollars in thousands)
	Held for investment, at cost (fair value: $11,351)		$	11,269
	Available for sale, at fair value			575,749
	Total		$	587,018
Summary of Amortized Cost and Estimated Fair Values of Securities Held for Investment	'
	The following table summarizes the amortized cost and estimated fair values of securities held for investment:
			March 31, 2014
			Amortized		Gross		Gross			Estimated
			Cost		Unrealized		Unrealized			Fair
					Gains		Losses			Value
			(Dollars in thousands)
	Mortgage backed securities (1)		$	575	$	41	$	—		$	616
	States and political subdivisions			10,694		48		(7	)		10,735
	Total		$	11,269	$	89	$	(7	)	$	11,351
Summary of Amortized Cost and Estimated Fair Values of Securities Available for Sale	'
	The following table summarizes the amortized cost and estimated fair values of securities available for sale:
			March 31, 2014
			Amortized		Gross		Gross			Estimated
			Cost		Unrealized		Unrealized			Fair
					Gains		Losses			Value
			(Dollars in thousands)
	U.S. treasury and other federal agencies		$	474,579	$	1,452	$	(498	)	$	475,533
	Mortgage backed securities (1)			29,228		637		(1	)		29,864
	States and political subdivisions			53,456		1,583		(68	)		54,971
	Other securities (2)			12,060		3,462		(141	)		15,381
	Total		$	569,323	$	7,134	$	(708	)	$	575,749
	-1	Primarily consists of FHLMC, FNMA, GNMA and mortgage backed securities through U.S. agencies.
	-2	Primarily consists of equity securities.
Maturity of Securities	'
	The maturities of securities held for investment and available for sale are summarized in the following table using contractual maturities.
			March 31, 2014
			Amortized		Estimated
			Cost		Fair
					Value
			(Dollars in thousands)
	Held for Investment
	Contractual maturity of debt securities:
	Within one year		$	3,190	$	3,193
	After one year but within five years			7,240		7,274
	After five years but within ten years			639		662
	After ten years			200		222
	Total		$	11,269	$	11,351
	Available for Sale
	Contractual maturity of debt securities:
	Within one year		$	172,145	$	172,418
	After one year but within five years			267,092		267,938
	After five years but within ten years			27,354		28,056
	After ten years			94,085		95,439
	Total debt securities			560,676		563,851
	Equity securities			8,647		11,898
	Total		$	569,323	$	575,749
Company's Book Value of Pledged Securities	'
	The following table is a summary of the Company’s book value of securities that were pledged as collateral for public funds on deposit, repurchase agreements and for other purposes as required or permitted by law:
			March 31, 2014
			(Dollars in thousands)
	Book value of pledged securities		$	434,972

LOANS_AND_ALLOWANCE_FOR_LOAN_L1

LOANS AND ALLOWANCE FOR LOAN LOSSES (Tables)	3 Months Ended
	Mar. 31, 2014
Receivables [Abstract]	'
Schedule of Loans Outstanding by Category	'
	The following is a schedule of loans outstanding by category:
		March 31, 2014						December 31, 2013						March 31, 2013
		Amount			Percent			Amount			Percent			Amount			Percent
		(Dollars in thousands)
	Commercial and industrial	$	676,084			19.09	%	$	605,672			17.88	%	$	518,438			16.1	%
	Oil & gas production & equipment		99,382			2.8			96,907			2.86			154,392			4.79
	Agriculture		109,570			3.09			111,323			3.29			96,094			2.98
	State and political subdivisions:
	Taxable		9,824			0.28			10,217			0.3			9,272			0.29
	Tax-exempt		11,219			0.32			11,073			0.33			13,034			0.41
	Real estate:
	Construction		299,238			8.45			284,808			8.41			231,770			7.2
	Farmland		141,059			3.98			132,512			3.91			124,347			3.86
	One to four family residences		723,358			20.42			703,903			20.78			680,129			21.12
	Multifamily residential properties		60,785			1.72			60,080			1.77			47,506			1.48
	Commercial		1,134,384			32.02			1,097,484			32.4			1,084,864			33.69
	Consumer		251,651			7.1			250,588			7.4			240,600			7.47
	Other (not classified above)		25,716			0.73			22,579			0.67			19,521			0.61
	Total loans	$	3,542,270			100	%	$	3,387,146			100	%	$	3,219,967			100	%
	Loans held for sale (included above)	$	5,231					$	6,469					$	7,211
Summary of Nonperforming and Restructured Assets	'
	The following is a summary of nonperforming and restructured assets:
		March 31,			December 31,			March 31,
		2014			2013			2013
		(Dollars in thousands)
	Past due 90 days or more and still accruing	$	910		$	1,179		$	542
	Nonaccrual		17,753			14,390			20,933
	Restructured		17,468			17,624			17,792
	Total nonperforming and restructured loans		36,131			33,193			39,267
	Other real estate owned and repossessed assets		7,590			8,386			9,424
	Total nonperforming and restructured assets	$	43,721		$	41,579		$	48,691
	Nonperforming and restructured loans to total loans		1.02	%		0.98	%		1.22	%
	Nonperforming and restructured assets to total assets		0.69	%		0.69	%		0.84	%
Summary of Amounts Included in Nonaccrual Loans Segregated by Class of Loans	'
	The following table is a summary of amounts included in nonaccrual loans, segregated by class of loans. Residential real estate refers to one-to-four family real estate.
		March 31, 2014			March 31, 2013
		(Dollars in thousands)
	Non-residential real estate owner occupied	$	448		$	382
	Non-residential real estate other		5,779			9,284
	Residential real estate permanent mortgage		689			619
	Residential real estate all other		958			3,716
	Non-consumer non-real estate		1,287			1,449
	Consumer non-real estate		165			187
	Other loans		1,198			3,052
	Acquired loans		7,229			2,244
	Total	$	17,753		$	20,933
Age Analysis of Past Due Loans Segregated by Class of Loans	'
	The following table presents an age analysis of past due loans, segregated by class of loans:
		Age Analysis of Past Due Loans
		30-89			90 Days			Total Past			Current			Total			Accruing
		Days Past			and			Due Loans			Loans			Loans			Loans
		Due			Greater												90 Days
																	or More
																	Past Due
		(Dollars in thousands)
	As of March 31, 2014
	Non-residential real estate owner occupied	$	518		$	298		$	816		$	457,978		$	458,794		$	96
	Non-residential real estate other		4,978			935			5,913			873,592			879,505			—
	Residential real estate permanent mortgage		1,867			458			2,325			270,879			273,204			76
	Residential real estate all other		1,274			543			1,817			565,930			567,747			86
	Non-consumer non-real estate		2,749			929			3,678			824,361			828,039			18
	Consumer non-real estate		2,151			260			2,411			223,551			225,962			218
	Other loans		2,080			337			2,417			145,794			148,211			—
	Acquired loans		3,053			4,608			7,661			153,147			160,808			416
	Total	$	18,670		$	8,368		$	27,038		$	3,515,232		$	3,542,270		$	910
	As of March 31, 2013
	Non-residential real estate owner occupied	$	1,230		$	112		$	1,342		$	452,461		$	453,803		$	18
	Non-residential real estate other		2,063			1,833			3,896			786,343			790,239			—
	Residential real estate permanent mortgage		2,351			460			2,811			245,945			248,756			163
	Residential real estate all other		2,087			408			2,495			522,542			525,037			105
	Non-consumer non-real estate		2,100			214			2,314			748,287			750,601			74
	Consumer non-real estate		1,994			184			2,178			209,142			211,320			126
	Other loans		2,152			1,406			3,558			140,468			144,026			—
	Acquired loans		1,993			328			2,321			93,864			96,185			56
	Total	$	15,970		$	4,945		$	20,915		$	3,199,052		$	3,219,967		$	542
Impaired Loans Segregated by Class of Loans	'
	The following table presents impaired loans, segregated by class of loans. No material amount of interest income was recognized on impaired loans subsequent to their classification as impaired.
		Impaired Loans
		Unpaid			Recorded			Related			Average
		Principal			Investment			Allowance			Recorded
		Balance			with Allowance						Investment
		(Dollars in thousands)
	As of March 31, 2014
	Non-residential real estate owner occupied	$	688		$	601		$	29		$	642
	Non-residential real estate other		24,355			22,680			1,734			22,915
	Residential real estate permanent mortgage		1,068			836			88			918
	Residential real estate all other		1,318			1,139			218			1,335
	Non-consumer non-real estate		1,824			1,491			427			1,449
	Consumer non-real estate		548			527			134			572
	Other loans		1,215			1,198			207			1,278
	Acquired loans		20,179			13,361			189			9,744
	Total	$	51,195		$	41,833		$	3,026		$	38,853
	As of March 31, 2013
	Non-residential real estate owner occupied	$	580		$	517		$	19		$	732
	Non-residential real estate other		27,369			25,900			2,166			26,082
	Residential real estate permanent mortgage		1,448			1,226			61			1,007
	Residential real estate all other		4,631			4,246			1,276			3,840
	Non-consumer non-real estate		1,899			1,565			452			2,249
	Consumer non-real estate		441			421			96			408
	Other loans		3,736			3,094			267			2,648
	Acquired loans		10,311			8,261			41			8,893
	Total	$	50,415		$	45,230		$	4,378		$	45,859
Internal Loan Grading by Class of Loans	'
	The following table presents internal loan grading by class of loans:
		Internal Loan Grading
		Grade
		1			2			3			4			5			Total
		(Dollars in thousands)
	As of March 31, 2014
	Non-residential real estate owner occupied	$	381,290		$	70,949		$	6,052		$	503		$	—		$	458,794
	Non-residential real estate other		724,181			129,390			20,155			5,779			—			879,505
	Residential real estate permanent mortgage		240,653			25,074			6,610			867			—			273,204
	Residential real estate all other		474,152			86,033			6,495			1,067			—			567,747
	Non-consumer non-real estate		673,757			147,625			5,350			1,307			—			828,039
	Consumer non-real estate		212,492			11,388			1,655			427			—			225,962
	Other loans		144,870			2,375			736			230			—			148,211
	Acquired loans		92,581			48,073			12,091			7,917			146			160,808
	Total	$	2,943,976		$	520,907		$	59,144		$	18,097		$	146		$	3,542,270
	As of March 31, 2013
	Non-residential real estate owner occupied	$	393,152		$	55,109		$	5,142		$	400		$	—		$	453,803
	Non-residential real estate other		649,917			110,186			20,852			9,284			—			790,239
	Residential real estate permanent mortgage		208,732			33,463			5,730			831			—			248,756
	Residential real estate all other		461,620			51,181			8,410			3,826			—			525,037
	Non-consumer non-real estate		647,162			97,110			4,800			1,529			—			750,601
	Consumer non-real estate		198,107			10,912			1,923			374			4			211,320
	Other loans		139,696			2,304			1,103			923			—			144,026
	Acquired loans		74,939			14,936			4,009			2,301			—			96,185
	Total	$	2,773,325		$	375,201		$	51,969		$	19,468		$	4		$	3,219,967
Activity in All by Class of Loans	'
	The following table details activity in the ALL by class of loans for the period presented. Allocation of a portion of the allowance to one category of loans does not preclude its availability to absorb losses in other catagories.
		ALL
		Balance at			Charge-			Recoveries			Net			Provisions			Balance
		beginning			offs						charge-			charged to			at end of
		of period									offs			operations			period
		(Dollars in thousands)
	Three Months Ended March 31, 2014
	Non-residential real estate owner occupied	$	4,827		$	(4	)	$	31		$	27		$	158		$	5,012
	Non-residential real estate other		11,026			—			3			3			(344	)		10,685
	Residential real estate permanent mortgage		2,825			(130	)		10			(120	)		532			3,237
	Residential real estate all other		6,708			(49	)		4			(45	)		(178	)		6,485
	Non-consumer non-real estate		8,977			(70	)		14			(56	)		782			9,703
	Consumer non-real estate		2,556			(140	)		62			(78	)		95			2,573
	Other loans		1,991			(64	)		17			(47	)		128			2,072
	Acquired loans		124			(17	)		5			(12	)		45			157
	Total	$	39,034		$	(474	)	$	146		$	(328	)	$	1,218		$	39,924
		ALL
		Balance at			Charge-			Recoveries			Net			Provisions			Balance
		beginning			offs						charge-			charged to			at end of
		of period									offs			operations			period
		(Dollars in thousands)
	Three Months Ended March 31, 2013
	Non-residential real estate owner occupied	$	5,104		$	—		$	15		$	15		$	(253	)	$	4,866
	Non-residential real estate other		9,865			(18	)		4			(14	)		614			10,465
	Residential real estate permanent mortgage		2,781			(56	)		11			(45	)		20			2,756
	Residential real estate all other		7,034			(95	)		2			(93	)		224			7,165
	Non-consumer non-real estate		9,385			(36	)		31			(5	)		(398	)		8,982
	Consumer non-real estate		2,451			(140	)		76			(64	)		(3	)		2,384
	Other loans		1,885			(139	)		—			(139	)		76			1,822
	Acquired loans		220			(49	)		33			(16	)		20			224
	Total	$	38,725		$	(533	)	$	172		$	(361	)	$	300		$	38,664
Allowance for Loan Losses Outstanding by Impairment Methodology	'
	The following table details the amount of ALL by class of loans for the period presented, on the basis of the impairment methodology used by the Company.
		ALL
		March 31, 2014						March 31, 2013
		Individually			Collectively			Individually			Collectively
		evaluated for			evaluated for			evaluated for			evaluated for
		impairment			impairment			impairment			impairment
		(Dollars in thousands)
	Non-residential real estate owner occupied	$	361		$	4,651		$	210		$	4,656
	Non-residential real estate other		1,929			8,756			2,484			7,981
	Residential real estate permanent mortgage		588			2,649			224			2,532
	Residential real estate all other		733			5,752			1,899			5,266
	Non-consumer non-real estate		1,133			8,570			1,211			7,771
	Consumer non-real estate		389			2,184			290			2,094
	Other loans		242			1,830			199			1,623
	Acquired loans		—			157			—			224
	Total	$	5,375		$	34,549		$	6,517		$	32,147
Loans Outstanding by Impairment Methodology	'
	The following table details the loans outstanding by class of loans for the period presented, on the basis of the impairment methodology used by the Company.
		Loans
		March 31, 2014									March 31, 2013
		Individually			Collectively			Loans acquired			Individually			Collectively			Loans acquired
		evaluated for			evaluated for			with			evaluated for			evaluated for			with
		impairment			impairment			deteriorated			impairment			impairment			deteriorated
								credit quality									credit quality
		(Dollars in thousands)
	Non-residential real estate owner occupied	$	6,555		$	452,239		$	—		$	5,542		$	448,261		$	—
	Non-residential real estate other		25,934			853,571			—			30,136			760,103			—
	Residential real estate permanent mortgage		7,477			265,727			—			6,561			242,195			—
	Residential real estate all other		7,562			560,185			—			12,236			512,801			—
	Non-consumer non-real estate		6,657			821,382			—			6,329			744,272			—
	Consumer non-real estate		2,082			223,880			—			2,301			209,019			—
	Other loans		308			147,903			—			246			143,780			—
	Acquired loans		—			140,654			20,154			—			89,875			6,310
	Total	$	56,575		$	3,465,541		$	20,154		$	63,351		$	3,150,306		$	6,310
Transfers from Loans to Other Real Estate Owned and Repossessed Assets	'
	Transfers from loans to other real estate owned and repossessed assets during the periods presented are summarized as follows:
		Three Months Ended
		March 31,
		2014			2013
		(Dollars in thousands)
	Other real estate owned	$	66		$	436
	Repossessed assets		327			209
	Total	$	393		$	645

