BancFirst (BANF) 10-Q 2 Aug 19 2019 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2019	Jul. 31, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Trading Symbol	BANF
Entity Registrant Name	BANCFIRST CORP /OK/
Entity Central Index Key	0000760498
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, $1.00 Par Value Per Share
Security Exchange Name	NASDAQ
Entity File Number	0-14384
Entity Incorporation, State or Country Code	OK
Entity Tax Identification Number	73-1221379
Entity Address, Address Line One	101 N. Broadway
Entity Address, City or Town	Oklahoma City
Entity Address, State or Province	OK
Entity Address, Postal Zip Code	73102-8405
City Area Code	(405)
Local Phone Number	270-1086
Document Quarterly Report	true
Document Transition Report	false
Entity Common Stock, Shares Outstanding		32,642,018

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
ASSETS
Cash and due from banks	$ 185,440	$ 228,431
Interest-bearing deposits with banks	1,518,998	1,195,824
Securities held for investment (fair value: $2,003 and $1,433, respectively)	1,997	1,428
Securities available for sale at fair value	423,157	770,704
Loans held for sale	10,899	8,174
Loans (net of unearned interest)	5,094,403	4,975,976
Allowance for loan losses	(55,108)	(51,389)
Loans, net of allowance for loan losses	5,039,295	4,924,587
Premises and equipment, net	180,506	174,362
Other real estate owned	6,787	6,690
Intangible assets, net	14,936	16,470
Goodwill	79,749	79,749
Accrued interest receivable and other assets	180,257	167,839
Total assets	7,642,021	7,574,258
Deposits:
Noninterest-bearing	2,634,582	2,613,876
Interest-bearing	3,979,031	3,991,619
Total deposits	6,613,613	6,605,495
Short-term borrowings	1,000	1,675
Accrued interest payable and other liabilities	44,224	37,495
Junior subordinated debentures	26,804	26,804
Total liabilities	6,685,641	6,671,469
Stockholders' equity:
Common stock, $1.00 par, 40,000,000 shares authorized; shares issued and outstanding: 32,639,588 and 32,603,926, respectively	32,640	32,604
Capital surplus	150,995	149,709
Retained earnings	769,090	722,615
Accumulated other comprehensive income (loss), net of income tax of $1,249 and $(731), respectively	3,655	(2,139)
Total stockholders' equity	956,380	902,789
Total liabilities and stockholders' equity	7,642,021	7,574,258
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 ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Securities, fair value	$ 2,003	$ 1,433
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	40,000,000	40,000,000
Common stock, shares issued	32,639,588	32,603,926
Common stock, shares outstanding	32,639,588	32,603,926
Accumulated other comprehensive income (loss), tax expense (benefit)	$ 1,249	$ (731)
Senior Preferred Stock [Member]
Preferred stock, par value	$ 1	$ 1
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Cumulative Preferred Stock [Member]
Preferred stock, par value	$ 5	$ 5
Preferred stock, shares authorized	900,000	900,000
Preferred stock, shares issued	0	0

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
INTEREST INCOME
Loans, including fees	$ 70,990	$ 65,604	$ 139,720	$ 128,523
Securities:
Taxable	3,855	1,956	8,190	3,854
Tax-exempt	118	162	244	333
Federal funds sold		95	2	199
Interest-bearing deposits with banks	8,135	7,325	15,883	13,107
Total interest income	83,098	75,142	164,039	146,016
INTEREST EXPENSE
Deposits	13,802	9,710	27,339	16,979
Short-term borrowings	12	8	22	43
Junior subordinated debentures	492	544	983	1,079
Total interest expense	14,306	10,262	28,344	18,101
Net interest income	68,792	64,880	135,695	127,915
Provision for loan losses	2,433	1,225	4,117	1,539
Net interest income after provision for loan losses	66,359	63,655	131,578	126,376
NONINTEREST INCOME
Securities transactions (includes no accumulated other comprehensive income reclassifications)	821	115	821	101
Income from sales of loans	868	802	1,566	1,453
Insurance commissions	4,420	3,927	9,685	9,126
Cash management	4,402	3,381	8,178	6,402
(Loss)/gain on sale of other assets	(7)	127	(11)	153
Other	1,209	1,152	2,635	2,597
Total noninterest income	34,077	30,437	66,078	60,547
NONINTEREST EXPENSE
Salaries and employee benefits	36,124	34,776	72,295	68,966
Occupancy, net	2,953	3,396	5,580	6,798
Depreciation	3,015	2,429	6,000	4,839
Amortization of intangible assets	758	759	1,517	1,492
Data processing services	1,262	1,195	2,742	2,398
Net expense/(income) from other real estate owned	97	19	(387)	45
Marketing and business promotion	1,919	1,649	4,180	4,001
Deposit insurance	544	640	1,077	1,259
Other	9,936	9,393	19,810	20,348
Total noninterest expense	56,608	54,256	112,814	110,146
Income before taxes	43,828	39,836	84,842	76,777
Income tax expense	9,661	9,250	18,838	16,571
Net income	$ 34,167	$ 30,586	$ 66,004	$ 60,206
NET INCOME PER COMMON SHARE
Basic	$ 1.04	$ 0.93	$ 2.02	$ 1.84
Diluted	$ 1.02	$ 0.91	$ 1.98	$ 1.80
OTHER COMPREHENSIVE GAIN/(LOSS)
Unrealized gains/(losses) on securities, net of tax of $(1,112), $179, $(1,980) and $653, respectively	$ 3,254	$ (541)	$ 5,794	$ (1,929)
Other comprehensive gains/(losses), net of tax of $(1,112), $179, $(1,980) and $653, respectively	3,254	(541)	5,794	(1,929)
Comprehensive income	37,421	30,045	71,798	58,277
Trust Revenue [Member]
NONINTEREST INCOME
Revenue	3,250	3,396	6,427	6,525
Service Charges on Deposits [Member]
NONINTEREST INCOME
Revenue	$ 19,114	$ 17,537	$ 36,777	$ 34,190

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Unaudited) (Parenthetical) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Securities transactions accumulated other comprehensive income reclassifications	$ 0	$ 0	$ 0	$ 0
Unrealized gains (losses) on securities, tax	(1,112,000)	179,000	(1,980,000)	653,000
Other comprehensive gains (losses), tax	$ (1,112,000)	$ 179,000	$ (1,980,000)	$ 653,000

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	COMMON STOCK [Member]	CAPITAL SURPLUS [Member]	RETAINED EARNINGS [Member]	ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) [Member]
Balance at beginning of period at Dec. 31, 2017		$ 31,895	$ 107,481	$ 638,580	$ (2,327)
Shares issued for stock options		103	1,620
Shares issued for acquisitions		733	38,765
Stock-based compensation arrangements			628
Net income	$ 60,206			60,206
Cumulative effect of change in accounting principle				(618)	618
Dividends on common stock				(13,743)
Net change	(1,929)				(1,929)
Balance at end of period at Jun. 30, 2018	862,012	32,731	148,494	684,425	(3,638)
Balance at beginning of period at Mar. 31, 2018		32,708	147,762	660,723	(3,097)
Shares issued for stock options		23	410
Stock-based compensation arrangements			322
Net income	30,586			30,586
Dividends on common stock				(6,884)
Net change	(541)				(541)
Balance at end of period at Jun. 30, 2018	862,012	32,731	148,494	684,425	(3,638)
Balance at beginning of period at Dec. 31, 2018	902,789	32,604	149,709	722,615	(2,139)
Shares issued for stock options		36	745
Stock-based compensation arrangements			541
Net income	66,004			66,004
Dividends on common stock				(19,529)
Net change	5,794				5,794
Balance at end of period at Jun. 30, 2019	956,380	32,640	150,995	769,090	3,655
Balance at beginning of period at Mar. 31, 2019		32,618	150,195	744,713	401
Shares issued for stock options		22	433
Stock-based compensation arrangements			367
Net income	34,167			34,167
Dividends on common stock				(9,790)
Net change	3,254				3,254
Balance at end of period at Jun. 30, 2019	$ 956,380	$ 32,640	$ 150,995	$ 769,090	$ 3,655

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity (Unaudited) (Parenthetical) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
RETAINED EARNINGS [Member]
Dividend on common stock	$ 0.30	$ 0.21	$ 0.60	$ 0.42

Consolidated Statements of Cash

Consolidated Statements of Cash Flow (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 66,004	$ 60,206
Adjustments to reconcile to net cash provided by operating activities:
Provision for loan losses	4,117	1,539
Depreciation and amortization	7,517	6,331
Net amortization of securities premiums and discounts	(3,650)	(77)
Realized securities gains	(821)	(101)
Gain on sales of loans	(1,566)	(1,453)
Cash receipts from the sale of loans originated for sale	98,587	95,713
Cash disbursements for loans originated for sale	(99,782)	(97,676)
Deferred income tax benefit	(893)	(604)
Gain on other assets	(455)	(156)
Increase in interest receivable	(2,064)	(2,618)
Increase in interest payable	461	575
Amortization of stock-based compensation arrangements	541	628
Excess tax benefit from stock-based compensation arrangements	(263)	(898)
Other, net	4,374	(2,847)
Net cash provided by operating activities	72,107	58,562
INVESTING ACTIVITIES
Net cash received from acquisitions, net of cash paid		6,248
Net decrease in federal funds sold		750
Purchases of held for investment securities	(1,010)	(225)
Purchases of available for sale securities		(60,604)
Proceeds from maturities, calls and paydowns of held for investment securities	440	509
Proceeds from maturities, calls and paydowns of available for sale securities	358,972	59,235
Proceeds from sales of available for sale securities		1,467
Purchase of equity securities	(2,649)	(1,709)
Proceeds from paydowns and sales of equity securities	1,892	1,080
Net change in loans	(121,426)	24,177
Purchases of premises, equipment and computer software	(12,907)	(16,631)
Other, net	(3,893)	400
Net cash provided by investing activities	219,419	14,697
FINANCING ACTIVITIES
Net change in deposits	8,118	(52,831)
Net (decrease)/increase in short-term borrowings	(675)	1,600
Issuance of common stock in connection with stock options, net	781	1,723
Cash dividends paid	(19,567)	(13,566)
Net cash used in financing activities	(11,343)	(63,074)
Net increase in cash, due from banks and interest-bearing deposits	280,183	10,185
Cash, due from banks and interest-bearing deposits at the beginning of the period	1,424,255	1,757,875
Cash, due from banks and interest-bearing deposits at the end of the period	1,704,438	1,768,060
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid during the period for interest	27,882	17,525
Cash paid during the period for income taxes	17,175	16,150
Noncash investing and financing activities:
Stock issued in acquisitions		39,498
Cash consideration for acquisitions		24,722
Fair value of assets acquired in acquisitions		377,320
Liabilities assumed in acquisitions		338,860
Unpaid common stock dividends declared	$ 9,788	$ 6,870