INTANGIBLE_ASSETS_Tables

INTANGIBLE ASSETS (Tables)	3 Months Ended
	Mar. 31, 2014
Goodwill And Intangible Assets Disclosure [Abstract]	'
Summary of Intangible Assets	'
	The following is a summary of intangible assets:
		Gross		Accumulated			Net
		Carrying		Amortization			Carrying
		Amount					Amount
		(Dollars in thousands)
	As of March 31, 2014
	Core deposit intangibles	$	12,681	$	(4,938	)	$	7,743
	Customer relationship intangibles		5,699		(2,428	)		3,271
	Mortgage servicing intangibles		696		(161	)		535
	Total	$	19,076	$	(7,527	)	$	11,549
Summary of Goodwill by Business Segment	'
	The following is a summary of goodwill by business segment:
		Metropolitan		Community			Other		Executive,		Consolidated
		Banks		Banks			Financial		Operations
							Services		& Support
		(Dollars in thousands)
	As of March 31, 2014
	Balance at beginning of period	$	8,079	$	30,552		$	5,464	$	450	$	44,545
	Acquisitions		—		573			—		—		573
	Balance at end of period	$	8,079	$	31,125		$	5,464	$	450	$	45,118

STOCKBASED_COMPENSATION_Tables

STOCK-BASED COMPENSATION (Tables)	3 Months Ended
	Mar. 31, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Summary of Activity Under Stock Option Plan	'
	The following table is a summary of the activity under both the BancFirst ISOP and the BancFirst Directors’ Stock Option Plan:
		Options			Wgtd.		Wgtd. Avg.			Aggregate
					Avg.		Remaining			Intrinsic
					Exercise		Contractual			Value
					Price		Term
		(Dollars in thousands, except per share data)
	Three Months Ended March 31, 2014
	Outstanding at December 31, 2013		1,158,317		$	34.45
	Options granted		—			—
	Options exercised		(28,750	)		30.1
	Options canceled, forfeited or expired		—			—
	Outstanding at March 31, 2014		1,129,567			34.56		8.63	Yrs	$	24,931
	Exercisable at March 31, 2014		538,667			28.01		6.19	Yrs	$	15,415
Options Granted and Options Exercised Under Stock Option Plan	'
	The following table has additional information regarding options granted and options exercised under both the BancFirst ISOP and the BancFirst Directors’ Stock Option Plan:
		Three Months Ended
		March 31,
		2014			2013
		(Dollars in thousands)
	Weighted average grant-date fair value per share of options granted	$	—		$	—
	Total intrinsic value of options exercised		745			206
	Cash received from options exercised		865			142
	Tax benefit realized from options exercised		288			80
Stock-based Employee Compensation Expense	'
	The following table is a summary of the Company’s recorded stock-based compensation expense:
		Three Months Ended
		March 31,
		2014			2013
		(Dollars in thousands)
	Stock-based compensation expense	$	347		$	374
	Tax benefit		134			145
	Stock-based compensation expense, net of tax	$	213		$	229
Remaining Fair Value of Stock Options	'
	The Company will continue to amortize the remaining fair value of stock options over the remaining vesting period of approximately seven years. The following table shows the remaining fair value of stock options:
		March 31, 2014
		(Dollars in thousands)
	Fair value of stock options	$	4,778

STOCKHOLDERS_EQUITY_Tables

STOCKHOLDERS' EQUITY (Tables)	3 Months Ended
	Mar. 31, 2014
Equity [Abstract]	'
Summary of Shares Repurchased Under Stock Purchase Program	'
	The following table is a summary of the shares under the program:
		Three Months Ended
		March 31,
		2014		2013
	Number of shares repurchased		—		23,050
	Average price of shares repurchased		—	$	40.92
	Shares remaining to be repurchased		194,723		211,914
Required Capital Amounts and Company's Respective Ratios	'
	The actual and required capital amounts and ratios are shown in the following table:
		Actual					Required					To Be Well
							For Capital					Capitalized Under
							Adequacy					Prompt Corrective
							Purposes					Action Provisions
		Amount		Ratio			Amount		Ratio			Amount		Ratio
		(Dollars in thousands)
	As of March 31, 2014:
	Total Capital
	(to Risk Weighted Assets)-
	BancFirst Corporation.	$	573,963		14.52	%	$	316,297		8	%		N/A		N/A
	BancFirst		537,600		13.62	%		315,685		8	%	$	394,606		10	%
	Tier 1 Capital
	(to Risk Weighted Assets)-
	BancFirst Corporation		534,039		13.51	%		158,148		4	%		N/A		N/A
	BancFirst		497,676		12.61	%		157,842		4	%		236,763		6	%
	Tier 1 Capital
	(to Total Assets)-
	BancFirst Corporation		534,039		8.45	%		191,252		3	%		N/A		N/A
	BancFirst		497,676		7.89	%		190,650		3	%		317,750		5	%

NET_INCOME_PER_COMMON_SHARE_Ta

NET INCOME PER COMMON SHARE (Tables)	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
Basic and Diluted Net Income Per Common Share	'
	Basic and diluted net income per common share are calculated as follows:
		Income		Shares		Per
		(Numerator)		(Denominator)		Share
						Amount
		(Dollars in thousands, except per share data)
	Three Months Ended March 31, 2014
	Basic
	Income available to common stockholders	$	14,657		15,342,486	$	0.96
	Effect of stock options		—		318,434
	Diluted
	Income available to common stockholders plus assumed exercises of stock options	$	14,657		15,660,920	$	0.94
	Three Months Ended March 31, 2013
	Basic
	Income available to common stockholders	$	13,372		15,238,701	$	0.88
	Effect of stock options		—		243,816
	Diluted
	Income available to common stockholders plus assumed exercises of stock options	$	13,372		15,482,517	$	0.86
Average Exercise Price of Options Excluded from Computation of Diluted Net Income Per Common Share	'
	The following table shows the number and average exercise price of options that were excluded from the computation of diluted net income per common share for each period because the options’ exercise prices were greater than the average market price of the common shares:
		Shares		Average
				Exercise Price
	Three Months Ended March 31, 2014		65,000	$	54.01
	Three Months Ended March 31, 2013		534,000		39.44

FAIR_VALUE_MEASUREMENTS_Tables

FAIR VALUE MEASUREMENTS (Tables)	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Fair Value of Financial Assets and Liabilities Measured on Recurring Basis	'
	The following table summarizes financial assets and financial liabilities measured at fair value on a recurring basis as of March 31, 2014 and 2013, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value:
		Level 1			Level 2			Level 3		Total Fair
		Inputs			Inputs			Inputs		Value
		(Dollars in thousands)
	March 31, 2014
	Securities available for sale:
	U.S. Treasury	$	128,740		$	—		$	—	$	128,740
	U.S. federal agencies		—			346,793			—		346,793
	Mortgage-backed securities		—			12,277			17,587		29,864
	States and political subdivisions		—			54,971			—		54,971
	Other securities		—			3,482			11,899		15,381
	Derivative assets		—			3,072			—		3,072
	Derivative liabilities		—			1,667			—		1,667
	Loans held for sale		—			5,231			—		5,231
	Mortgage servicing intangibles		—			—			535		535
	March 31, 2013
	Securities available for sale:
	U.S. Treasury	$	20,304		$	—		$	—	$	20,304
	U.S. federal agencies		—			442,075			—		442,075
	Mortgage-backed securities		—			17,974			—		17,974
	States and political subdivisions		—			55,493			—		55,493
	Other securities		—			3,421			10,124		13,545
	Derivative assets		—			3,424			—		3,424
	Derivative liabilities		—			1,658			—		1,658
	Loans held for sale		—			7,211			—		7,211
	Mortgage servicing intangibles		—			—			709		709
Changes in Level 3 Assets Measured at Estimated Fair Value on Recurring Basis	'
	The changes in Level 3 assets measured at estimated fair value on a recurring basis during the three months ended March 31, 2014 and 2013 were as follows:
		Three Months Ended
		March 31
		2014			2013
		(Dollars in thousands)
	Balance at the beginning of the year	$	32,002		$	10,779
	Purchases, issuances and settlements		(1,847	)		116
	Sales		(499	)		(15	)
	Gains included in earnings		417			(30	)
	Total unrealized losses		(52	)		(17	)
	Balance at the end of the period	$	30,021		$	10,833
Assets Measured at Fair Value on Nonrecurring Basis	'
	The following table summarizes assets measured at fair value on a nonrecurring basis and the related gains or losses recognized during the period:
		Level 1			Level 2			Level 3		Total		Gains
										Fair		(Losses)
										Value
		(Dollars in thousands)
	Three Months Ended March 31, 2014
	Impaired loans (less specific allowance)		—			—		$	38,807	$	38,807	$	—
	Foreclosed assets		—			—			262		262		(12	)
	Other real estate owned		—			—			7,328		7,328		(517	)
	Three Months Ended March 31, 2013
	Impaired loans (less specific allowance)		—			—		$	40,852	$	40,852	$	—
	Foreclosed assets		—			—			326		326		13
	Other real estate owned		—			—			9,098		9,098		(87	)
Estimated Fair Values of Company's Financial Instruments	'
	The estimated fair values of the Company’s financial instruments that are reported at amortized cost in the Company’s consolidated balance sheets, segregated by the level of valuation inputs within the fair value hierarchy utilized to measure fair value, are as follows:
		March 31,
		2014						2013
		Carrying			Fair Value			Carrying		Fair Value
		Amount						Amount
		(Dollars in thousands)
	FINANCIAL ASSETS
	Level 2 inputs:
	Cash and cash equivalents	$	1,966,106		$	1,966,106		$	1,716,052	$	1,716,052
	Securities held for investment		11,269			11,351			16,099		16,317
	Level 3 inputs:
	Loans, net		3,502,346			3,424,944			3,181,303		3,240,479
	FINANCIAL LIABILITIES
	Level 2 inputs:
	Deposits		5,737,850			5,538,503			5,174,512		5,200,273
	Short-term borrowings		8,603			8,603			4,891		4,891
	Long-term borrowings		2,000			1,997			11,040		11,010
	Junior subordinated debentures		26,804			28,948			26,804		31,093
	OFF-BALANCE SHEET FINANCIAL INSTRUMENTS
	Loan commitments					1,712					1,556
	Letters of credit					459					469

DERIVATIVE_FINANCIAL_INSTRUMEN1

DERIVATIVE FINANCIAL INSTRUMENTS (Tables)	3 Months Ended
	Mar. 31, 2014
Derivative Instruments And Hedging Activities Disclosure [Abstract]	'
Notional Amounts and Estimated Fair Values of Outstanding Derivative Positions	'
	The notional amounts and estimated fair values of oil and gas derivative positions outstanding are presented in the following table:
		March 31, 2014
	Oil and Natural Gas Swaps and Options	Notional Units		Notional				Estimated
				Amount				Fair Value
		(Notional amounts and dollars in thousands)
	Oil
	Derivative assets	Barrels			310			$	981
	Derivative liabilities	Barrels			(310	)			(572	)
	Natural Gas
	Derivative assets	MMBTUs			2,731				2,091
	Derivative liabilities	MMBTUs			(2,731	)			(1,095	)
	Total Fair Value	Included in
	Derivative assets	Other assets							3,072
	Derivative liabilities	Other liabilities							(1,667	)
Recognized Derivative Income Included in Other Noninterest Income	'
	The following table is a summary of the Company’s recognized income related to the activity, which was included in other noninterest income:
		Three Months Ended March 31,
		2014				2013
		(Dollars in thousands)
	Derivative income	$	149			$	108
Summary of Company's Net Credit Exposure Relating to Oil and Gas Swaps	'
	The following table is a summary of the Company’s net credit exposure relating to oil and gas swaps and options with bank customers:
		March 31, 2014
		(Dollars in thousands)
	Credit exposure	$	2,974