Description of Business and Sum

Description of Business and Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2019
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 States 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, 2018. Basis of Presentation The accompanying unaudited interim consolidated financial statements include the accounts of BancFirst Corporation, Council Oak Partners, LLC, BancFirst Insurance Services, Inc., BancFirst Risk & Insurance Company and BancFirst and its subsidiaries. The principal operating subsidiaries of BancFirst are Council Oak Investment Corporation, Council Oak Real Estate, Inc., BFTower, LLC and BancFirst Agency, Inc. All significant intercompany accounts and transactions have been eliminated. Assets held in a fiduciary or agency capacity are not assets of the Company and, accordingly, are not included in the unaudited interim consolidated financial statements. The accompanying unaudited interim consolidated financial statements and notes are presented in accordance with the instructions for Form 10-Q. The information contained in the financial statements and footnotes included in BancFirst Corporation’s Annual Report on Form 10-K for the year ended December 31, 2018, should be referred to in connection with these unaudited interim consolidated financial statements. Operating results for the interim periods disclosed herein are not necessarily indicative of the results that may be expected for a full year or any future period. The unaudited interim consolidated financial statements contained herein reflect all adjustments which are, in the opinion of management, necessary to provide a fair statement of the financial position and results of operations of the Company for the interim periods presented. All such adjustments are of a normal and recurring nature. There have been no significant changes in the accounting policies of the Company since December 31, 2018, the date of the most recent annual report. Reclassifications Certain items in prior financial statements have been reclassified to conform to the current presentation. Such reclassifications had no effect on previously reported net cash flows, stockholders’ equity or comprehensive income. Use of Estimates in the Preparation of Financial Statements The preparation of financial statements in conformity with accounting principles generally accepted in the United States inherently involves the use of estimates and assumptions that affect the amounts reported in the financial statements and the related disclosures. These estimates relate principally to the determination of the allowance for loan losses, income taxes, the fair value of financial instruments and the valuation of intangibles. Such estimates and assumptions may change over time and actual amounts realized may differ from those reported. Recent Accounting Pronouncements Standards Adopted During Current Period: In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-02, “Leases - (Topic 842)”, amended by ASU 2018-11, “Leases – (Topic 842)”: Targeted Improvements. This new guidance requires a lessee to recognize on the balance sheet the assets and liabilities for the rights and obligations created by leases with lease terms of more than twelve months and provide additional disclosures. The amendments were effective for annual periods, and interim reporting periods within those annual periods, beginning after December 15, 2018. The Company adopted this new standard on January 1, 2019, using a modified retrospective transition approach and recognized right-of-use lease assets and related lease liabilities totaling $4.3 million . Standards Not Yet Adopted: In August 2018, the FASB issued ASU No. 2018-13, “Fair Value Measurement (Topic 820).” ASU 2018-13 removes, modifies and adds disclosure requirements on fair value measurements. ASU 2018-13 will be effective for the Company on January 1, 2020. Early adoption is permitted. In addition, early adoption of any removed or modified disclosures and delayed adoption of the additional disclosures until the effective date is also permitted. The Company expects to adopt the standard in the first quarter of 2020. In June 2016, the FASB issued ASU No. 2016-13, “Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” ASU 2016-13 requires a financial asset measured at amortized cost basis to be presented at the net amount expected to be collected. The measurement of expected credit losses is based on relevant information about past events, including historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. ASU 2016-13 requires enhanced disclosures related to the significant estimates and judgements used in estimating credit losses, as well as the credit quality and underwriting standards of an organization’s portfolio. In addition, ASU 2016-13 amends the accounting for credit losses on available-for-sale debt securities and purchased financial assets with credit deterioration. ASU 2016-13 will be effective for the Company on January 1, 2020. The Company is currently evaluating the potential impact of ASU 2016-13 on its financial statements. In that regard, the Company has formed a task force under the direction of its Chief Financial Officer. In preparation, the Company has developed new credit estimation models, processes and controls. Internal validation of the model is underway and expected to be completed during the third quarter of 2019. The Company has performed test runs of the new processes and controls and will begin full parallel runs next quarter. The adoption of ASU 2016-13 could result in an increase or decrease in the allowance for loan losses as a result of changing from an “incurred loss” model, which encompasses allowances for current known and inherent losses within the portfolio, to an “expected loss” model, which encompasses allowances for losses expected to be incurred over the life of the portfolio. Furthermore, ASU 2016-13 will necessitate that the Company establish an allowance for expected credit losses for certain debt securities and other financial assets. While the Company is currently unable to reasonably estimate the impact of adopting ASU 2016-13, we expect that the impact of adoption will be significantly influenced by the composition, characteristics and quality of our loan and securities portfolios as well as the prevailing economic conditions and forecasts as of the adoption date. The Company expects to adopt the standard in the first quarter of 2020.

Recent Developments, Including

Recent Developments, Including Mergers and Acquisitions	6 Months Ended
	Jun. 30, 2019
Recent Developments Including Mergers And Acquisitions [Abstract]
Recent Developments, Including Mergers and Acquisitions	(2) RECENT DEVELOPMENTS, INCLUDING MERGERS AND ACQUISITIONS On April 23, 2019, BancFirst Corporation entered into an agreement to acquire Pegasus Bank (“Pegasus”), for an aggregate cash purchase price of $123.5 million. Pegasus is a Texas chartered bank with three banking locations in Dallas, Texas. As of December 31, 2018, Pegasus had approximately $639.1 million in total assets, $367.4 million in loans and $595.3 million in deposits. The acquisition is expected to be completed during the third quarter of 2019. Upon acquisition, Pegasus will continue to operate as “Pegasus Bank” under a separate Texas charter and remain an independent subsidiary of BancFirst Corporation governed by its existing board of directors. BancFirst Corporation intends to provide an appropriate amount of capital or other support to increase Pegasus’ ability to approve larger loans and allow Pegasus to continue to grow their assets. On August 31, 2018, BFTower, LLC, a wholly-owned subsidiary of BancFirst On January 11, 2018, the Company acquired First Wagoner Corp. and its subsidiary bank, First Bank & Trust Company, with locations in Carney, Grove, Ketchum, Luther, Tulsa and Wagoner. First Bank & Trust Company had approximately $290 million in total assets, $247 million in loans and $251 million in deposits. First Bank & Trust Company operated as a subsidiary of BancFirst Corporation until it was merged into BancFirst on February 16, 2018. As a result of the acquisition, the Company recorded a core deposit intangible of approximately $6.3 million and goodwill of approximately $19.1 million. The effect of this acquisition was included in the consolidated financial statements of the Company from the date of acquisition forward. The acquisition did not have a material effect on the Company’s consolidated financial statements. The acquisition of First Wagoner Corp. and its subsidiary bank, First Bank & Trust Company complements the Company’s community banking strategy by adding an additional five communities to its banking network in Oklahoma. On January 11, 2018, the Company acquired First Chandler Corp. and its subsidiary bank, First Bank of Chandler, with two locations in Chandler. First Bank of Chandler had approximately $88 million in total assets, $66 million in loans and $79 million in deposits. First Bank of Chandler operated as a subsidiary of BancFirst Corporation until it was merged into BancFirst on September 7, 2018. As a result of the acquisition, the Company recorded a core deposit intangible of approximately $2.2 million and goodwill of approximately $6.6 million. The effect of this acquisition was included in the consolidated financial statements of the Company from the date of acquisition forward. The acquisition did not have a material effect on the Company’s consolidated financial statements. The acquisition of First Chandler Corp. and its subsidiary bank, First Bank of Chandler complements the Company’s community banking strategy by increasing its banking network in Oklahoma.

Securities

Securities	6 Months Ended
	Jun. 30, 2019
Investments Debt And Equity Securities [Abstract]
Securities	( 3 ) SECURITIES The following table summarizes the amortized cost and estimated fair values of debt securities held for investment: Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value June 30, 2019 (Dollars in thousands) Mortgage backed securities (1) $ 112 $ 6 $ — $ 118 States and political subdivisions 1,385 1 (1 ) 1,385 Other securities 500 — — 500 Total $ 1,997 $ 7 $ (1 ) $ 2,003 December 31, 2018 Mortgage backed securities (1) $ 133 $ 5 $ — $ 138 States and political subdivisions 795 — — 795 Other securities 500 — — 500 Total $ 1,428 $ 5 $ — $ 1,433 The following table summarizes the amortized cost and estimated fair values of debt securities available for sale: Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value June 30, 2019 (Dollars in thousands) U.S. treasuries $ 353,618 $ 5,371 $ (355 ) $ 358,634 U.S. federal agencies 26,169 12 (26 ) 26,155 Mortgage backed securities (1) 15,646 138 (565 ) 15,219 States and political subdivisions 22,820 335 (6 ) 23,149 Total $ 418,253 $ 5,856 $ (952 ) $ 423,157 December 31, 2018 U.S. treasuries $ 699,882 $ 1,108 $ (3,524 ) $ 697,466 U.S. federal agencies 30,079 — (160 ) 29,919 Mortgage backed securities (1) 16,367 114 (573 ) 15,908 States and political subdivisions 27,246 277 (112 ) 27,411 Total $ 773,574 $ 1,499 $ (4,369 ) $ 770,704 (1) Primarily consists of FHLMC, FNMA, GNMA and mortgage backed securities through U.S. agencies. The maturities of debt 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. June 30, 2019 December 31, 2018 Amortized Cost Estimated Fair Value Amortized Cost Estimated Fair Value (Dollars in thousands) Held for Investment Contractual maturity of debt securities: Within one year $ 300 $ 301 $ 495 $ 495 After one year but within five years 1,146 1,147 369 370 After five years but within ten years 549 553 562 565 After ten years 2 2 2 3 Total $ 1,997 $ 2,003 $ 1,428 $ 1,433 Available for Sale Contractual maturity of debt securities: Within one year $ 103,395 $ 103,084 $ 411,256 $ 410,327 After one year but within five years 270,900 276,333 313,416 311,924 After five years but within ten years 6,355 6,606 7,524 7,685 After ten years 37,603 37,134 41,378 40,768 Total debt securities $ 418,253 $ 423,157 $ 773,574 $ 770,704 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: June 30, 2019 December 31, 2018 (Dollars Book value of pledged securities $ 402,756 $ 472,053