SEGMENT_INFORMATION_Tables

SEGMENT INFORMATION (Tables)	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Results of Operations and Selected Financial Information	'
	The results of operations and selected financial information for the four business units are as follows:
		Metropolitan		Community		Other		Executive,			Eliminations			Consolidated
		Banks		Banks		Financial		Operations
						Services		& Support
		(Dollars in thousands)
	Three Months Ended March 31, 2014
	Net interest income (expense)	$	13,787	$	27,241	$	1,376	$	(375	)	$	—		$	42,029
	Noninterest income		3,413		12,266		7,056		15,955			(15,128	)		23,562
	Income before taxes		7,790		15,077		3,066		9,679			(15,075	)		20,537
	Three Months Ended March 31, 2013
	Net interest income (expense)	$	14,011	$	25,144	$	1,565	$	(464	)	$	—		$	40,256
	Noninterest income		3,190		11,545		6,902		14,749			(13,851	)		22,535
	Income before taxes		8,937		14,077		3,237		8,094			(13,798	)		20,547
	Total Assets:
	March 31, 2014	$	2,093,563	$	3,973,407	$	113,732	$	816,489		$	(622,150	)	$	6,375,041
	December 31, 2013		2,079,444		3,764,429		103,656		703,294			(611,849	)		6,038,974
	March 31, 2013		1,926,511		3,627,011		109,887		690,318			(579,801	)		5,773,926

Recovered_Sheet1

Recent Developments Including Mergers and Acquisitions - Additional Information (Detail) (BancFirst [Member], USD $)	Mar. 31, 2014	Jan. 24, 2014
In Millions, unless otherwise specified
Business Combination, Separately Recognized Transactions [Line Items]	'	'
Deposits	$231	$302
Loans	'	121
Securities	'	4.8
Other real estate	'	0.01
Performing [Member]	'	'
Business Combination, Separately Recognized Transactions [Line Items]	'	'
Loans	$98.80	'

Securities_Summary_of_Securiti

Securities - Summary of Securities Held for Investment and Securities Available for Sale (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
In Thousands, unless otherwise specified
Marketable Securities [Abstract]	'	'	'
Held for investment, at cost (fair value: $11,351)	$11,269	'	'
Available for sale, at fair value	575,749	'	'
Total	$587,018	$527,627	$565,490

Securities_Summary_of_Securiti1

Securities - Summary of Securities Held for Investment and Securities Available for Sale (Parenthetical) (Detail) (USD $)	Mar. 31, 2014
In Thousands, unless otherwise specified
Marketable Securities [Abstract]	'
Held for investment at fair value	$11,351

Securities_Summary_of_Amortize

Securities - Summary of Amortized Cost and Estimated Fair Values of Securities Held for Investment (Detail) (USD $)	Mar. 31, 2014
In Thousands, unless otherwise specified
Schedule of Held-to-maturity Securities [Line Items]	'
Amortized Cost	$11,269
Gross Unrealized Gains	89
Gross Unrealized Losses	-7
Estimated Fair Value	11,351
Mortgage-backed securities [Member]	'
Schedule of Held-to-maturity Securities [Line Items]	'
Amortized Cost	575
Gross Unrealized Gains	41
Gross Unrealized Losses	'
Estimated Fair Value	616
States and political subdivisions [Member]	'
Schedule of Held-to-maturity Securities [Line Items]	'
Amortized Cost	10,694
Gross Unrealized Gains	48
Gross Unrealized Losses	-7
Estimated Fair Value	$10,735

Securities_Summary_of_Amortize1

Securities - Summary of Amortized Cost and Estimated Fair Values of Securities Available for Sale (Detail) (USD $)	Mar. 31, 2014	Mar. 31, 2013
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	$569,323	'
Gross Unrealized Gains	7,134	'
Gross Unrealized Losses	-708	'
Estimated Fair Value, Total	575,749	'
U S Treasury and Other Federal Agencies [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	474,579	'
Gross Unrealized Gains	1,452	'
Gross Unrealized Losses	-498	'
Estimated Fair Value, Total	475,533	'
Mortgage-backed securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	29,228	'
Gross Unrealized Gains	637	'
Gross Unrealized Losses	-1	'
Estimated Fair Value, Total	29,864	17,974
States and political subdivisions [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	53,456	'
Gross Unrealized Gains	1,583	'
Gross Unrealized Losses	-68	'
Estimated Fair Value, Total	54,971	'
Other securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	12,060	'
Gross Unrealized Gains	3,462	'
Gross Unrealized Losses	-141	'
Estimated Fair Value, Total	$15,381	'

Securities_Maturity_of_Securit

Securities - Maturity of Securities (Detail) (USD $)	Mar. 31, 2014
In Thousands, unless otherwise specified
Amortized Cost And Fair Value Debt Securities [Abstract]	'
Amortized cost, Within one year	$3,190
Amortized cost, After one year but within five years	7,240
Amortized cost, After five years but within ten years	639
Amortized cost, After ten years	200
Amortized cost, Total	11,269
Amortized Cost, Within one year	172,145
Amortized Cost, After one year but within five years	267,092
Amortized Cost, After five years but within ten years	27,354
Amortized Cost, After ten years	94,085
Total debt securities	560,676
Amortized Cost, Equity securities	8,647
Amortized Cost, Total	569,323
Estimated Fair Value, Within one year	3,193
Estimated Fair Value, After one year but within five years	7,274
Estimated Fair Value, After five years but within ten years	662
Estimated Fair Value, After ten years	222
Estimated Fair Value	11,351
Estimated Fair Value, Within one year	172,418
Estimated Fair Value, After one year but within five years	267,938
Estimated Fair Value, After five years but within ten years	28,056
Estimated Fair Value, After ten years	95,439
Total debt securities	563,851
Estimated Fair Value, Equity securities	11,898
Estimated Fair Value, Total	$575,749

Securities_Companys_Book_Value

Securities - Company's Book Value of Pledged Securities (Detail) (USD $)	Mar. 31, 2014
In Thousands, unless otherwise specified
Pledged Financial Instruments Not Separately Reported Securities Pledged By Type Of Security [Abstract]	'
Book value of pledged securities	$434,972

Recovered_Sheet2

Loans and Allowance for Loan Losses - Schedule of Loans Outstanding by Category (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
In Thousands, unless otherwise specified
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Loans held for sale (included above)	$5,231	$6,469	$7,211
Total loans	3,542,270	3,387,146	3,219,967
Percent	100.00%	100.00%	100.00%
Taxable [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	9,824	10,217	9,272
Percent	0.28%	0.30%	0.29%
Tax-exempt [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	11,219	11,073	13,034
Percent	0.32%	0.33%	0.41%
Commercial and industrial [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	676,084	605,672	518,438
Percent	19.09%	17.88%	16.10%
Agriculture [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	109,570	111,323	96,094
Percent	3.09%	3.29%	2.98%
Construction [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	299,238	284,808	231,770
Percent	8.45%	8.41%	7.20%
Farmland [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	141,059	132,512	124,347
Percent	3.98%	3.91%	3.86%
One to four family residences [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	723,358	703,903	680,129
Percent	20.42%	20.78%	21.12%
Multifamily residential properties [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	60,785	60,080	47,506
Percent	1.72%	1.77%	1.48%
Commercial [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	1,134,384	1,097,484	1,084,864
Percent	32.02%	32.40%	33.69%
Consumer [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	251,651	250,588	240,600
Percent	7.10%	7.40%	7.47%
Other (not classified above) [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	25,716	22,579	19,521
Percent	0.73%	0.67%	0.61%
Oil & gas production & equipment [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	$99,382	$96,907	$154,392
Percent	2.80%	2.86%	4.79%

Recovered_Sheet3

Loans and Allowance for Loan Losses - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
	SecurityLoan
Receivables [Abstract]	'	'
Percentage of loans secured by real estate	60.00%	'
Interest income recognized	$227,000	$301,000
Troubled debt restructuring principal deferral	1	'
Interest income on impaired loans	$0	$0

Loans_and_Allowance_for_Loan_L2

Loans and Allowance for Loan Losses - Summary of Nonperforming and Restructured Assets (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
In Thousands, unless otherwise specified
Summary Of Nonperforming And Restructured Assets [Abstract]	'	'	'
Past due 90 days or more and still accruing	$910	$1,179	$542
Nonaccrual	17,753	14,390	20,933
Restructured	17,468	17,624	17,792
Total nonperforming and restructured loans	36,131	33,193	39,267
Other real estate owned and repossessed assets	7,590	8,386	9,424
Total nonperforming and restructured assets	$43,721	$41,579	$48,691
Nonperforming and restructured loans to total loans	1.02%	0.98%	1.22%
Nonperforming and restructured assets to total assets	0.69%	0.69%	0.84%

Loans_and_Allowance_for_Loan_L3

Loans and Allowance for Loan Losses - Summary of Amounts Included in Nonaccrual Loans Segregated by Class of Loans (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
In Thousands, unless otherwise specified
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'	'
Nonaccrual loans, Total	$17,753	$14,390	$20,933
Non-residential real estate owner occupied [Member]	'	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'	'
Nonaccrual loans, Total	448	'	382
Non-residential real estate other [Member]	'	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'	'
Nonaccrual loans, Total	5,779	'	9,284
Residential real estate permanent mortgage [Member]	'	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'	'
Nonaccrual loans, Total	689	'	619
Residential real estate all other [Member]	'	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'	'
Nonaccrual loans, Total	958	'	3,716
Non-consumer non-real estate [Member]	'	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'	'
Nonaccrual loans, Total	1,287	'	1,449
Consumer non-real estate [Member]	'	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'	'
Nonaccrual loans, Total	165	'	187
Other loans [Member]	'	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'	'
Nonaccrual loans, Total	1,198	'	3,052
Acquired loans [Member]	'	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'	'
Nonaccrual loans, Total	$7,229	'	$2,244