Loans and Allowance for Loan Lo

Loans and Allowance for Loan Losses	6 Months Ended
	Jun. 30, 2019
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: June 30, 2019 December 31, 2018 Amount Percent Amount Percent (Dollars in thousands) Commercial and financial: Commercial and industrial $ 1,062,527 20.86 % $ 1,032,787 20.76 % Oil & gas production and equipment 122,268 2.40 94,729 1.90 Agriculture 130,957 2.57 136,313 2.74 State and political subdivisions: Taxable 74,596 1.46 76,211 1.53 Tax-exempt 51,114 1.00 48,415 0.97 Real estate: Construction 450,525 8.84 451,224 9.07 Farmland 227,635 4.47 219,241 4.41 One to four family residences 990,377 19.44 979,170 19.68 Multifamily residential properties 68,743 1.35 65,949 1.33 Commercial 1,525,064 29.94 1,506,937 30.28 Consumer 345,783 6.79 328,069 6.59 Other (not classified above) 44,814 0.88 36,931 0.74 Total loans $ 5,094,403 100.00 % $ 4,975,976 100.00 % The Company’s loans are mostly to customers within Oklahoma and approximately % of the loans are secured by real estate. Credit risk on loans is managed through limits on amounts loaned to individual and related 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. The Company’s commercial and industrial loan category includes a small percentage of loans to companies that provide ancillary services to the oil and gas industry, such as transportation, preparation contractors and equipment manufacturers. The balance of these loans was approximately $74 million at June 30, 2019 and approximately $60 million at December 31, 2018. 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, 2018. Nonperforming and Restructured Assets The following is a summary of nonperforming and restructured assets: June 30, December 31, 2019 2018 (Dollars in thousands) Past due 90 days or more and still accruing $ 2,663 $ 1,916 Nonaccrual 17,998 22,603 Restructured 16,486 13,188 Total nonperforming and restructured loans 37,147 37,707 Other real estate owned and repossessed assets 7,004 6,873 Total nonperforming and restructured assets $ 44,151 $ 44,580 Had nonaccrual loans performed in accordance with their original contractual terms, the Company would have recognized additional interest income of approximately $1.0 million for the six months ended June 30, 2019 and approximately $1.1 million for the six months ended June 30, 2018. The Company charges interest on principal balances outstanding on restructured loans during deferral periods. 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. June 30, 2019 December 31, 2018 (Dollars in thousands) Real estate: Non-residential real estate owner occupied $ 1,127 $ 838 Non-residential real estate other 674 187 Residential real estate permanent mortgage 1,585 954 Residential real estate all other 5,327 5,488 Commercial and financial: Non-consumer non-real estate 2,958 5,682 Consumer non-real estate 394 437 Other loans 272 490 Acquired loans 5,661 8,527 Total $ 17,998 $ 22,603 Loans are considered past due if the required principal and interest payments have not been received as of the date such payments were due. The following table presents an age analysis of past due loans, segregated by class of loans: Age Analysis of Past Due Loans 30-59 Days Past Due 60-89 Days Past Due 90 Days and Greater Total Past Due Loans Current Loans Total Loans Accruing Loans 90 Days or More Past Due (Dollars in thousands) As of June 30, 2019 Real estate: Non-residential real estate owner occupied $ 4,203 $ 852 $ 536 $ 5,591 $ 649,600 $ 655,191 $ 117 Non-residential real estate other 1,088 — 325 1,413 1,179,092 1,180,505 177 Residential real estate permanent mortgage 2,583 760 986 4,329 330,046 334,375 384 Residential real estate all other 2,218 340 4,908 7,466 849,448 856,914 150 Commercial and financial: Non-consumer non-real estate 1,652 918 2,099 4,669 1,360,458 1,365,127 454 Consumer non-real estate 1,846 540 470 2,856 342,684 345,540 232 Other loans 220 1,083 183 1,486 142,387 143,873 183 Acquired loans 2,583 882 3,592 7,057 205,821 212,878 966 Total $ 16,393 $ 5,375 $ 13,099 $ 34,867 $ 5,059,536 $ 5,094,403 $ 2,663 As of December 31, 2018 Real estate: Non-residential real estate owner occupied $ 5,114 $ 810 $ 43 $ 5,967 $ 620,654 $ 626,621 $ — Non-residential real estate other 2,772 32 114 2,918 1,143,210 1,146,128 — Residential real estate permanent mortgage 2,448 653 693 3,794 324,908 328,702 430 Residential real estate all other 1,728 292 2,799 4,819 822,685 827,504 612 Commercial and financial: Non-consumer non-real estate 3,620 702 833 5,155 1,278,499 1,283,654 282 Consumer non-real estate 1,991 565 559 3,115 323,747 326,862 325 Other loans 322 158 178 658 141,251 141,909 — Acquired loans 5,240 1,669 4,936 11,845 282,751 294,596 267 Total $ 23,235 $ 4,881 $ 10,155 $ 38,271 $ 4,937,705 $ 4,975,976 $ 1,916 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. During the period ended June 30, 2019 and June 30, 2018, no material amount of interest income was recognized on impaired loans subsequent to their classification as impaired. Impaired Loans Unpaid Principal Balance Recorded Investment with Allowance Related Allowance Average Recorded Investment (Dollars in thousands) As of June 30, 2019 Real estate: Non-residential real estate owner occupied $ 8,051 $ 7,933 $ 239 $ 7,662 Non-residential real estate other 1,687 1,422 190 1,615 Residential real estate permanent mortgage 2,427 2,151 183 1,964 Residential real estate all other 6,629 6,350 3,081 6,529 Commercial and financial: Non-consumer non-real estate 18,389 10,842 931 10,944 Consumer non-real estate 781 672 149 691 Other loans 659 455 17 322 Acquired loans 9,553 7,244 2 8,863 Total $ 48,176 $ 37,069 $ 4,792 $ 38,590 As of December 31, 2018 Real estate: Non-residential real estate owner occupied $ 7,126 $ 6,933 $ 202 $ 7,739 Non-residential real estate other 949 757 50 6,057 Residential real estate permanent mortgage 1,789 1,545 127 1,650 Residential real estate all other 7,177 6,862 2,433 7,154 Commercial and financial: Non-consumer non-real estate 18,507 10,977 881 12,140 Consumer non-real estate 928 829 131 846 Other loans 710 490 35 481 Acquired loans 12,846 9,864 2 11,050 Total $ 50,032 $ 38,257 $ 3,861 $ 47,117 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, 2018. 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 June 30, 2019 Real estate: Non-residential real estate owner occupied $ 457,211 $ 171,239 $ 25,491 $ 1,250 $ — $ 655,191 Non-residential real estate other 950,058 202,397 27,291 759 — 1,180,505 Residential real estate permanent mortgage 281,593 43,479 7,242 2,061 — 334,375 Residential real estate all other 669,269 167,518 14,375 5,752 — 856,914 Commercial and financial: Non-consumer non-real estate 1,077,429 252,175 33,630 1,893 — 1,365,127 Consumer non-real estate 320,278 21,955 2,707 565 35 345,540 Other loans 138,414 4,160 1,289 10 — 143,873 Acquired loans 124,437 71,790 9,751 6,603 297 212,878 Total $ 4,018,689 $ 934,713 $ 121,776 $ 18,893 $ 332 $ 5,094,403 As of December 31, 2018 Real estate: Non-residential real estate owner occupied $ 451,059 $ 157,715 $ 16,949 $ 898 $ — $ 626,621 Non-residential real estate other 932,454 188,341 25,146 187 — 1,146,128 Residential real estate permanent mortgage 279,870 39,806 7,401 1,625 — 328,702 Residential real estate all other 644,217 162,003 15,232 6,052 — 827,504 Commercial and financial: Non-consumer non-real estate 1,000,089 264,134 15,128 4,303 — 1,283,654 Consumer non-real estate 302,217 21,600 2,255 790 — 326,862 Other loans 136,132 5,542 116 119 — 141,909 Acquired loans 156,008 109,075 20,884 8,284 345 294,596 Total $ 3,902,046 $ 948,216 $ 103,111 $ 22,258 $ 345 $ 4,975,976 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, 2018. 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 categories. ALL Balance at beginning of period Charge- offs Recoveries Net charge-offs Provisions charged to operations Balance at end of period (Dollars in thousands) Three Months Ended June 30, 2019 Real estate: Non-residential real estate owner occupied $ 6,655 $ (3 ) $ — $ (3 ) $ 235 $ 6,887 Non-residential real estate other 11,362 (16 ) 1 (15 ) (60 ) 11,287 Residential real estate permanent mortgage 3,261 (4 ) 4 — 64 3,325 Residential real estate all other 11,046 (143 ) 25 (118 ) 793 11,721 Commercial and financial: Non-consumer non-real estate 14,409 (87 ) 85 (2 ) 825 15,232 Consumer non-real estate 3,072 (162 ) 38 (124 ) 286 3,234 Other loans 2,408 — 43 43 (2 ) 2,449 Acquired loans 702 (170 ) 149 (21 ) 292 973 Total $ 52,915 $ (585 ) $ 345 $ (240 ) $ 2,433 $ 55,108 Six Months Ended June 30, 2019 Real estate: Non-residential real estate owner occupied $ 6,328 $ (9 ) $ 1 $ (8 ) $ 567 $ 6,887 Non-residential real estate other 11,027 (22 ) 1 (21 ) 281 11,287 Residential real estate permanent mortgage 3,261 (67 ) 9 (58 ) 122 3,325 Residential real estate all other 10,673 (195 ) 27 (168 ) 1,216 11,721 Commercial and financial: Non-consumer non-real estate 13,151 (157 ) 152 (5 ) 2,086 15,232 Consumer non-real estate 3,065 (282 ) 109 (173 ) 342 3,234 Other loans 2,423 — 78 78 (52 ) 2,449 Acquired loans 1,461 (196 ) 153 (43 ) (445 ) 973 Total $ 51,389 $ (928 ) $ 530 $ (398 ) $ 4,117 $ 55,108 ALL Balance at beginning of period Charge- offs Recoveries Net charge-offs Provisions charged to operations Balance at end of period (Dollars in thousands) Three Months Ended June 30, 2018 Real estate: Non-residential real estate owner occupied $ 6,650 $ — $ — $ — $ (224 ) $ 6,426 Non-residential real estate other 10,548 — — — 157 10,705 Residential real estate permanent mortgage 3,281 (6 ) 23 17 9 3,307 Residential real estate all other 9,831 (151 ) 3 (148 ) 440 10,123 Commercial and financial: Non-consumer non-real estate 14,785 (153 ) 10 (143 ) 427 15,069 Consumer non-real estate 2,699 (194 ) 44 (150 ) 290 2,839 Other loans 2,336 (2 ) 12 10 (18 ) 2,328 Acquired loans 1,420 (166 ) 5 (161 ) 144 1,403 Total $ 51,550 $ (672 ) $ 97 $ (575 ) $ 1,225 $ 52,200 Six Months Ended June 30, 2018 Real estate: Non-residential real estate owner occupied $ 6,195 $ (19 ) $ 1 $ (18 ) $ 249 $ 6,426 Non-residential real estate other 10,519 (1 ) 39 38 148 10,705 Residential real estate permanent mortgage 3,226 (62 ) 26 (36 ) 117 3,307 Residential real estate all other 9,672 (241 ) 6 (235 ) 686 10,123 Commercial and financial: Non-consumer non-real estate 15,334 (309 ) 23 (286 ) 21 15,069 Consumer non-real estate 2,793 (444 ) 124 (320 ) 366 2,839 Other loans 2,481 (2 ) 24 22 (175 ) 2,328 Acquired loans 1,446 (193 ) 23 (170 ) 127 1,403 Total $ 51,666 $ (1,271 ) $ 266 $ (1,005 ) $ 1,539 $ 52,200 The following table details the amount of ALL by class of loans for the period presented, detailed on the basis of the impairment methodology used by the Company. ALL June 30, 2019 December 31, 2018 Individually evaluated for impairment Collectively evaluated for impairment Individually evaluated for impairment Collectively evaluated for impairment (Dollars in thousands) Real estate: Non-residential real estate owner occupied $ 1,003 $ 5,884 $ 669 $ 5,659 Non-residential real estate other 1,055 10,232 1,119 9,908 Residential real estate permanent mortgage 508 2,817 505 2,756 Residential real estate all other 4,189 7,532 3,413 7,260 Commercial and financial: Non-consumer non-real estate 3,679 11,553 2,114 11,037 Consumer non-real estate 427 2,807 374 2,691 Other loans 10 2,439 65 2,358 Acquired loans — 973 — 1,461 Total $ 10,871 $ 44,237 $ 8,259 $ 43,130 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 June 30, 2019 December 31, 2018 Individually evaluated for impairment Collectively evaluated for impairment Loans acquired with deteriorated credit quality Individually evaluated for impairment Collectively evaluated for impairment Loans acquired with deteriorated credit quality (Dollars in thousands) Real estate: Non-residential real estate owner occupied $ 26,741 $ 628,450 $ — $ 17,846 $ 608,775 $ — Non-residential real estate other 28,050 1,152,455 — 25,333 1,120,795 — Residential real estate permanent mortgage 9,303 325,072 — 9,026 319,676 — Residential real estate all other 20,127 836,787 — 21,285 806,219 — Commercial and financial: Non-consumer non-real estate 35,523 1,329,604 — 19,432 1,264,222 — Consumer non-real estate 3,304 342,236 — 3,093 323,769 — Other loans 10 143,863 — 209 141,700 — Acquired loans 14,399 196,226 2,253 22,132 265,084 7,380 Total $ 137,457 $ 4,954,693 $ 2,253 $ 118,356 $ 4,850,240 $ 7,380 Non-Cash Transfers from Loans and Premises and Equipment Transfers from loans and premises and equipment to other real estate owned and repossessed assets are non-cash transactions, and are not included in the statements of cash flow. Such transfers during the periods presented, are summarized as follows: Six Months Ended June 30, 2019 2018 (Dollars in thousands) Other real estate owned $ 2,010 $ 1,123 Repossessed assets 627 550 Total $ 2,637 $ 1,673

Intangible Assets

Intangible Assets	6 Months Ended
	Jun. 30, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Intangible Assets	( 5 ) INTANGIBLE ASSETS The following is a summary of intangible assets: Gross Carrying Amount Accumulated Amortization Net Carrying Amount (Dollars in thousands) As of June 30, 2019 Core deposit intangibles $ 25,907 $ (12,456 ) $ 13,451 Customer relationship intangibles 5,699 (4,289 ) 1,410 Mortgage servicing intangibles 388 (313 ) 75 Total $ 31,994 $ (17,058 ) $ 14,936 As of December 31, 2018 Core deposit intangibles $ 25,907 $ (11,113 ) $ 14,794 Customer relationship intangibles 5,699 (4,115 ) 1,584 Mortgage servicing intangibles 397 (305 ) 92 Total $ 32,003 $ (15,533 ) $ 16,470 The following is a summary of goodwill by business segment: Other Executive, Metropolitan Community Financial Operations Banks Banks Services & Support Consolidated (Dollars in thousands) Six months ended June 30, 2019 Balance at beginning and end of period $ 13,767 $ 59,894 $ 5,464 $ 624 $ 79,749 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, 2018.

Leases

Leases	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Leases	(6) LEASES Lessee On January 1, 2019, the Company adopted ASU No. 2016-02, “Leases - (Topic 842),” which requires the recognition of the Company’s operating leases on its balance sheet. See Note (1) for additional information. The Company has operating leases, which primarily consist of office space in buildings, ATM locations, storage facilities, parking lots and land on which it owns certain buildings. Rent expense for all operating leases totaled approximately $343,000 and $395,000 for the three months ended June 30, 2019 and June 30, 2018, respectively. Rent expense for all operating leases totaled approximately $700,000 and $776,000 for the six months ended June 30, 2019 and June 30, 2018, respectively. As of June 30, 2019, a right of use lease asset included in accrued interest receivable and other assets on the balance sheet totaled $5.3 million, and a related lease liability included in accrued interest payable and other liabilities on the balance sheet totaled $5.2 million. There have been no significant changes in our expected future minimum lease payments since December 31, 2018, which are disclosed in Note (19) to the Company’s Annual Report on Form 10-K for the year ended December 31, 2018. As of June 30, 2019, our operating leases have a weighted-average remaining lease term of 4.5 years and a weighted-average discount rate of 3.6 percent. Maturity of Operating Lease Liabilities June 30, 2019 (Dollars in thousands) 2019 (six months) $ 55 2020 829 2021 114 2022 1,542 2023 636 Thereafter 2,072 Operating Lease Liability $ 5,248 Lessor The Company is a lessor of operating leases, which primarily consist of office space in buildings and parking lots. These assets are classified on the balance sheet as premises and equipment. The Company had operating lease revenue of $1.5 million for the three months ended June 30, 2019 and $3.1 million for the six months ended June 30, 2019, which is included in occupancy, net on the consolidated statement of comprehensive income. Future Minimum Lease Payments to be received The Company does not have operating leases that extend beyond 2024. The following table presents the scheduled minimum future contractual rent to be received under the remaining non-cancelable term of the operating leases: June 30, 2019 (Dollars in thousands) 2019 (six months) $ 2,129 2020 2,681 2021 1,788 2022 1,141 2023 681 2024 75 Total Future Minimum Lease Payments $ 8,495

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	( 7 ) STOCK-BASED COMPENSATION The Company adopted a nonqualified incentive stock option plan (the “BancFirst ISOP”) in May 1986. The Company has amended the BancFirst ISOP since 1986 to increase the number of shares to be issued under the plan to 6,484,530 shares. At June 30, 2019, there were 350,000 shares available for future grants. The BancFirst ISOP will terminate on December 31, 2024, if not extended. 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 June 30, 2019 will become exercisable through the year 2026. 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 has amended the BancFirst Directors’ Stock Option Plan since 1999 to increase the number of shares to be issued under the plan to 530,000 shares. At June 30, 2019, there were 50,000 shares available for future grants. The BancFirst Directors’ Stock Option Plan will terminate on December 31, 2024, if not extended. 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 June 30, 2019 will become exercisable through the year 2023. 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: Wgtd. Avg. Wgtd. Avg. Remaining Aggregate Exercise Contractual Intrinsic Options Price Term Value (Dollars in thousands, except option data) Six Months Ended June 30, 2019 Outstanding at December 31, 2018 1,216,700 $ 28.48 Options granted 40,000 55.38 Options exercised (27,300 ) 22.37 Options canceled, forfeited, or expired (22,500 ) 51.83 Outstanding at June 30, 2019 1,206,900 29.07 9.20 Yrs $ 32,090 Exercisable at June 30, 2019 648,400 22.49 7.08 Yrs $ 21,506 The following table has additional information regarding options exercised under both the BancFirst ISOP and the BancFirst Directors’ Stock Option Plan: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (Dollars in thousands) (Dollars in thousands) Total intrinsic value of options exercised $ 759 $ 967 $ 904 $ 3,827 Cash received from options exercised 455 411 611 1,644 Tax benefit realized from options exercised 193 246 230 975 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 June 30, Six Months Ended June 30, 2019 2018 2019 2018 (Dollars in thousands) (Dollars in thousands) Stock-based compensation expense $ 367 $ 322 $ 541 $ 628 Tax benefit 94 82 138 160 Stock-based compensation expense, net of tax $ 273 $ 240 $ 403 $ 468 The Company will continue to amortize the unearned stock-based compensation expense over the remaining vesting period of approximately seven years. The following table shows the unearned stock-based compensation expense: June 30, 2019 (Dollars in thousands) Unearned stock-based compensation expense $ 3,198 The following table shows the assumptions used for computing stock-based compensation expense under the fair value method on options granted during the periods presented: Six Months Ended June 30, 2019 2018 Weighted average grant-date fair value per share of options granted $ 13.67 $ 13.98 Risk-free interest rate 2.62 to 2.76% 2.55 to 2.92% Dividend yield 2.00% 2.00% Stock price volatility 22.93 to 22.96% 23.05 to 23.29% Expected term 10 Yrs 10 Yrs The risk-free interest rate is determined by reference to the spot zero-coupon rate for the U.S. Treasury security with a maturity similar to the expected term of the options. The dividend yield is the expected yield for the expected term. The stock price volatility is estimated from the recent historical volatility of the Company’s stock. The expected term is estimated from the historical option exercise experience. The Company accounts for forfeitures as they occur. In May 1999, the Company adopted the BancFirst Corporation Directors’ Deferred Stock Compensation Plan (the “BancFirst Deferred Stock Compensation Plan”). The Company has amended the BancFirst Deferred Stock Compensation Plan since 1999 to increase the number of shares to be issued under the plan to 244,148 shares. The BancFirst Deferred Stock Compensation Plan will terminate on December 31, 2024, if not extended. Under the plan, directors and members of the community advisory boards of the Company and its subsidiaries may defer up to 100% of their board fees. They are credited for each deferral with a number of stock units based on the current market price of the Company’s stock, which accumulate in an account until such time as the director or community board member terminates serving as a board member. Shares of common stock of the Company are then distributed to the terminating director or community board member based upon the number of stock units accumulated in his or her account. There were 8,362 and 3,891 shares of common stock distributed from the BancFirst Deferred Stock Compensation Plan during the six months ended June 30, 2019 and June 30, 2018, respectively. A summary of the accumulated stock units is as follows: June 30, December 31, 2019 2018 Accumulated stock units 139,862 143,347 Average price $ 26.19 $ 24.91

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2019
Equity [Abstract]
Stockholders' Equity	( 8 ) 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: Six Months Ended June 30, 2019 2018 Number of shares repurchased — — Average price of shares repurchased $ — $ — Shares remaining to be repurchased 148,736 300,000 The Company and BancFirst are subject to risk-based capital guidelines issued by the Board of Governors of the Federal Reserve System and the Federal Deposit Insurance Corporation (“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 June 30, 2019, 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: Required To Be Well For Capital With Capitalized Under Adequacy Capital Conservation Prompt Corrective Actual Purposes Buffer Action Provisions Amount Ratio Amount Ratio Amount Ratio Amount Ratio (Dollars in thousands) As of June 30, 2019: Total Capital (to Risk Weighted Assets)- BancFirst Corporation $ 939,223 16.71% $ 449,674 8.00% $ 590,197 10.50% N/A N/A BancFirst 813,627 14.50% 448,824 8.00% 589,082 10.50% $ 561,030 10.00% Common Equity Tier 1 Capital (to Risk Weighted Assets)- BancFirst Corporation $ 858,115 15.27% $ 252,942 4.50% $ 393,465 7.00% N/A N/A BancFirst 738,519 13.16% 252,464 4.50% 392,721 7.00% $ 364,670 6.50% Tier 1 Capital (to Risk Weighted Assets)- BancFirst Corporation $ 884,115 15.73% $ 337,256 6.00% $ 477,779 8.50% N/A N/A BancFirst 758,519 13.52% 336,618 6.00% 476,876 8.50% $ 448,824 8.00% Tier 1 Capital (to Total Assets)- BancFirst Corporation $ 884,115 11.64% $ 303,864 4.00% N/A N/A N/A N/A BancFirst 758,519 10.01% 303,252 4.00% N/A N/A $ 379,065 5.00% As of June 30, 2019, the most recent notification from the Federal Reserve Bank of Kansas City and the FDIC categorized BancFirst as “well capitalized” under the regulatory framework from prompt corrective action. The Company’s trust preferred securities have continued to be included in Tier 1 capital as the Company’s total assets do not exceed $15 billion. There are no conditions or events since the most recent notifications of BancFirst’s capital category that management believes would materially change its category under capital requirements existing as of the report date. Basel III Capital Rules Under the Basel III Capital Rules, 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. As of June 30, 2019, the Company and BancFirst met all capital adequacy requirements under the Basel III Capital Rules.

Net Income Per Common Share

Net Income Per Common Share	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Net Income Per Common Share	( 9 ) NET INCOME PER COMMON SHARE Basic and diluted net income per common share based on weighted-average shares outstanding are calculated as follows: Income (Numerator) Shares (Denominator) Per Share Amount (Dollars in thousands, except per share data) Three Months Ended June 30, 2019 Basic Income available to common stockholders $ 34,167 32,629,146 $ 1.04 Dilutive effect of stock options — 688,047 Diluted Income available to common stockholders plus assumed exercises of stock options $ 34,167 33,317,193 $ 1.02 Three Months Ended June 30, 2018 Basic Income available to common stockholders $ 30,586 32,716,350 $ 0.93 Dilutive effect of stock options — 742,207 Diluted Income available to common stockholders plus assumed exercises of stock options $ 30,586 33,458,557 $ 0.91 Six Months Ended June 30, 2019 Basic Income available to common stockholders $ 66,004 32,620,819 $ 2.02 Dilutive effect of stock options — 685,610 Diluted Income available to common stockholders plus assumed exercises of stock options $ 66,004 33,306,429 $ 1.98 Six Months Ended June 30, 2018 Basic Income available to common stockholders $ 60,206 32,645,693 $ 1.84 Dilutive effect of stock options — 744,269 Diluted Income available to common stockholders plus assumed exercises of stock options $ 60,206 33,389,962 $ 1.80 The following table shows the number of options that were excluded from the computation of diluted net income per common share for each period because the options were anti-dilutive for the period: Shares Three Months Ended June 30, 2019 158,500 Three Months Ended June 30, 2018 85,802 Six Months Ended June 30, 2019 169,301 Six Months Ended June 30, 2018 117,696

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	( 10 ) 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 Accounting Standards Codification (“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: • Level 1 Inputs to the valuation methodology are quoted prices (unadjusted) for identical assets or liabilities in active markets. • 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. • 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, repossessed assets, other real estate owned, 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, registered 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 private label mortgage backed securities 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 replacement cost, 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 portfolio primarily 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 for pricing mentioned in the preceding paragraph adjusted for the specific issue. Periodically, the Company will validate 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. The following table summarizes financial assets and financial liabilities measured at fair value on a recurring basis as of the periods presented, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value: Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Fair Value (Dollars in thousands) June 30, 2019 Securities available for sale: U.S. Treasury $ 358,634 $ — $ — $ 358,634 U.S. federal agencies — 26,155 — 26,155 Mortgage-backed securities — 2,164 13,055 15,219 States and political subdivisions — 23,149 — 23,149 Derivative assets — 19 — 19 Derivative liabilities — 17 — 17 December 31, 2018 Securities available for sale: U.S. Treasury $ 697,466 $ — $ — $ 697,466 U.S. federal agencies — 29,919 — 29,919 Mortgage-backed securities — 2,465 13,443 15,908 States and political subdivisions — 27,411 — 27,411 Derivative assets — 252 — 252 Derivative liabilities — 238 — 238 The changes in Level 3 assets measured at estimated fair value on a recurring basis during the periods presented were as follows: Six Months Ended June 30, Twelve Months Ended December 31, 2019 2018 (Dollars in thousands) Balance at the beginning of the year $ 13,443 $ 14,467 Settlements (396 ) (1,037 ) Total unrealized (losses) gains 8 13 Balance at the end of the period $ 13,055 $ 13,443 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 June 30, 2019 and 2018, 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. The Company invests in equity securities without readily determinable fair values and utilizes Level 3 inputs. Beginning January 1, 2018, upon adoption of ASU 2016-01, these securities are reported at cost minus impairment, if any, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer. The realized and unrealized gains and losses are reported as securities transactions in the noninterest income section of the consolidated statements of comprehensive income. 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. Repossessed 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 repossessed 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. The fair value represents end of period values, which approximate fair value measurements that occurred on various measurement dates throughout the period: Total Fair Value Level 3 (Dollars in thousands) As of and for the Year-to-date Period Ended June 30, 2019 Equity securities $ 9,099 Impaired loans (less specific allowance) 32,277 Repossessed assets 201 Other real estate owned 1,759 As of and for the Year-to-date Period Ended December 31, 2018 Equity securities $ 7,521 Impaired loans (less specific allowance) 34,396 Repossessed assets 183 Other real estate owned 4,683 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 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 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. Loans To determine the fair value of loans, the Company uses an exit price calculation, which takes into account factors such as liquidity, credit and the nonperformance risk of 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. 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: June 30, December 31, 2019 2018 Carrying Amount Fair Value Carrying Amount Fair Value (Dollars in thousands) FINANCIAL ASSETS Level 2 inputs: Cash and cash equivalents $ 1,704,438 $ 1,704,438 $ 1,424,255 $ 1,424,255 Securities held for investment 1,497 1,503 928 933 Loans held for sale 10,899 10,899 8,174 8,174 Level 3 inputs: Securities held for investment 500 500 500 500 Loans, net of allowance for loan losses 5,039,295 5,052,074 4,924,587 4,901,159 FINANCIAL LIABILITIES Level 2 inputs: Deposits 6,613,613 6,729,518 6,605,495 6,713,542 Short-term borrowings 1,000 1,000 1,675 1,675 Junior subordinated debentures 26,804 28,777 26,804 29,549 OFF-BALANCE SHEET FINANCIAL INSTRUMENTS Loan commitments 2,277 2,158 Letters of credit 414 421 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 periodically) 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 June 30, 2019 or December 31, 2018.