Loans_and_Allowance_for_Loan_L4

Loans and Allowance for Loan Losses - Age Analysis of Past Due Loans Segregated by Class of Loans (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
In Thousands, unless otherwise specified
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'	'
30-89 Days Past Due	$18,670	'	$15,970
90 Days and Greater	8,368	'	4,945
Total Past Due Loans	27,038	'	20,915
Current Loans	3,515,232	'	3,199,052
Total Loans	3,542,270	3,387,146	3,219,967
Accruing Loans 90 Days or More Past Due	910	1,179	542
Non-residential real estate owner occupied [Member]	'	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'	'
30-89 Days Past Due	518	'	1,230
90 Days and Greater	298	'	112
Total Past Due Loans	816	'	1,342
Current Loans	457,978	'	452,461
Total Loans	458,794	'	453,803
Accruing Loans 90 Days or More Past Due	96	'	18
Non-residential real estate other [Member]	'	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'	'
30-89 Days Past Due	4,978	'	2,063
90 Days and Greater	935	'	1,833
Total Past Due Loans	5,913	'	3,896
Current Loans	873,592	'	786,343
Total Loans	879,505	'	790,239
Accruing Loans 90 Days or More Past Due	'	'	'
Residential real estate permanent mortgage [Member]	'	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'	'
30-89 Days Past Due	1,867	'	2,351
90 Days and Greater	458	'	460
Total Past Due Loans	2,325	'	2,811
Current Loans	270,879	'	245,945
Total Loans	273,204	'	248,756
Accruing Loans 90 Days or More Past Due	76	'	163
Residential real estate all other [Member]	'	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'	'
30-89 Days Past Due	1,274	'	2,087
90 Days and Greater	543	'	408
Total Past Due Loans	1,817	'	2,495
Current Loans	565,930	'	522,542
Total Loans	567,747	'	525,037
Accruing Loans 90 Days or More Past Due	86	'	105
Non-consumer non-real estate [Member]	'	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'	'
30-89 Days Past Due	2,749	'	2,100
90 Days and Greater	929	'	214
Total Past Due Loans	3,678	'	2,314
Current Loans	824,361	'	748,287
Total Loans	828,039	'	750,601
Accruing Loans 90 Days or More Past Due	18	'	74
Consumer non-real estate [Member]	'	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'	'
30-89 Days Past Due	2,151	'	1,994
90 Days and Greater	260	'	184
Total Past Due Loans	2,411	'	2,178
Current Loans	223,551	'	209,142
Total Loans	225,962	'	211,320
Accruing Loans 90 Days or More Past Due	218	'	126
Other loans [Member]	'	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'	'
30-89 Days Past Due	2,080	'	2,152
90 Days and Greater	337	'	1,406
Total Past Due Loans	2,417	'	3,558
Current Loans	145,794	'	140,468
Total Loans	148,211	'	144,026
Accruing Loans 90 Days or More Past Due	'	'	'
Acquired loans [Member]	'	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'	'
30-89 Days Past Due	3,053	'	1,993
90 Days and Greater	4,608	'	328
Total Past Due Loans	7,661	'	2,321
Current Loans	153,147	'	93,864
Total Loans	160,808	'	96,185
Accruing Loans 90 Days or More Past Due	$416	'	$56

Loans_and_Allowance_for_Loan_L5

Loans and Allowance for Loan Losses - Impaired Loans Segregated by Class of Loans (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Unpaid Principal Balance	$51,195	$50,415
Recorded Investment with Allowance	41,833	45,230
Related Allowance	3,026	4,378
Average Recorded Investment	38,853	45,859
Non-residential real estate owner occupied [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Unpaid Principal Balance	688	580
Recorded Investment with Allowance	601	517
Related Allowance	29	19
Average Recorded Investment	642	732
Non-residential real estate other [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Unpaid Principal Balance	24,355	27,369
Recorded Investment with Allowance	22,680	25,900
Related Allowance	1,734	2,166
Average Recorded Investment	22,915	26,082
Residential real estate permanent mortgage [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Unpaid Principal Balance	1,068	1,448
Recorded Investment with Allowance	836	1,226
Related Allowance	88	61
Average Recorded Investment	918	1,007
Residential real estate all other [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Unpaid Principal Balance	1,318	4,631
Recorded Investment with Allowance	1,139	4,246
Related Allowance	218	1,276
Average Recorded Investment	1,335	3,840
Non-consumer non-real estate [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Unpaid Principal Balance	1,824	1,899
Recorded Investment with Allowance	1,491	1,565
Related Allowance	427	452
Average Recorded Investment	1,449	2,249
Consumer non-real estate [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Unpaid Principal Balance	548	441
Recorded Investment with Allowance	527	421
Related Allowance	134	96
Average Recorded Investment	572	408
Other loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Unpaid Principal Balance	1,215	3,736
Recorded Investment with Allowance	1,198	3,094
Related Allowance	207	267
Average Recorded Investment	1,278	2,648
Acquired loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Unpaid Principal Balance	20,179	10,311
Recorded Investment with Allowance	13,361	8,261
Related Allowance	189	41
Average Recorded Investment	$9,744	$8,893

Loans_and_Allowance_for_Loan_L6

Loans and Allowance for Loan Losses - Internal Loan Grading by Class of Loans (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
In Thousands, unless otherwise specified
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	$3,542,270	$3,387,146	$3,219,967
Non-residential real estate owner occupied [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	458,794	'	453,803
Non-residential real estate other [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	879,505	'	790,239
Residential real estate permanent mortgage [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	273,204	'	248,756
Residential real estate all other [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	567,747	'	525,037
Non-consumer non-real estate [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	828,039	'	750,601
Consumer non-real estate [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	225,962	'	211,320
Other loans [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	148,211	'	144,026
Acquired loans [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	160,808	'	96,185
Grade 1 [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	2,943,976	'	2,773,325
Grade 1 [Member] | Non-residential real estate owner occupied [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	381,290	'	393,152
Grade 1 [Member] | Non-residential real estate other [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	724,181	'	649,917
Grade 1 [Member] | Residential real estate permanent mortgage [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	240,653	'	208,732
Grade 1 [Member] | Residential real estate all other [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	474,152	'	461,620
Grade 1 [Member] | Non-consumer non-real estate [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	673,757	'	647,162
Grade 1 [Member] | Consumer non-real estate [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	212,492	'	198,107
Grade 1 [Member] | Other loans [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	144,870	'	139,696
Grade 1 [Member] | Acquired loans [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	92,581	'	74,939
Grade 2 [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	520,907	'	375,201
Grade 2 [Member] | Non-residential real estate owner occupied [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	70,949	'	55,109
Grade 2 [Member] | Non-residential real estate other [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	129,390	'	110,186
Grade 2 [Member] | Residential real estate permanent mortgage [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	25,074	'	33,463
Grade 2 [Member] | Residential real estate all other [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	86,033	'	51,181
Grade 2 [Member] | Non-consumer non-real estate [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	147,625	'	97,110
Grade 2 [Member] | Consumer non-real estate [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	11,388	'	10,912
Grade 2 [Member] | Other loans [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	2,375	'	2,304
Grade 2 [Member] | Acquired loans [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	48,073	'	14,936
Grade 3 [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	59,144	'	51,969
Grade 3 [Member] | Non-residential real estate owner occupied [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	6,052	'	5,142
Grade 3 [Member] | Non-residential real estate other [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	20,155	'	20,852
Grade 3 [Member] | Residential real estate permanent mortgage [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	6,610	'	5,730
Grade 3 [Member] | Residential real estate all other [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	6,495	'	8,410
Grade 3 [Member] | Non-consumer non-real estate [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	5,350	'	4,800
Grade 3 [Member] | Consumer non-real estate [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	1,655	'	1,923
Grade 3 [Member] | Other loans [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	736	'	1,103
Grade 3 [Member] | Acquired loans [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	12,091	'	4,009
Grade 4 [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	18,097	'	19,468
Grade 4 [Member] | Non-residential real estate owner occupied [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	503	'	400
Grade 4 [Member] | Non-residential real estate other [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	5,779	'	9,284
Grade 4 [Member] | Residential real estate permanent mortgage [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	867	'	831
Grade 4 [Member] | Residential real estate all other [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	1,067	'	3,826
Grade 4 [Member] | Non-consumer non-real estate [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	1,307	'	1,529
Grade 4 [Member] | Consumer non-real estate [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	427	'	374
Grade 4 [Member] | Other loans [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	230	'	923
Grade 4 [Member] | Acquired loans [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	7,917	'	2,301
Grade 5 [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	146	'	4
Grade 5 [Member] | Non-residential real estate owner occupied [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	'	'	'
Grade 5 [Member] | Non-residential real estate other [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	'	'	'
Grade 5 [Member] | Residential real estate permanent mortgage [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	'	'	'
Grade 5 [Member] | Residential real estate all other [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	'	'	'
Grade 5 [Member] | Non-consumer non-real estate [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	'	'	'
Grade 5 [Member] | Consumer non-real estate [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	'	'	4
Grade 5 [Member] | Other loans [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	'	'	'
Grade 5 [Member] | Acquired loans [Member]	'	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'	'
Total loans	$146	'	'