Segment Information

Segment Information	6 Months Ended
	Jun. 30, 2019
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 Banks Community Banks Other Financial Services Executive, Operations & Support Eliminations Consolidated (Dollars in thousands) Three Months Ended June 30, 2019 Net interest income $ 21,438 $ 44,775 $ 1,411 $ 1,168 $ — $ 68,792 Noninterest income 4,635 16,243 10,105 37,917 (34,823 ) 34,077 Income before taxes 14,866 30,041 5,572 27,590 (34,241 ) 43,828 Three Months Ended June 30, 2018 Net interest income $ 21,084 $ 42,068 $ 1,358 $ 370 $ — $ 64,880 Noninterest income 4,184 14,832 8,896 33,609 (31,084 ) 30,437 Income before taxes 14,883 27,942 4,028 23,622 (30,639 ) 39,836 Six Months Ended June 30, 2019 Net interest income $ 42,791 $ 88,182 $ 2,582 $ 2,140 $ — $ 135,695 Noninterest income 8,844 31,128 19,978 73,438 (67,310 ) 66,078 Income before taxes 30,235 58,086 10,071 52,613 (66,163 ) 84,842 Six Months Ended June 30, 2018 Net interest income $ 41,388 $ 83,450 $ 2,833 $ 244 $ — $ 127,915 Noninterest income 8,125 28,785 18,520 65,803 (60,686 ) 60,547 Income before taxes 29,619 54,290 9,071 43,537 (59,740 ) 76,777 Total Assets: June 30, 2019 $ 2,795,525 $ 4,981,139 $ 45,972 $ 883,471 $ (1,064,086 ) $ 7,642,021 December 31, 2018 2,743,876 4,892,946 84,706 861,782 (1,009,052 ) 7,574,258 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 S_2

Description of Business and Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2019
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., BancFirst Risk & Insurance Company and BancFirst and its subsidiaries. The principal operating subsidiaries of BancFirst are Council Oak Investment Corporation, Council Oak Real Estate, Inc., BFTower, LLC and BancFirst Agency, Inc. All significant intercompany accounts and transactions have been eliminated. Assets held in a fiduciary or agency capacity are not assets of the Company and, accordingly, are not included in the unaudited interim consolidated financial statements. The accompanying unaudited interim consolidated financial statements and notes are presented in accordance with the instructions for Form 10-Q. The information contained in the financial statements and footnotes included in BancFirst Corporation’s Annual Report on Form 10-K for the year ended December 31, 2018, should be referred to in connection with these unaudited interim consolidated financial statements. Operating results for the interim periods disclosed herein are not necessarily indicative of the results that may be expected for a full year or any future period. The unaudited interim consolidated financial statements contained herein reflect all adjustments which are, in the opinion of management, necessary to provide a fair statement of the financial position and results of operations of the Company for the interim periods presented. All such adjustments are of a normal and recurring nature. There have been no significant changes in the accounting policies of the Company since December 31, 2018, the date of the most recent annual report.
Reclassifications	Reclassifications Certain items in prior financial statements have been reclassified to conform to the current presentation. Such reclassifications had no effect on previously reported net cash flows, stockholders’ equity or comprehensive income.
Use of Estimates in the Preparation of Financial Statements	Use of Estimates in the Preparation of Financial Statements The preparation of financial statements in conformity with accounting principles generally accepted in the United States inherently involves the use of estimates and assumptions that affect the amounts reported in the financial statements and the related disclosures. These estimates relate principally to the determination of the allowance for loan losses, income taxes, the fair value of financial instruments and the valuation of intangibles. Such estimates and assumptions may change over time and actual amounts realized may differ from those reported.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Standards Adopted During Current Period: In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-02, “Leases - (Topic 842)”, amended by ASU 2018-11, “Leases – (Topic 842)”: Targeted Improvements. This new guidance requires a lessee to recognize on the balance sheet the assets and liabilities for the rights and obligations created by leases with lease terms of more than twelve months and provide additional disclosures. The amendments were effective for annual periods, and interim reporting periods within those annual periods, beginning after December 15, 2018. The Company adopted this new standard on January 1, 2019, using a modified retrospective transition approach and recognized right-of-use lease assets and related lease liabilities totaling $4.3 million . Standards Not Yet Adopted: In August 2018, the FASB issued ASU No. 2018-13, “Fair Value Measurement (Topic 820).” ASU 2018-13 removes, modifies and adds disclosure requirements on fair value measurements. ASU 2018-13 will be effective for the Company on January 1, 2020. Early adoption is permitted. In addition, early adoption of any removed or modified disclosures and delayed adoption of the additional disclosures until the effective date is also permitted. The Company expects to adopt the standard in the first quarter of 2020. In June 2016, the FASB issued ASU No. 2016-13, “Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” ASU 2016-13 requires a financial asset measured at amortized cost basis to be presented at the net amount expected to be collected. The measurement of expected credit losses is based on relevant information about past events, including historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. ASU 2016-13 requires enhanced disclosures related to the significant estimates and judgements used in estimating credit losses, as well as the credit quality and underwriting standards of an organization’s portfolio. In addition, ASU 2016-13 amends the accounting for credit losses on available-for-sale debt securities and purchased financial assets with credit deterioration. ASU 2016-13 will be effective for the Company on January 1, 2020. The Company is currently evaluating the potential impact of ASU 2016-13 on its financial statements. In that regard, the Company has formed a task force under the direction of its Chief Financial Officer. In preparation, the Company has developed new credit estimation models, processes and controls. Internal validation of the model is underway and expected to be completed during the third quarter of 2019. The Company has performed test runs of the new processes and controls and will begin full parallel runs next quarter. The adoption of ASU 2016-13 could result in an increase or decrease in the allowance for loan losses as a result of changing from an “incurred loss” model, which encompasses allowances for current known and inherent losses within the portfolio, to an “expected loss” model, which encompasses allowances for losses expected to be incurred over the life of the portfolio. Furthermore, ASU 2016-13 will necessitate that the Company establish an allowance for expected credit losses for certain debt securities and other financial assets. While the Company is currently unable to reasonably estimate the impact of adopting ASU 2016-13, we expect that the impact of adoption will be significantly influenced by the composition, characteristics and quality of our loan and securities portfolios as well as the prevailing economic conditions and forecasts as of the adoption date. The Company expects to adopt the standard in the first quarter of 2020.

Securities (Tables)

Securities (Tables)	6 Months Ended
	Jun. 30, 2019
Investments Debt And Equity Securities [Abstract]
Summary of Amortized Cost and Estimated Fair Values of Debt Securities Held for Investment	The following table summarizes the amortized cost and estimated fair values of debt securities held for investment: Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value June 30, 2019 (Dollars in thousands) Mortgage backed securities (1) $ 112 $ 6 $ — $ 118 States and political subdivisions 1,385 1 (1 ) 1,385 Other securities 500 — — 500 Total $ 1,997 $ 7 $ (1 ) $ 2,003 December 31, 2018 Mortgage backed securities (1) $ 133 $ 5 $ — $ 138 States and political subdivisions 795 — — 795 Other securities 500 — — 500 Total $ 1,428 $ 5 $ — $ 1,433
Summary of Amortized Cost and Estimated Fair Values of Debt Securities Available for Sale	The following table summarizes the amortized cost and estimated fair values of debt securities available for sale: Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value June 30, 2019 (Dollars in thousands) U.S. treasuries $ 353,618 $ 5,371 $ (355 ) $ 358,634 U.S. federal agencies 26,169 12 (26 ) 26,155 Mortgage backed securities (1) 15,646 138 (565 ) 15,219 States and political subdivisions 22,820 335 (6 ) 23,149 Total $ 418,253 $ 5,856 $ (952 ) $ 423,157 December 31, 2018 U.S. treasuries $ 699,882 $ 1,108 $ (3,524 ) $ 697,466 U.S. federal agencies 30,079 — (160 ) 29,919 Mortgage backed securities (1) 16,367 114 (573 ) 15,908 States and political subdivisions 27,246 277 (112 ) 27,411 Total $ 773,574 $ 1,499 $ (4,369 ) $ 770,704 (1) Primarily consists of FHLMC, FNMA, GNMA and mortgage backed securities through U.S. agencies.
Maturity of Debt Securities	The maturities of debt 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. June 30, 2019 December 31, 2018 Amortized Cost Estimated Fair Value Amortized Cost Estimated Fair Value (Dollars in thousands) Held for Investment Contractual maturity of debt securities: Within one year $ 300 $ 301 $ 495 $ 495 After one year but within five years 1,146 1,147 369 370 After five years but within ten years 549 553 562 565 After ten years 2 2 2 3 Total $ 1,997 $ 2,003 $ 1,428 $ 1,433 Available for Sale Contractual maturity of debt securities: Within one year $ 103,395 $ 103,084 $ 411,256 $ 410,327 After one year but within five years 270,900 276,333 313,416 311,924 After five years but within ten years 6,355 6,606 7,524 7,685 After ten years 37,603 37,134 41,378 40,768 Total debt securities $ 418,253 $ 423,157 $ 773,574 $ 770,704
Company's Book Value of Pledged Debt 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: June 30, 2019 December 31, 2018 (Dollars Book value of pledged securities $ 402,756 $ 472,053

Loans and Allowance for Loan _2

Loans and Allowance for Loan Losses (Tables)	6 Months Ended
	Jun. 30, 2019
Receivables [Abstract]
Schedule of Loans Outstanding by Category	The following is a schedule of loans outstanding by category: June 30, 2019 December 31, 2018 Amount Percent Amount Percent (Dollars in thousands) Commercial and financial: Commercial and industrial $ 1,062,527 20.86 % $ 1,032,787 20.76 % Oil & gas production and equipment 122,268 2.40 94,729 1.90 Agriculture 130,957 2.57 136,313 2.74 State and political subdivisions: Taxable 74,596 1.46 76,211 1.53 Tax-exempt 51,114 1.00 48,415 0.97 Real estate: Construction 450,525 8.84 451,224 9.07 Farmland 227,635 4.47 219,241 4.41 One to four family residences 990,377 19.44 979,170 19.68 Multifamily residential properties 68,743 1.35 65,949 1.33 Commercial 1,525,064 29.94 1,506,937 30.28 Consumer 345,783 6.79 328,069 6.59 Other (not classified above) 44,814 0.88 36,931 0.74 Total loans $ 5,094,403 100.00 % $ 4,975,976 100.00 %
Summary of Nonperforming and Restructured Assets	The following is a summary of nonperforming and restructured assets: June 30, December 31, 2019 2018 (Dollars in thousands) Past due 90 days or more and still accruing $ 2,663 $ 1,916 Nonaccrual 17,998 22,603 Restructured 16,486 13,188 Total nonperforming and restructured loans 37,147 37,707 Other real estate owned and repossessed assets 7,004 6,873 Total nonperforming and restructured assets $ 44,151 $ 44,580
Summary of Amounts Included in Nonaccrual Loans Segregated by Class of Loans	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. June 30, 2019 December 31, 2018 (Dollars in thousands) Real estate: Non-residential real estate owner occupied $ 1,127 $ 838 Non-residential real estate other 674 187 Residential real estate permanent mortgage 1,585 954 Residential real estate all other 5,327 5,488 Commercial and financial: Non-consumer non-real estate 2,958 5,682 Consumer non-real estate 394 437 Other loans 272 490 Acquired loans 5,661 8,527 Total $ 17,998 $ 22,603
Age Analysis of Past Due Loans Segregated by Class of Loans	Loans are considered past due if the required principal and interest payments have not been received as of the date such payments were due. The following table presents an age analysis of past due loans, segregated by class of loans: Age Analysis of Past Due Loans 30-59 Days Past Due 60-89 Days Past Due 90 Days and Greater Total Past Due Loans Current Loans Total Loans Accruing Loans 90 Days or More Past Due (Dollars in thousands) As of June 30, 2019 Real estate: Non-residential real estate owner occupied $ 4,203 $ 852 $ 536 $ 5,591 $ 649,600 $ 655,191 $ 117 Non-residential real estate other 1,088 — 325 1,413 1,179,092 1,180,505 177 Residential real estate permanent mortgage 2,583 760 986 4,329 330,046 334,375 384 Residential real estate all other 2,218 340 4,908 7,466 849,448 856,914 150 Commercial and financial: Non-consumer non-real estate 1,652 918 2,099 4,669 1,360,458 1,365,127 454 Consumer non-real estate 1,846 540 470 2,856 342,684 345,540 232 Other loans 220 1,083 183 1,486 142,387 143,873 183 Acquired loans 2,583 882 3,592 7,057 205,821 212,878 966 Total $ 16,393 $ 5,375 $ 13,099 $ 34,867 $ 5,059,536 $ 5,094,403 $ 2,663 As of December 31, 2018 Real estate: Non-residential real estate owner occupied $ 5,114 $ 810 $ 43 $ 5,967 $ 620,654 $ 626,621 $ — Non-residential real estate other 2,772 32 114 2,918 1,143,210 1,146,128 — Residential real estate permanent mortgage 2,448 653 693 3,794 324,908 328,702 430 Residential real estate all other 1,728 292 2,799 4,819 822,685 827,504 612 Commercial and financial: Non-consumer non-real estate 3,620 702 833 5,155 1,278,499 1,283,654 282 Consumer non-real estate 1,991 565 559 3,115 323,747 326,862 325 Other loans 322 158 178 658 141,251 141,909 — Acquired loans 5,240 1,669 4,936 11,845 282,751 294,596 267 Total $ 23,235 $ 4,881 $ 10,155 $ 38,271 $ 4,937,705 $ 4,975,976 $ 1,916
Impaired Loans Segregated by Class of Loans	The following table presents impaired loans, segregated by class of loans. During the period ended June 30, 2019 and June 30, 2018, no material amount of interest income was recognized on impaired loans subsequent to their classification as impaired. Impaired Loans Unpaid Principal Balance Recorded Investment with Allowance Related Allowance Average Recorded Investment (Dollars in thousands) As of June 30, 2019 Real estate: Non-residential real estate owner occupied $ 8,051 $ 7,933 $ 239 $ 7,662 Non-residential real estate other 1,687 1,422 190 1,615 Residential real estate permanent mortgage 2,427 2,151 183 1,964 Residential real estate all other 6,629 6,350 3,081 6,529 Commercial and financial: Non-consumer non-real estate 18,389 10,842 931 10,944 Consumer non-real estate 781 672 149 691 Other loans 659 455 17 322 Acquired loans 9,553 7,244 2 8,863 Total $ 48,176 $ 37,069 $ 4,792 $ 38,590 As of December 31, 2018 Real estate: Non-residential real estate owner occupied $ 7,126 $ 6,933 $ 202 $ 7,739 Non-residential real estate other 949 757 50 6,057 Residential real estate permanent mortgage 1,789 1,545 127 1,650 Residential real estate all other 7,177 6,862 2,433 7,154 Commercial and financial: Non-consumer non-real estate 18,507 10,977 881 12,140 Consumer non-real estate 928 829 131 846 Other loans 710 490 35 481 Acquired loans 12,846 9,864 2 11,050 Total $ 50,032 $ 38,257 $ 3,861 $ 47,117
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 June 30, 2019 Real estate: Non-residential real estate owner occupied $ 457,211 $ 171,239 $ 25,491 $ 1,250 $ — $ 655,191 Non-residential real estate other 950,058 202,397 27,291 759 — 1,180,505 Residential real estate permanent mortgage 281,593 43,479 7,242 2,061 — 334,375 Residential real estate all other 669,269 167,518 14,375 5,752 — 856,914 Commercial and financial: Non-consumer non-real estate 1,077,429 252,175 33,630 1,893 — 1,365,127 Consumer non-real estate 320,278 21,955 2,707 565 35 345,540 Other loans 138,414 4,160 1,289 10 — 143,873 Acquired loans 124,437 71,790 9,751 6,603 297 212,878 Total $ 4,018,689 $ 934,713 $ 121,776 $ 18,893 $ 332 $ 5,094,403 As of December 31, 2018 Real estate: Non-residential real estate owner occupied $ 451,059 $ 157,715 $ 16,949 $ 898 $ — $ 626,621 Non-residential real estate other 932,454 188,341 25,146 187 — 1,146,128 Residential real estate permanent mortgage 279,870 39,806 7,401 1,625 — 328,702 Residential real estate all other 644,217 162,003 15,232 6,052 — 827,504 Commercial and financial: Non-consumer non-real estate 1,000,089 264,134 15,128 4,303 — 1,283,654 Consumer non-real estate 302,217 21,600 2,255 790 — 326,862 Other loans 136,132 5,542 116 119 — 141,909 Acquired loans 156,008 109,075 20,884 8,284 345 294,596 Total $ 3,902,046 $ 948,216 $ 103,111 $ 22,258 $ 345 $ 4,975,976
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 categories. ALL Balance at beginning of period Charge- offs Recoveries Net charge-offs Provisions charged to operations Balance at end of period (Dollars in thousands) Three Months Ended June 30, 2019 Real estate: Non-residential real estate owner occupied $ 6,655 $ (3 ) $ — $ (3 ) $ 235 $ 6,887 Non-residential real estate other 11,362 (16 ) 1 (15 ) (60 ) 11,287 Residential real estate permanent mortgage 3,261 (4 ) 4 — 64 3,325 Residential real estate all other 11,046 (143 ) 25 (118 ) 793 11,721 Commercial and financial: Non-consumer non-real estate 14,409 (87 ) 85 (2 ) 825 15,232 Consumer non-real estate 3,072 (162 ) 38 (124 ) 286 3,234 Other loans 2,408 — 43 43 (2 ) 2,449 Acquired loans 702 (170 ) 149 (21 ) 292 973 Total $ 52,915 $ (585 ) $ 345 $ (240 ) $ 2,433 $ 55,108 Six Months Ended June 30, 2019 Real estate: Non-residential real estate owner occupied $ 6,328 $ (9 ) $ 1 $ (8 ) $ 567 $ 6,887 Non-residential real estate other 11,027 (22 ) 1 (21 ) 281 11,287 Residential real estate permanent mortgage 3,261 (67 ) 9 (58 ) 122 3,325 Residential real estate all other 10,673 (195 ) 27 (168 ) 1,216 11,721 Commercial and financial: Non-consumer non-real estate 13,151 (157 ) 152 (5 ) 2,086 15,232 Consumer non-real estate 3,065 (282 ) 109 (173 ) 342 3,234 Other loans 2,423 — 78 78 (52 ) 2,449 Acquired loans 1,461 (196 ) 153 (43 ) (445 ) 973 Total $ 51,389 $ (928 ) $ 530 $ (398 ) $ 4,117 $ 55,108 ALL Balance at beginning of period Charge- offs Recoveries Net charge-offs Provisions charged to operations Balance at end of period (Dollars in thousands) Three Months Ended June 30, 2018 Real estate: Non-residential real estate owner occupied $ 6,650 $ — $ — $ — $ (224 ) $ 6,426 Non-residential real estate other 10,548 — — — 157 10,705 Residential real estate permanent mortgage 3,281 (6 ) 23 17 9 3,307 Residential real estate all other 9,831 (151 ) 3 (148 ) 440 10,123 Commercial and financial: Non-consumer non-real estate 14,785 (153 ) 10 (143 ) 427 15,069 Consumer non-real estate 2,699 (194 ) 44 (150 ) 290 2,839 Other loans 2,336 (2 ) 12 10 (18 ) 2,328 Acquired loans 1,420 (166 ) 5 (161 ) 144 1,403 Total $ 51,550 $ (672 ) $ 97 $ (575 ) $ 1,225 $ 52,200 Six Months Ended June 30, 2018 Real estate: Non-residential real estate owner occupied $ 6,195 $ (19 ) $ 1 $ (18 ) $ 249 $ 6,426 Non-residential real estate other 10,519 (1 ) 39 38 148 10,705 Residential real estate permanent mortgage 3,226 (62 ) 26 (36 ) 117 3,307 Residential real estate all other 9,672 (241 ) 6 (235 ) 686 10,123 Commercial and financial: Non-consumer non-real estate 15,334 (309 ) 23 (286 ) 21 15,069 Consumer non-real estate 2,793 (444 ) 124 (320 ) 366 2,839 Other loans 2,481 (2 ) 24 22 (175 ) 2,328 Acquired loans 1,446 (193 ) 23 (170 ) 127 1,403 Total $ 51,666 $ (1,271 ) $ 266 $ (1,005 ) $ 1,539 $ 52,200
Allowance for Loan Losses Outstanding by Impairment Methodology	The following table details the amount of ALL by class of loans for the period presented, detailed on the basis of the impairment methodology used by the Company. ALL June 30, 2019 December 31, 2018 Individually evaluated for impairment Collectively evaluated for impairment Individually evaluated for impairment Collectively evaluated for impairment (Dollars in thousands) Real estate: Non-residential real estate owner occupied $ 1,003 $ 5,884 $ 669 $ 5,659 Non-residential real estate other 1,055 10,232 1,119 9,908 Residential real estate permanent mortgage 508 2,817 505 2,756 Residential real estate all other 4,189 7,532 3,413 7,260 Commercial and financial: Non-consumer non-real estate 3,679 11,553 2,114 11,037 Consumer non-real estate 427 2,807 374 2,691 Other loans 10 2,439 65 2,358 Acquired loans — 973 — 1,461 Total $ 10,871 $ 44,237 $ 8,259 $ 43,130
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 June 30, 2019 December 31, 2018 Individually evaluated for impairment Collectively evaluated for impairment Loans acquired with deteriorated credit quality Individually evaluated for impairment Collectively evaluated for impairment Loans acquired with deteriorated credit quality (Dollars in thousands) Real estate: Non-residential real estate owner occupied $ 26,741 $ 628,450 $ — $ 17,846 $ 608,775 $ — Non-residential real estate other 28,050 1,152,455 — 25,333 1,120,795 — Residential real estate permanent mortgage 9,303 325,072 — 9,026 319,676 — Residential real estate all other 20,127 836,787 — 21,285 806,219 — Commercial and financial: Non-consumer non-real estate 35,523 1,329,604 — 19,432 1,264,222 — Consumer non-real estate 3,304 342,236 — 3,093 323,769 — Other loans 10 143,863 — 209 141,700 — Acquired loans 14,399 196,226 2,253 22,132 265,084 7,380 Total $ 137,457 $ 4,954,693 $ 2,253 $ 118,356 $ 4,850,240 $ 7,380
Transfers from Loans and Premises and Equipment to Other Real Estate Owned and Repossessed Assets	Transfers from loans and premises and equipment to other real estate owned and repossessed assets are non-cash transactions, and are not included in the statements of cash flow. Such transfers during the periods presented, are summarized as follows: Six Months Ended June 30, 2019 2018 (Dollars in thousands) Other real estate owned $ 2,010 $ 1,123 Repossessed assets 627 550 Total $ 2,637 $ 1,673

Intangible Assets (Tables)

Intangible Assets (Tables)	6 Months Ended
	Jun. 30, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Summary of Intangible Assets	The following is a summary of intangible assets: Gross Carrying Amount Accumulated Amortization Net Carrying Amount (Dollars in thousands) As of June 30, 2019 Core deposit intangibles $ 25,907 $ (12,456 ) $ 13,451 Customer relationship intangibles 5,699 (4,289 ) 1,410 Mortgage servicing intangibles 388 (313 ) 75 Total $ 31,994 $ (17,058 ) $ 14,936 As of December 31, 2018 Core deposit intangibles $ 25,907 $ (11,113 ) $ 14,794 Customer relationship intangibles 5,699 (4,115 ) 1,584 Mortgage servicing intangibles 397 (305 ) 92 Total $ 32,003 $ (15,533 ) $ 16,470
Summary of Goodwill by Business Segment	The following is a summary of goodwill by business segment: Other Executive, Metropolitan Community Financial Operations Banks Banks Services & Support Consolidated (Dollars in thousands) Six months ended June 30, 2019 Balance at beginning and end of period $ 13,767 $ 59,894 $ 5,464 $ 624 $ 79,749

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Schedule of Maturity of Operating Lease Liabilities	Maturity of Operating Lease Liabilities June 30, 2019 (Dollars in thousands) 2019 (six months) $ 55 2020 829 2021 114 2022 1,542 2023 636 Thereafter 2,072 Operating Lease Liability $ 5,248
Scheduled of Minimum Future Contractual Rent To be Received Under The Remaining Non-Cancelable Term of Operating Leases	The following table presents the scheduled minimum future contractual rent to be received under the remaining non-cancelable term of the operating leases: June 30, 2019 (Dollars in thousands) 2019 (six months) $ 2,129 2020 2,681 2021 1,788 2022 1,141 2023 681 2024 75 Total Future Minimum Lease Payments $ 8,495

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2019
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: Wgtd. Avg. Wgtd. Avg. Remaining Aggregate Exercise Contractual Intrinsic Options Price Term Value (Dollars in thousands, except option data) Six Months Ended June 30, 2019 Outstanding at December 31, 2018 1,216,700 $ 28.48 Options granted 40,000 55.38 Options exercised (27,300 ) 22.37 Options canceled, forfeited, or expired (22,500 ) 51.83 Outstanding at June 30, 2019 1,206,900 29.07 9.20 Yrs $ 32,090 Exercisable at June 30, 2019 648,400 22.49 7.08 Yrs $ 21,506
Options Exercised Under Stock Option Plan	The following table has additional information regarding options exercised under both the BancFirst ISOP and the BancFirst Directors’ Stock Option Plan: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (Dollars in thousands) (Dollars in thousands) Total intrinsic value of options exercised $ 759 $ 967 $ 904 $ 3,827 Cash received from options exercised 455 411 611 1,644 Tax benefit realized from options exercised 193 246 230 975
Stock-based Employee Compensation Expense	The following table is a summary of the Company’s recorded stock-based compensation expense: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (Dollars in thousands) (Dollars in thousands) Stock-based compensation expense $ 367 $ 322 $ 541 $ 628 Tax benefit 94 82 138 160 Stock-based compensation expense, net of tax $ 273 $ 240 $ 403 $ 468
Unearned Stock-based Compensation Expense	The Company will continue to amortize the unearned stock-based compensation expense over the remaining vesting period of approximately seven years. The following table shows the unearned stock-based compensation expense: June 30, 2019 (Dollars in thousands) Unearned stock-based compensation expense $ 3,198
Assumptions Used for Computing Stock-Based Compensation Expense	The following table shows the assumptions used for computing stock-based compensation expense under the fair value method on options granted during the periods presented: Six Months Ended June 30, 2019 2018 Weighted average grant-date fair value per share of options granted $ 13.67 $ 13.98 Risk-free interest rate 2.62 to 2.76% 2.55 to 2.92% Dividend yield 2.00% 2.00% Stock price volatility 22.93 to 22.96% 23.05 to 23.29% Expected term 10 Yrs 10 Yrs
Summary of Accumulated Stock Units	A summary of the accumulated stock units is as follows: June 30, December 31, 2019 2018 Accumulated stock units 139,862 143,347 Average price $ 26.19 $ 24.91