Loans_and_Allowance_for_Loan_L7

Loans and Allowance for Loan Losses - Activity in All by Class of Loans (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'
Balance at beginning of period	$39,034	$38,725
Charge- offs	-474	-533
Recoveries	146	172
Net charge- offs	-328	-361
Provisions charged to operations	1,218	300
Balance at end of period	39,924	38,664
Non-residential real estate owner occupied [Member]	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'
Balance at beginning of period	4,827	5,104
Charge- offs	-4	'
Recoveries	31	15
Net charge- offs	27	15
Provisions charged to operations	158	-253
Balance at end of period	5,012	4,866
Non-residential real estate other [Member]	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'
Balance at beginning of period	11,026	9,865
Charge- offs	'	-18
Recoveries	3	4
Net charge- offs	3	-14
Provisions charged to operations	-344	614
Balance at end of period	10,685	10,465
Residential real estate permanent mortgage [Member]	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'
Balance at beginning of period	2,825	2,781
Charge- offs	-130	-56
Recoveries	10	11
Net charge- offs	-120	-45
Provisions charged to operations	532	20
Balance at end of period	3,237	2,756
Residential real estate all other [Member]	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'
Balance at beginning of period	6,708	7,034
Charge- offs	-49	-95
Recoveries	4	2
Net charge- offs	-45	-93
Provisions charged to operations	-178	224
Balance at end of period	6,485	7,165
Non-consumer non-real estate [Member]	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'
Balance at beginning of period	8,977	9,385
Charge- offs	-70	-36
Recoveries	14	31
Net charge- offs	-56	-5
Provisions charged to operations	782	-398
Balance at end of period	9,703	8,982
Consumer non-real estate [Member]	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'
Balance at beginning of period	2,556	2,451
Charge- offs	-140	-140
Recoveries	62	76
Net charge- offs	-78	-64
Provisions charged to operations	95	-3
Balance at end of period	2,573	2,384
Other loans [Member]	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'
Balance at beginning of period	1,991	1,885
Charge- offs	-64	-139
Recoveries	17	'
Net charge- offs	-47	-139
Provisions charged to operations	128	76
Balance at end of period	2,072	1,822
Acquired loans [Member]	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'
Balance at beginning of period	124	220
Charge- offs	-17	-49
Recoveries	5	33
Net charge- offs	-12	-16
Provisions charged to operations	45	20
Balance at end of period	$157	$224

Loans_and_Allowance_for_Loan_L8

Loans and Allowance for Loan Losses - Allowance for Loan Losses Outstanding by Impairment Methodology (Detail) (USD $)	Mar. 31, 2014	Mar. 31, 2013
In Thousands, unless otherwise specified
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Individually evaluated for impairment	$5,375	$6,517
Collectively evaluated for impairment	34,549	32,147
Non-residential real estate owner occupied [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Individually evaluated for impairment	361	210
Collectively evaluated for impairment	4,651	4,656
Non-residential real estate other [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Individually evaluated for impairment	1,929	2,484
Collectively evaluated for impairment	8,756	7,981
Residential real estate permanent mortgage [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Individually evaluated for impairment	588	224
Collectively evaluated for impairment	2,649	2,532
Residential real estate all other [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Individually evaluated for impairment	733	1,899
Collectively evaluated for impairment	5,752	5,266
Non-consumer non-real estate [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Individually evaluated for impairment	1,133	1,211
Collectively evaluated for impairment	8,570	7,771
Consumer non-real estate [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Individually evaluated for impairment	389	290
Collectively evaluated for impairment	2,184	2,094
Other loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Individually evaluated for impairment	242	199
Collectively evaluated for impairment	1,830	1,623
Acquired loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Individually evaluated for impairment	'	'
Collectively evaluated for impairment	$157	$224

Loans_and_Allowance_for_Loan_L9

Loans and Allowance for Loan Losses - Loans Outstanding by Impairment Methodology (Detail) (USD $)	Mar. 31, 2014	Mar. 31, 2013
In Thousands, unless otherwise specified
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Individually evaluated for impairment	$56,575	$63,351
Collectively evaluated for impairment	3,465,541	3,150,306
Loans acquired with deteriorated credit quality	20,154	6,310
Non-residential real estate owner occupied [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Individually evaluated for impairment	6,555	5,542
Collectively evaluated for impairment	452,239	448,261
Loans acquired with deteriorated credit quality	'	'
Non-residential real estate other [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Individually evaluated for impairment	25,934	30,136
Collectively evaluated for impairment	853,571	760,103
Loans acquired with deteriorated credit quality	'	'
Residential real estate permanent mortgage [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Individually evaluated for impairment	7,477	6,561
Collectively evaluated for impairment	265,727	242,195
Loans acquired with deteriorated credit quality	'	'
Residential real estate all other [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Individually evaluated for impairment	7,562	12,236
Collectively evaluated for impairment	560,185	512,801
Loans acquired with deteriorated credit quality	'	'
Non-consumer non-real estate [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Individually evaluated for impairment	6,657	6,329
Collectively evaluated for impairment	821,382	744,272
Loans acquired with deteriorated credit quality	'	'
Consumer non-real estate [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Individually evaluated for impairment	2,082	2,301
Collectively evaluated for impairment	223,880	209,019
Loans acquired with deteriorated credit quality	'	'
Other loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Individually evaluated for impairment	308	246
Collectively evaluated for impairment	147,903	143,780
Loans acquired with deteriorated credit quality	'	'
Acquired loans [Member]	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'
Individually evaluated for impairment	'	'
Collectively evaluated for impairment	140,654	89,875
Loans acquired with deteriorated credit quality	$20,154	$6,310

Recovered_Sheet4

Loans and Allowance for Loan Losses - Transfers from Loans to Other Real Estate Owned and Repossessed Assets (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Financing Receivable Allowance For Credit Loss Additional Information Transfer From Loans To Other Real Estate Owned And Repossessed Assets [Abstract]	'	'
Other real estate owned	$66	$436
Repossessed assets	327	209
Total	$393	$645

Intangible_Assets_Summary_of_I

Intangible Assets - Summary of Intangible Assets (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
In Thousands, unless otherwise specified
Finite-Lived Intangible Assets [Line Items]	'	'	'
Gross Carrying Amount	$19,076	'	'
Accumulated Amortization	-7,527	'	'
Net Carrying Amount	11,549	10,273	11,595
Core deposit intangibles [Member]	'	'	'
Finite-Lived Intangible Assets [Line Items]	'	'	'
Gross Carrying Amount	12,681	'	'
Accumulated Amortization	-4,938	'	'
Net Carrying Amount	7,743	'	'
Customer relationship intangibles [Member]	'	'	'
Finite-Lived Intangible Assets [Line Items]	'	'	'
Gross Carrying Amount	5,699	'	'
Accumulated Amortization	-2,428	'	'
Net Carrying Amount	3,271	'	'
Mortgage servicing intangibles [Member]	'	'	'
Finite-Lived Intangible Assets [Line Items]	'	'	'
Gross Carrying Amount	696	'	'
Accumulated Amortization	-161	'	'
Net Carrying Amount	$535	'	'

Intangible_Assets_Summary_of_G

Intangible Assets - Summary of Goodwill By Business Segment (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Goodwill [Line Items]	'	'
Balance at beginning of period	$44,545	$44,545
Acquisitions	573	'
Balance at end of period	45,118	44,545
Metropolitan Banks [Member]	'	'
Goodwill [Line Items]	'	'
Balance at beginning of period	8,079	'
Acquisitions	'	'
Balance at end of period	8,079	'
Community Banks [Member]	'	'
Goodwill [Line Items]	'	'
Balance at beginning of period	30,552	'
Acquisitions	573	'
Balance at end of period	31,125	'
Other Financial Services [Member]	'	'
Goodwill [Line Items]	'	'
Balance at beginning of period	5,464	'
Acquisitions	'	'
Balance at end of period	5,464	'
Executive, Operations & Support [Member]	'	'
Goodwill [Line Items]	'	'
Balance at beginning of period	450	'
Acquisitions	'	'
Balance at end of period	$450	'

StockBased_Compensation_Additi

Stock-Based Compensation - Additional Information (Detail)	3 Months Ended				3 Months Ended
	Mar. 31, 2014	Mar. 31, 2014	31-May-13	Mar. 31, 2014	Mar. 31, 2014	31-May-09	Mar. 31, 2014
		Incentive Stock Option Plan [Member]	Incentive Stock Option Plan [Member]	Incentive Stock Option Plan [Member]	Non Employee Directors Stock Option Plan [Member]	Non Employee Directors Stock Option Plan [Member]	Non Employee Directors Stock Option Plan [Member]
				Minimum [Member]			Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'	'
Number of shares to be issued under incentive stock option plan	'	'	3,000,000	'	'	205,000	'
Shares for future grants	'	145,860	'	'	5,000	'	'
Option exercisable rate	'	25.00%	'	'	25.00%	'	'
Option exercisable period	'	'4 years	'	'	'1 year	'	'
Options expire period	'	'15 years	'	'	'15 years	'	'
Share based compensation options exercisable period	'	'2020	'	'	'2017	'	'
Stock price percentage to fair value at grant date	'	'	'	100.00%	'	'	100.00%
Vesting period in years	'7 years	'4 years	'	'	'4 years	'	'
Options vest and exercisable Description	'	'The options vest and are exercisable beginning four years from the date of grant at the rate of 25% per year for four years. Options expire at the end of fifteen years from the date of grant.	'	'	'The options vest and are exercisable beginning one year from the date of grant at the rate of 25% per year for four years.	'	'
Stock option plan termination date	'	31-Dec-14	'	'	'	'	'
Number of options granted for non-employee director	10,000	'	'	'	'	'	'