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2019
Equity [Abstract]
Summary of Shares Repurchased Under Stock Purchase Program	The following table is a summary of the shares under the program: Six Months Ended June 30, 2019 2018 Number of shares repurchased — — Average price of shares repurchased $ — $ — Shares remaining to be repurchased 148,736 300,000
Required Capital Amounts and Company's Respective Ratios	The actual and required capital amounts and ratios are shown in the following table: Required To Be Well For Capital With Capitalized Under Adequacy Capital Conservation Prompt Corrective Actual Purposes Buffer Action Provisions Amount Ratio Amount Ratio Amount Ratio Amount Ratio (Dollars in thousands) As of June 30, 2019: Total Capital (to Risk Weighted Assets)- BancFirst Corporation $ 939,223 16.71% $ 449,674 8.00% $ 590,197 10.50% N/A N/A BancFirst 813,627 14.50% 448,824 8.00% 589,082 10.50% $ 561,030 10.00% Common Equity Tier 1 Capital (to Risk Weighted Assets)- BancFirst Corporation $ 858,115 15.27% $ 252,942 4.50% $ 393,465 7.00% N/A N/A BancFirst 738,519 13.16% 252,464 4.50% 392,721 7.00% $ 364,670 6.50% Tier 1 Capital (to Risk Weighted Assets)- BancFirst Corporation $ 884,115 15.73% $ 337,256 6.00% $ 477,779 8.50% N/A N/A BancFirst 758,519 13.52% 336,618 6.00% 476,876 8.50% $ 448,824 8.00% Tier 1 Capital (to Total Assets)- BancFirst Corporation $ 884,115 11.64% $ 303,864 4.00% N/A N/A N/A N/A BancFirst 758,519 10.01% 303,252 4.00% N/A N/A $ 379,065 5.00%

Net Income Per Common Share (Ta

Net Income Per Common Share (Tables)	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Basic and Diluted Net Income Per Common Share Based on Weighted-average Shares Outstanding	Basic and diluted net income per common share based on weighted-average shares outstanding are calculated as follows: Income (Numerator) Shares (Denominator) Per Share Amount (Dollars in thousands, except per share data) Three Months Ended June 30, 2019 Basic Income available to common stockholders $ 34,167 32,629,146 $ 1.04 Dilutive effect of stock options — 688,047 Diluted Income available to common stockholders plus assumed exercises of stock options $ 34,167 33,317,193 $ 1.02 Three Months Ended June 30, 2018 Basic Income available to common stockholders $ 30,586 32,716,350 $ 0.93 Dilutive effect of stock options — 742,207 Diluted Income available to common stockholders plus assumed exercises of stock options $ 30,586 33,458,557 $ 0.91 Six Months Ended June 30, 2019 Basic Income available to common stockholders $ 66,004 32,620,819 $ 2.02 Dilutive effect of stock options — 685,610 Diluted Income available to common stockholders plus assumed exercises of stock options $ 66,004 33,306,429 $ 1.98 Six Months Ended June 30, 2018 Basic Income available to common stockholders $ 60,206 32,645,693 $ 1.84 Dilutive effect of stock options — 744,269 Diluted Income available to common stockholders plus assumed exercises of stock options $ 60,206 33,389,962 $ 1.80
Options Excluded From Computation of Diluted Net Income Per Common Share	The following table shows the number of options that were excluded from the computation of diluted net income per common share for each period because the options were anti-dilutive for the period: Shares Three Months Ended June 30, 2019 158,500 Three Months Ended June 30, 2018 85,802 Six Months Ended June 30, 2019 169,301 Six Months Ended June 30, 2018 117,696

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2019
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 the periods presented, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value: Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Fair Value (Dollars in thousands) June 30, 2019 Securities available for sale: U.S. Treasury $ 358,634 $ — $ — $ 358,634 U.S. federal agencies — 26,155 — 26,155 Mortgage-backed securities — 2,164 13,055 15,219 States and political subdivisions — 23,149 — 23,149 Derivative assets — 19 — 19 Derivative liabilities — 17 — 17 December 31, 2018 Securities available for sale: U.S. Treasury $ 697,466 $ — $ — $ 697,466 U.S. federal agencies — 29,919 — 29,919 Mortgage-backed securities — 2,465 13,443 15,908 States and political subdivisions — 27,411 — 27,411 Derivative assets — 252 — 252 Derivative liabilities — 238 — 238
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 periods presented were as follows: Six Months Ended June 30, Twelve Months Ended December 31, 2019 2018 (Dollars in thousands) Balance at the beginning of the year $ 13,443 $ 14,467 Settlements (396 ) (1,037 ) Total unrealized (losses) gains 8 13 Balance at the end of the period $ 13,055 $ 13,443
Assets Measured at Fair Value on Nonrecurring Basis	The following table summarizes assets measured at fair value on a nonrecurring basis. The fair value represents end of period values, which approximate fair value measurements that occurred on various measurement dates throughout the period: Total Fair Value Level 3 (Dollars in thousands) As of and for the Year-to-date Period Ended June 30, 2019 Equity securities $ 9,099 Impaired loans (less specific allowance) 32,277 Repossessed assets 201 Other real estate owned 1,759 As of and for the Year-to-date Period Ended December 31, 2018 Equity securities $ 7,521 Impaired loans (less specific allowance) 34,396 Repossessed assets 183 Other real estate owned 4,683
Estimated Fair Values of 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: June 30, December 31, 2019 2018 Carrying Amount Fair Value Carrying Amount Fair Value (Dollars in thousands) FINANCIAL ASSETS Level 2 inputs: Cash and cash equivalents $ 1,704,438 $ 1,704,438 $ 1,424,255 $ 1,424,255 Securities held for investment 1,497 1,503 928 933 Loans held for sale 10,899 10,899 8,174 8,174 Level 3 inputs: Securities held for investment 500 500 500 500 Loans, net of allowance for loan losses 5,039,295 5,052,074 4,924,587 4,901,159 FINANCIAL LIABILITIES Level 2 inputs: Deposits 6,613,613 6,729,518 6,605,495 6,713,542 Short-term borrowings 1,000 1,000 1,675 1,675 Junior subordinated debentures 26,804 28,777 26,804 29,549 OFF-BALANCE SHEET FINANCIAL INSTRUMENTS Loan commitments 2,277 2,158 Letters of credit 414 421

Segment Information (Tables)

Segment Information (Tables)	6 Months Ended
	Jun. 30, 2019
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 Banks Community Banks Other Financial Services Executive, Operations & Support Eliminations Consolidated (Dollars in thousands) Three Months Ended June 30, 2019 Net interest income $ 21,438 $ 44,775 $ 1,411 $ 1,168 $ — $ 68,792 Noninterest income 4,635 16,243 10,105 37,917 (34,823 ) 34,077 Income before taxes 14,866 30,041 5,572 27,590 (34,241 ) 43,828 Three Months Ended June 30, 2018 Net interest income $ 21,084 $ 42,068 $ 1,358 $ 370 $ — $ 64,880 Noninterest income 4,184 14,832 8,896 33,609 (31,084 ) 30,437 Income before taxes 14,883 27,942 4,028 23,622 (30,639 ) 39,836 Six Months Ended June 30, 2019 Net interest income $ 42,791 $ 88,182 $ 2,582 $ 2,140 $ — $ 135,695 Noninterest income 8,844 31,128 19,978 73,438 (67,310 ) 66,078 Income before taxes 30,235 58,086 10,071 52,613 (66,163 ) 84,842 Six Months Ended June 30, 2018 Net interest income $ 41,388 $ 83,450 $ 2,833 $ 244 $ — $ 127,915 Noninterest income 8,125 28,785 18,520 65,803 (60,686 ) 60,547 Income before taxes 29,619 54,290 9,071 43,537 (59,740 ) 76,777 Total Assets: June 30, 2019 $ 2,795,525 $ 4,981,139 $ 45,972 $ 883,471 $ (1,064,086 ) $ 7,642,021 December 31, 2018 2,743,876 4,892,946 84,706 861,782 (1,009,052 ) 7,574,258

Description of Business and S_3

Description of Business and Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Millions	Jun. 30, 2019	Jan. 01, 2019
Accounting Policies [Abstract]
Right-of-use lease assets	$ 5.3	$ 4.3
Lease liabilities	$ 5.2	$ 4.3

Recent Developments Including M

Recent Developments Including Mergers and Acquisitions - Additional Information (Detail) $ in Thousands	Apr. 23, 2019USD ($)	Dec. 14, 2018USD ($)ParkingSpaces	Aug. 31, 2018USD ($)ft²Floor	Jan. 11, 2018USD ($)CommunityLocation	Jun. 30, 2019USD ($)	Dec. 31, 2018USD ($)
Business Combination Separately Recognized Transactions [Line Items]
Goodwill					$ 79,749	$ 79,749
Number of additional banking communities | Community				5
Pegasus Bank [Member]
Business Combination Separately Recognized Transactions [Line Items]
Business acquisition, date of agreement	Apr. 23, 2019
Contract price	$ 123,500
Total assets acquired						639,100
Loans						367,400
Deposits						$ 595,300
Cotter Ranch Tower [Member] | BFTower LLC [Member]
Business Combination Separately Recognized Transactions [Line Items]
Contract price			$ 21,000
Number of square feet | ft²			507,000
Number of floors | Floor			36
Date of acquisition			Aug. 31, 2018
Percentage of property leased			55.00%
Percentage of occupancy			35.00%
Percentage of occupancy including leased space			90.00%
Renovations completion year			2020
Renovations cost			$ 70,000
Tenant improvements			$ 12,000
Number of square feet to be occupied | ft²			165,000
Cotter Ranch Tower [Member] | BFTower LLC [Member] | SFPG, LLC [Member]
Business Combination Separately Recognized Transactions [Line Items]
Ownership interest acquired		42.60%
Space of parking garage | ParkingSpaces		1,568
Payment to acquire ownership interest		$ 9,800
First Bank & Trust Company [Member]
Business Combination Separately Recognized Transactions [Line Items]
Date of acquisition				Jan. 11, 2018
Total assets acquired				$ 290,000
Loans				247,000
Deposits				251,000
Intangibles assets, net				6,300
Goodwill				$ 19,100
First Bank of Chandler [Member]
Business Combination Separately Recognized Transactions [Line Items]
Date of acquisition				Jan. 11, 2018
Total assets acquired				$ 88,000
Loans				66,000
Deposits				79,000
Intangibles assets, net				2,200
Goodwill				$ 6,600
Number of locations acquired | Location				2

Securities - Summary of Amortiz

Securities - Summary of Amortized Cost and Estimated Fair Values of Debt Securities Held for Investment (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 1,997	$ 1,428
Gross Unrealized Gains	7	5
Gross Unrealized Losses	(1)
Estimated Fair Value	2,003	1,433
Mortgage Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	112	133
Gross Unrealized Gains	6	5
Estimated Fair Value	118	138
States and Political Subdivisions [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	1,385	795
Gross Unrealized Gains	1
Gross Unrealized Losses	(1)
Estimated Fair Value	1,385	795
Other Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	500	500
Estimated Fair Value	$ 500	$ 500

Securities - Summary of Amort_2

Securities - Summary of Amortized Cost and Estimated Fair Values of Debt Securities Available for Sale (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 418,253	$ 773,574
Gross Unrealized Gains	5,856	1,499
Gross Unrealized Losses	(952)	(4,369)
Estimated Fair Value	423,157	770,704
U.S. Treasuries [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	353,618	699,882
Gross Unrealized Gains	5,371	1,108
Gross Unrealized Losses	(355)	(3,524)
Estimated Fair Value	358,634	697,466
U.S. Federal Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	26,169	30,079
Gross Unrealized Gains	12
Gross Unrealized Losses	(26)	(160)
Estimated Fair Value	26,155	29,919
Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	15,646	16,367
Gross Unrealized Gains	138	114
Gross Unrealized Losses	(565)	(573)
Estimated Fair Value	15,219	15,908
States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	22,820	27,246
Gross Unrealized Gains	335	277
Gross Unrealized Losses	(6)	(112)
Estimated Fair Value	$ 23,149	$ 27,411