StockBased_Compensation_Summar

Stock-Based Compensation - Summary of Activity Under Stock Option Plan (Detail) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Outstanding at beginning period - Options	1,158,317
Options granted	'
Options exercised	-28,750
Options canceled, forfeited or expired - Options	'
Outstanding at ending period - Options	1,129,567
Exercisable at ending period - Options	538,667
Outstanding at beginning period - Wgtd. Avg. Exercise Price	$34.45
Options granted - Wgtd. Avg. Exercise Price	'
Options exercised - Wgtd. Avg. Exercise Price	$30.10
Options cancelled, forfeited, or expired - Wgtd. Avg. Exercise Price	'
Outstanding at ending period - Wgtd. Avg. Exercise Price	$34.56
Exercisable at ending period - Wgtd. Avg. Exercise Price	$28.01
Outstanding at ending period - Wgtd. Avg. Remaining Contractual Term, years	'8 years 7 months 17 days
Exercisable at ending period - Wgtd. Avg. Remaining Contractual Term, years	'6 years 2 months 9 days
Outstanding at ending period - Aggregate Intrinsic Value	$24,931
Exercisable at ending period - Aggregate Intrinsic Value	$15,415

StockBased_Compensation_Option

Stock-Based Compensation - Options Granted and Options Exercised Under Stock Option Plan (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Share Based Compensation Arrangement By Share Based Payment Award Options Additional Disclosures [Abstract]	'	'
Weighted average grant-date fair value per share of options granted	'	'
Total intrinsic value of options exercised	$745	$206
Cash received from options exercised	865	142
Tax benefit realized from options exercised	$288	$80

StockBased_Compensation_StockB

Stock-Based Compensation - Stock-Based Employee Compensation Expense (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Labor And Related Expense [Abstract]	'	'
Stock-based compensation expense	$347	$374
Tax benefit	134	145
Stock-based compensation expense, net of tax	$213	$229

StockBased_Compensation_Remain

Stock-Based Compensation - Remaining Fair Value of Stock Options (Detail) (USD $)	Mar. 31, 2014
In Thousands, unless otherwise specified
Remaining Fair Value Of Stock Options [Abstract]	'
Fair value of stock options	$4,778

Stockholders_Equity_Summary_of

Stockholders' Equity - Summary of Shares Repurchased Under Stock Purchase Program (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Summary Of Shares Repurchased Under Stock Purchase Program [Abstract]	'	'
Number of shares repurchased	'	23,050
Average price of shares repurchased	'	$40.92
Shares remaining to be repurchased	194,723	211,914

Stockholders_Equity_Required_C

Stockholders' Equity - Required Capital Amounts and Company's Respective Ratios (Detail) (USD $)	Mar. 31, 2014
In Thousands, unless otherwise specified
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]	'
Tier 1 Risk Based Capital Required To Be Well Capitalized To Risk Weighted Assets Ratio	6.00%
Tier 1 Capital Required To Be Well Capitalized To Average assets Ratio	5.00%
Parent Company [Member]	'
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]	'
Total Capital To Risk Weighted Assets Actual Amount	573,963
Total Capital To Risk Weighted Assets Actual Ratio	14.52%
Capital Required For Capital Adequacy Amount	316,297
Capital Required For Capital Adequacy to Risk Weighted Assets Ratio	8.00%
Tier 1 Risk Based Capital Amount	534,039
Tier 1 Risk Based Capital To Risk Weighted Assets Ratio	13.51%
Tier 1 Risk Based Capital Required For Capital Adequacy Amount	158,148
Tier 1 Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets Ratio	4.00%
Tier 1 Capital Amount	534,039
Tier 1 Capital To Average Assets Ratio	8.45%
Tier 1 Capital Required For Capital Adequacy Amount	191,252
Tier 1 Capital Required For Capital Adequacy To Average Assets Ratio	3.00%
BancFirst [Member]	'
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]	'
Total Capital To Risk Weighted Assets Actual Amount	537,600
Total Capital To Risk Weighted Assets Actual Ratio	13.62%
Capital Required For Capital Adequacy Amount	315,685
Capital Required For Capital Adequacy to Risk Weighted Assets Ratio	8.00%
Capital Required To Be Well Capitalized Amount	394,606
Capital Required To Be Well Capitalized To Risk Weighted Assets Ratio	10.00%
Tier 1 Risk Based Capital Amount	497,676
Tier 1 Risk Based Capital To Risk Weighted Assets Ratio	12.61%
Tier 1 Risk Based Capital Required For Capital Adequacy Amount	157,842
Tier 1 Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets Ratio	4.00%
Tier 1 Risk Based Capital Required To Be well Capitalized Amount	236,763
Tier 1 Risk Based Capital Required To Be Well Capitalized To Risk Weighted Assets Ratio	6.00%
Tier 1 Capital Amount	497,676
Tier 1 Capital To Average Assets Ratio	7.89%
Tier 1 Capital Required For Capital Adequacy Amount	190,650
Tier 1 Capital Required For Capital Adequacy To Average Assets Ratio	3.00%
Tier 1 Capital Required To Be Well Capitalized Amount	317,750
Tier 1 Capital Required To Be Well Capitalized To Average assets Ratio	5.00%

Stockholders_Equity_Additional

Stockholders' Equity - Additional Information (Detail) (USD $)	3 Months Ended
In Billions, unless otherwise specified	Mar. 31, 2014
Stockholders Equity [Line Items]	'
Minimum Tier 1 Ratio to be well capitalized	6.00%
Minimum combined Tier 1 and Tier 2 Ratio to be well capitalized	10.00%
Minimum Leverage Ratio to be well capitalized	5.00%
Maximum [Member]	'
Stockholders Equity [Line Items]	'
Quantitative limit for trust preferred securities to be included in tier 1 capital	10
2015 [Member]	'
Stockholders Equity [Line Items]	'
Implementation of the deductions and other adjustments to CET1	'4 years
Implementation of the deductions and other adjustments to CET1, Percentage	40.00%
2015 [Member] | Minimum [Member]	'
Stockholders Equity [Line Items]	'
Minimum ratio of CET1 to risk-weighted assets	4.50%
Tier 1 capital to risk-weighted assets	6.00%
Total capital to risk weighted assets	8.00%
Minimum leverage ratio	4.00%
2016 [Member]	'
Stockholders Equity [Line Items]	'
Implementation of the capital conservation buffer, Percentage	0.63%
Capital conservation buffer implementation phase-out period	'4 years
2019 [Member]	'
Stockholders Equity [Line Items]	'
Capital Conservation Buffer Maximum Level	2.50%
After 2015 [Member]	'
Stockholders Equity [Line Items]	'
Implementation of the deductions and other adjustments to CET1, Additional Percentage	20.00%

Net_Income_Per_Common_Share_Ba

Net Income Per Common Share - Basic and Diluted Net Income Per Common Share (Detail) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Earnings Per Share Reconciliation [Abstract]	'	'
Income available to common stockholders	$14,657	$13,372
Income available to common stockholders plus assumed exercises of stock options	$14,657	$13,372
Income available to common stockholders - Shares	15,342,486	15,238,701
Effect of stock options - Shares	318,434	243,816
Income available to common stockholders plus assumed exercises of stock options - Shares	15,660,920	15,482,517
Income available to common stockholders - Per Share Amount	$0.96	$0.88
Income available to common stockholders plus assumed exercises of stock options - Per Share Amount	$0.94	$0.86

Net_Income_Per_Common_Share_Av

Net Income Per Common Share - Average Exercise Prices of Options Excluded from Computation of Diluted Net Income Per Common Share (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Abstract]	'	'
Shares	65,000	534,000
Average Exercise Price	$54.01	$39.44

Fair_Value_Measurements_Additi

Fair Value Measurements - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Debt Instrument Fair Value Disclosure [Abstract]	'	'
Loan held for sale selling period	'30 days	'
Transfer of securities between levels of fair value hierarchy	$0	$0
Amount of non-financial assets (liabilities)	0	0
Non-financial assets or liabilities for which no impairment was provided	$0	$0

Fair_Value_Measurements_Fair_V

Fair Value Measurements - Fair Value of Financial Assets and Liabilities Measured on Recurring Basis (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Securities available for sale	$575,749	'	'
Derivative assets	3,072	'	3,424
Derivative liabilities	1,667	'	1,658
Loans held for sale	5,231	6,469	7,211
Mortgage servicing intangibles	535	'	709
U.S. Treasury [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Securities available for sale	128,740	'	20,304
U.S. federal agencies [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Securities available for sale	346,793	'	442,075
States and political subdivisions [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Securities available for sale	54,971	'	55,493
Other securities [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Securities available for sale	15,381	'	13,545
Mortgage-backed securities [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Securities available for sale	29,864	'	17,974
Level 1 Inputs [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative assets	'	'	'
Derivative liabilities	'	'	'
Loans held for sale	'	'	'
Mortgage servicing intangibles	'	'	'
Level 1 Inputs [Member] | U.S. Treasury [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Securities available for sale	128,740	'	20,304
Level 1 Inputs [Member] | U.S. federal agencies [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Securities available for sale	'	'	'
Level 1 Inputs [Member] | States and political subdivisions [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Securities available for sale	'	'	'
Level 1 Inputs [Member] | Other securities [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Securities available for sale	'	'	'
Level 1 Inputs [Member] | Mortgage-backed securities [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Securities available for sale	'	'	'
Level 2 Inputs [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative assets	3,072	'	3,424
Derivative liabilities	1,667	'	1,658
Loans held for sale	5,231	'	7,211
Mortgage servicing intangibles	'	'	'
Level 2 Inputs [Member] | U.S. Treasury [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Securities available for sale	'	'	'
Level 2 Inputs [Member] | U.S. federal agencies [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Securities available for sale	346,793	'	442,075
Level 2 Inputs [Member] | States and political subdivisions [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Securities available for sale	54,971	'	55,493
Level 2 Inputs [Member] | Other securities [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Securities available for sale	3,482	'	3,421
Level 2 Inputs [Member] | Mortgage-backed securities [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Securities available for sale	12,277	'	17,974
Level 3 Inputs [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative assets	'	'	'
Derivative liabilities	'	'	'
Loans held for sale	'	'	'
Mortgage servicing intangibles	535	'	709
Level 3 Inputs [Member] | U.S. Treasury [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Securities available for sale	'	'	'
Level 3 Inputs [Member] | U.S. federal agencies [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Securities available for sale	'	'	'
Level 3 Inputs [Member] | States and political subdivisions [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Securities available for sale	'	'	'
Level 3 Inputs [Member] | Other securities [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Securities available for sale	11,899	'	10,124
Level 3 Inputs [Member] | Mortgage-backed securities [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Securities available for sale	$17,587	'	'

Fair_Value_Measurements_Change

Fair Value Measurements - Changes in Level 3 Assets Measured at Estimated Fair Value on Recurring Basis (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]	'	'
Balance at the beginning of the year	$32,002	$10,779
Purchases, issuances and settlements	-1,847	116
Sales	-499	-15
Gains included in earnings	417	-30
Total unrealized losses	-52	-17
Balance at the end of the period	$30,021	$10,833

Fair_Value_Measurements_Assets

Fair Value Measurements - Assets Measured at Fair Value on Nonrecurring Basis (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Impaired loans (less specific allowance) [Member]	'	'
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'	'
Total Fair Value	$38,807	$40,852
Gains (Losses)	'	'
Foreclosed Assets [Member]	'	'
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'	'
Total Fair Value	262	326
Gains (Losses)	-12	13
Other real estate owned [Member]	'	'
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'	'
Total Fair Value	7,328	9,098
Gains (Losses)	-517	-87
Level 1 Inputs [Member] | Impaired loans (less specific allowance) [Member]	'	'
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'	'
Total Fair Value	'	'
Level 1 Inputs [Member] | Foreclosed Assets [Member]	'	'
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'	'
Total Fair Value	'	'
Level 1 Inputs [Member] | Other real estate owned [Member]	'	'
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'	'
Total Fair Value	'	'
Level 2 Inputs [Member] | Impaired loans (less specific allowance) [Member]	'	'
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'	'
Total Fair Value	'	'
Level 2 Inputs [Member] | Foreclosed Assets [Member]	'	'
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'	'
Total Fair Value	'	'
Level 2 Inputs [Member] | Other real estate owned [Member]	'	'
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'	'
Total Fair Value	'	'
Level 3 Inputs [Member] | Impaired loans (less specific allowance) [Member]	'	'
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'	'
Total Fair Value	38,807	40,852
Level 3 Inputs [Member] | Foreclosed Assets [Member]	'	'
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'	'
Total Fair Value	262	326
Level 3 Inputs [Member] | Other real estate owned [Member]	'	'
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]	'	'
Total Fair Value	$7,328	$9,098

Fair_Value_Measurements_Estima

Fair Value Measurements - Estimated Fair Values of Company's Financial Instruments (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
FINANCIAL ASSETS	'	'	'	'
Cash and cash equivalents	$1,963,106	$1,857,535	$1,716,052	$1,945,148
Securities held for investment	11,269	'	'	'
Loans, net	3,502,346	3,348,112	3,181,303	'
FINANCIAL LIABILITIES	'	'	'	'
Deposits	5,737,850	5,419,519	5,174,512	'
Short-term borrowings	8,603	4,590	4,891	'
Long-term borrowings	2,000	6,938	11,040	'
Junior subordinated debentures	26,804	26,804	26,804	'
Carrying Amount [Member]	'	'	'	'
OFF-BALANCE SHEET FINANCIAL INSTRUMENTS	'	'	'	'
Loan commitments	'	'	'	'
Letters of credit	'	'	'	'
Carrying Amount [Member] | Level 2 Inputs [Member]	'	'	'	'
FINANCIAL ASSETS	'	'	'	'
Cash and cash equivalents	1,966,106	'	1,716,052	'
Securities held for investment	11,269	'	16,099	'
FINANCIAL LIABILITIES	'	'	'	'
Deposits	5,737,850	'	5,174,512	'
Short-term borrowings	8,603	'	4,891	'
Long-term borrowings	2,000	'	11,040	'
Junior subordinated debentures	26,804	'	26,804	'
Carrying Amount [Member] | Level 3 Inputs [Member]	'	'	'	'
FINANCIAL ASSETS	'	'	'	'
Loans, net	3,502,346	'	3,181,303	'
Fair Value [Member]	'	'	'	'
OFF-BALANCE SHEET FINANCIAL INSTRUMENTS	'	'	'	'
Loan commitments	1,712	'	1,556	'
Letters of credit	459	'	469	'
Fair Value [Member] | Level 2 Inputs [Member]	'	'	'	'
FINANCIAL ASSETS	'	'	'	'
Cash and cash equivalents	1,966,106	'	1,716,052	'
Securities held for investment	11,351	'	16,317	'
FINANCIAL LIABILITIES	'	'	'	'
Deposits	5,538,503	'	5,200,273	'
Short-term borrowings	8,603	'	4,891	'
Long-term borrowings	1,997	'	11,010	'
Junior subordinated debentures	28,948	'	31,093	'
Fair Value [Member] | Level 3 Inputs [Member]	'	'	'	'
FINANCIAL ASSETS	'	'	'	'
Loans, net	$3,424,944	'	$3,240,479	'

Recovered_Sheet5

Derivative Financial Instruments - Notional Amounts and Estimated Fair Values of Outstanding Derivative Positions (Detail) (USD $)	Mar. 31, 2014
In Thousands, unless otherwise specified
Oil [Member]	'
Derivatives, Fair Value [Line Items]	'
Notional Units	'Barrels
Derivative assets, Notional Amount	$310
Derivative assets, Estimated Fair Value	981
Derivative liabilities, Notional Amount	-310
Derivative liabilities, Estimated Fair Value	-572
Natural Gas [Member]	'
Derivatives, Fair Value [Line Items]	'
Notional Units	'MMBTUs
Derivative assets, Notional Amount	2,731
Derivative assets, Estimated Fair Value	2,091
Derivative liabilities, Notional Amount	-2,731
Derivative liabilities, Estimated Fair Value	-1,095
Other Liabilities [Member]	'
Derivatives, Fair Value [Line Items]	'
Derivative liabilities, Notional Amount	'
Derivative liabilities, Estimated Fair Value	-1,667
Other Assets [Member]	'
Derivatives, Fair Value [Line Items]	'
Derivative assets, Notional Amount	'
Derivative assets, Estimated Fair Value	$3,072

Recovered_Sheet6

Derivative Financial Instruments - Recognized Derivative Income Included in Other Noninterest Income (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Derivative Gain Loss On Derivative Net [Abstract]	'	'
Derivative income	$149	$108

Derivative_Financial_Instrumen2

Derivative Financial Instruments - Summary of the Company's Net Credit Exposure Relating to Oil and Gas Swaps (Detail) (USD $)	Mar. 31, 2014
In Thousands, unless otherwise specified
Credit Risk Derivatives At Fair Value Net [Abstract]	'
Credit exposure	$2,974

Segment_Information_Additional

Segment Information - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2014
	Business_Unit
Segment Reporting [Abstract]	'
Number of principal business units	4

Segment_Information_Results_of

Segment Information - Results of Operations and Selected Financial Information (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Segment Reporting Information [Line Items]	'	'	'
Net interest income (expense)	$42,029	$40,256	'
Noninterest income	23,562	22,535	'
Income before taxes	20,537	20,547	'
Total Assets	6,375,041	5,773,926	6,038,974
Operating Segments [Member] | Metropolitan Banks [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net interest income (expense)	13,787	14,011	'
Noninterest income	3,413	3,190	'
Income before taxes	7,790	8,937	'
Total Assets	2,093,563	1,926,511	2,079,444
Operating Segments [Member] | Community Banks [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net interest income (expense)	27,241	25,144	'
Noninterest income	12,266	11,545	'
Income before taxes	15,077	14,077	'
Total Assets	3,973,407	3,627,011	3,764,429
Operating Segments [Member] | Other Financial Services [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net interest income (expense)	1,376	1,565	'
Noninterest income	7,056	6,902	'
Income before taxes	3,066	3,237	'
Total Assets	113,732	109,887	103,656
Operating Segments [Member] | Executive, Operations & Support [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net interest income (expense)	-375	-464	'
Noninterest income	15,955	14,749	'
Income before taxes	9,679	8,094	'
Total Assets	816,489	690,318	703,294
Eliminations [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net interest income (expense)	'	'	'
Noninterest income	-15,128	-13,851	'
Income before taxes	-15,075	-13,798	'
Total Assets	($622,150)	($579,801)	($611,849)