Securities - Maturity of Debt S

Securities - Maturity of Debt Securities (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Held for Investment, Contractual maturity of debt securities, Amortized Cost
Amortized cost, Within one year	$ 300	$ 495
Amortized cost, After one year but within five years	1,146	369
Amortized cost, After five years but within ten years	549	562
Amortized cost, After ten years	2	2
Amortized Cost	1,997	1,428
Available for sale, Contractual maturity of debt securities, Amortized Cost
Amortized Cost, Within one year	103,395	411,256
Amortized Cost, After one year but within five years	270,900	313,416
Amortized Cost, After five years but within ten years	6,355	7,524
Amortized Cost, After ten years	37,603	41,378
Amortized Cost	418,253	773,574
Held for Investment, Contractual maturity of debt securities, Estimated Fair Value
Estimated Fair Value, Within one year	301	495
Estimated Fair Value, After one year but within five years	1,147	370
Estimated Fair Value, After five years but within ten years	553	565
Estimated Fair Value, After ten years	2	3
Estimated Fair Value	2,003	1,433
Available for sale, Contractual maturity of debt securities, Estimated Fair Value
Estimated Fair Value, Within one year	103,084	410,327
Estimated Fair Value, After one year but within five years	276,333	311,924
Estimated Fair Value, After five years but within ten years	6,606	7,685
Estimated Fair Value, After ten years	37,134	40,768
Total debt securities	$ 423,157	$ 770,704

Securities - Company's Book Val

Securities - Company's Book Value of Pledged Debt Securities (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Pledged Financial Instruments Not Separately Reported Securities Pledged By Type Of Security [Abstract]
Book value of pledged securities	$ 402,756	$ 472,053

Loans and Allowance for Loan _3

Loans and Allowance for Loan Losses - Schedule of Loans Outstanding by Category (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 5,094,403	$ 4,975,976
Percent	100.00%	100.00%
Taxable [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 74,596	$ 76,211
Percent	1.46%	1.53%
Tax-exempt [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 51,114	$ 48,415
Percent	1.00%	0.97%
Commercial and Financial [Member] | Commercial and Industrial [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 1,062,527	$ 1,032,787
Percent	20.86%	20.76%
Commercial and Financial [Member] | Oil & Gas Production And Equipment [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 122,268	$ 94,729
Percent	2.40%	1.90%
Commercial and Financial [Member] | Agriculture [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 130,957	$ 136,313
Percent	2.57%	2.74%
Real Estate [Member] | Construction [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 450,525	$ 451,224
Percent	8.84%	9.07%
Real Estate [Member] | Farmland [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 227,635	$ 219,241
Percent	4.47%	4.41%
Real Estate [Member] | One to Four Family Residences [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 990,377	$ 979,170
Percent	19.44%	19.68%
Real Estate [Member] | Multifamily Residential Properties [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 68,743	$ 65,949
Percent	1.35%	1.33%
Real Estate [Member] | Commercial [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 1,525,064	$ 1,506,937
Percent	29.94%	30.28%
Consumer [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 345,783	$ 328,069
Percent	6.79%	6.59%
Other (Not Classified Above) [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 44,814	$ 36,931
Percent	0.88%	0.74%

Loans and Allowance for Loan _4

Loans and Allowance for Loan Losses - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 5,094,403,000		$ 4,975,976,000
Percentage of loans secured by real estate	64.00%
Interest income that would have been recognized	$ 1,000,000	$ 1,100,000
Interest income recognized on impaired loans	0	$ 0
Commercial and Industrial [Member] | Ancillary Services [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 74,000,000		$ 60,000,000

Loans and Allowance for Loan _5

Loans and Allowance for Loan Losses - Summary of Nonperforming and Restructured Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Summary Of Nonperforming And Restructured Assets [Abstract]
Past due 90 days or more and still accruing	$ 2,663	$ 1,916
Nonaccrual	17,998	22,603
Restructured	16,486	13,188
Total nonperforming and restructured loans	37,147	37,707
Other real estate owned and repossessed assets	7,004	6,873
Total nonperforming and restructured assets	$ 44,151	$ 44,580

Loans and Allowance for Loan _6

Loans and Allowance for Loan Losses - Summary of Amounts Included in Nonaccrual Loans Segregated by Class of Loans (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans, Total	$ 17,998	$ 22,603
Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans, Total	1,127	838
Real Estate [Member] | Non-residential Real Estate Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans, Total	674	187
Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans, Total	1,585	954
Real Estate [Member] | Residential Real Estate All Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans, Total	5,327	5,488
Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans, Total	2,958	5,682
Consumer Non-real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans, Total	394	437
Other Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans, Total	272	490
Acquired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans, Total	$ 5,661	$ 8,527

Loans and Allowance for Loan _7

Loans and Allowance for Loan Losses - Age Analysis of Past Due Loans Segregated by Class of Loans (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	$ 34,867	$ 38,271
Current Loans	5,059,536	4,937,705
Total Loans	5,094,403	4,975,976
Accruing Loans 90 Days or More Past Due	2,663	1,916
Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	5,591	5,967
Current Loans	649,600	620,654
Total Loans	655,191	626,621
Accruing Loans 90 Days or More Past Due	117
Real Estate [Member] | Non-residential Real Estate Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	1,413	2,918
Current Loans	1,179,092	1,143,210
Total Loans	1,180,505	1,146,128
Accruing Loans 90 Days or More Past Due	177
Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	4,329	3,794
Current Loans	330,046	324,908
Total Loans	334,375	328,702
Accruing Loans 90 Days or More Past Due	384	430
Real Estate [Member] | Residential Real Estate All Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	7,466	4,819
Current Loans	849,448	822,685
Total Loans	856,914	827,504
Accruing Loans 90 Days or More Past Due	150	612
Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	4,669	5,155
Current Loans	1,360,458	1,278,499
Total Loans	1,365,127	1,283,654
Accruing Loans 90 Days or More Past Due	454	282
Consumer Non-real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	2,856	3,115
Current Loans	342,684	323,747
Total Loans	345,540	326,862
Accruing Loans 90 Days or More Past Due	232	325
Other Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	1,486	658
Current Loans	142,387	141,251
Total Loans	143,873	141,909
Accruing Loans 90 Days or More Past Due	183
Acquired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	7,057	11,845
Current Loans	205,821	282,751
Total Loans	212,878	294,596
Accruing Loans 90 Days or More Past Due	966	267
30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	16,393	23,235
30 to 59 Days Past Due [Member] | Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	4,203	5,114
30 to 59 Days Past Due [Member] | Real Estate [Member] | Non-residential Real Estate Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	1,088	2,772
30 to 59 Days Past Due [Member] | Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	2,583	2,448
30 to 59 Days Past Due [Member] | Real Estate [Member] | Residential Real Estate All Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	2,218	1,728
30 to 59 Days Past Due [Member] | Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	1,652	3,620
30 to 59 Days Past Due [Member] | Consumer Non-real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	1,846	1,991
30 to 59 Days Past Due [Member] | Other Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	220	322
30 to 59 Days Past Due [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	2,583	5,240
60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	5,375	4,881
60 to 89 Days Past Due [Member] | Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	852	810
60 to 89 Days Past Due [Member] | Real Estate [Member] | Non-residential Real Estate Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans		32
60 to 89 Days Past Due [Member] | Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	760	653
60 to 89 Days Past Due [Member] | Real Estate [Member] | Residential Real Estate All Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	340	292
60 to 89 Days Past Due [Member] | Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	918	702
60 to 89 Days Past Due [Member] | Consumer Non-real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	540	565
60 to 89 Days Past Due [Member] | Other Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	1,083	158
60 to 89 Days Past Due [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	882	1,669
90 Days and Greater [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	13,099	10,155
90 Days and Greater [Member] | Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	536	43
90 Days and Greater [Member] | Real Estate [Member] | Non-residential Real Estate Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	325	114
90 Days and Greater [Member] | Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	986	693
90 Days and Greater [Member] | Real Estate [Member] | Residential Real Estate All Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	4,908	2,799
90 Days and Greater [Member] | Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	2,099	833
90 Days and Greater [Member] | Consumer Non-real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	470	559
90 Days and Greater [Member] | Other Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	183	178
90 Days and Greater [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	$ 3,592	$ 4,936

Loans and Allowance for Loan _8

Loans and Allowance for Loan Losses - Impaired Loans Segregated by Class of Loans (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	$ 48,176	$ 50,032
Recorded Investment with Allowance	37,069	38,257
Related Allowance	4,792	3,861
Average Recorded Investment	38,590	47,117
Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	8,051	7,126
Recorded Investment with Allowance	7,933	6,933
Related Allowance	239	202
Average Recorded Investment	7,662	7,739
Real Estate [Member] | Non-residential Real Estate Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	1,687	949
Recorded Investment with Allowance	1,422	757
Related Allowance	190	50
Average Recorded Investment	1,615	6,057
Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	2,427	1,789
Recorded Investment with Allowance	2,151	1,545
Related Allowance	183	127
Average Recorded Investment	1,964	1,650
Real Estate [Member] | Residential Real Estate All Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	6,629	7,177
Recorded Investment with Allowance	6,350	6,862
Related Allowance	3,081	2,433
Average Recorded Investment	6,529	7,154
Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	18,389	18,507
Recorded Investment with Allowance	10,842	10,977
Related Allowance	931	881
Average Recorded Investment	10,944	12,140
Consumer Non-real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	781	928
Recorded Investment with Allowance	672	829
Related Allowance	149	131
Average Recorded Investment	691	846
Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	659	710
Recorded Investment with Allowance	455	490
Related Allowance	17	35
Average Recorded Investment	322	481
Acquired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	9,553	12,846
Recorded Investment with Allowance	7,244	9,864
Related Allowance	2	2
Average Recorded Investment	$ 8,863	$ 11,050

Loans and Allowance for Loan _9

Loans and Allowance for Loan Losses - Internal Loan Grading by Class of Loans (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 5,094,403	$ 4,975,976
Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	655,191	626,621
Real Estate [Member] | Non-residential Real Estate Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	1,180,505	1,146,128
Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	334,375	328,702
Real Estate [Member] | Residential Real Estate All Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	856,914	827,504
Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	1,365,127	1,283,654
Consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	345,540	326,862
Other Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	143,873	141,909
Acquired Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	212,878	294,596
Grade 1 [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	4,018,689	3,902,046
Grade 1 [Member] | Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	457,211	451,059
Grade 1 [Member] | Real Estate [Member] | Non-residential Real Estate Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	950,058	932,454
Grade 1 [Member] | Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	281,593	279,870
Grade 1 [Member] | Real Estate [Member] | Residential Real Estate All Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	669,269	644,217
Grade 1 [Member] | Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	1,077,429	1,000,089
Grade 1 [Member] | Consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	320,278	302,217
Grade 1 [Member] | Other Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	138,414	136,132
Grade 1 [Member] | Acquired Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	124,437	156,008
Grade 2 [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	934,713	948,216
Grade 2 [Member] | Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	171,239	157,715
Grade 2 [Member] | Real Estate [Member] | Non-residential Real Estate Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	202,397	188,341
Grade 2 [Member] | Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	43,479	39,806
Grade 2 [Member] | Real Estate [Member] | Residential Real Estate All Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	167,518	162,003
Grade 2 [Member] | Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	252,175	264,134
Grade 2 [Member] | Consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	21,955	21,600
Grade 2 [Member] | Other Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	4,160	5,542
Grade 2 [Member] | Acquired Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	71,790	109,075
Grade 3 [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	121,776	103,111
Grade 3 [Member] | Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	25,491	16,949
Grade 3 [Member] | Real Estate [Member] | Non-residential Real Estate Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	27,291	25,146
Grade 3 [Member] | Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	7,242	7,401
Grade 3 [Member] | Real Estate [Member] | Residential Real Estate All Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	14,375	15,232
Grade 3 [Member] | Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	33,630	15,128
Grade 3 [Member] | Consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	2,707	2,255
Grade 3 [Member] | Other Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	1,289	116
Grade 3 [Member] | Acquired Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	9,751	20,884
Grade 4 [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	18,893	22,258
Grade 4 [Member] | Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	1,250	898
Grade 4 [Member] | Real Estate [Member] | Non-residential Real Estate Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	759	187
Grade 4 [Member] | Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	2,061	1,625
Grade 4 [Member] | Real Estate [Member] | Residential Real Estate All Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	5,752	6,052
Grade 4 [Member] | Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	1,893	4,303
Grade 4 [Member] | Consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	565	790
Grade 4 [Member] | Other Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	10	119
Grade 4 [Member] | Acquired Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	6,603	8,284
Grade 5 [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	332	345
Grade 5 [Member] | Consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	35
Grade 5 [Member] | Acquired Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 297	$ 345

Loans and Allowance for Loan_10

Loans and Allowance for Loan Losses - Activity in ALL by Class of Loans (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of period	$ 52,915	$ 51,550	$ 51,389	$ 51,666
Charge- offs	(585)	(672)	(928)	(1,271)
Recoveries	345	97	530	266
Net charge- offs	(240)	(575)	(398)	(1,005)
Provisions charged to operations	2,433	1,225	4,117	1,539
Balance at end of period	55,108	52,200	55,108	52,200
Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of period	6,655	6,650	6,328	6,195
Charge- offs	(3)		(9)	(19)
Recoveries			1	1
Net charge- offs	(3)		(8)	(18)
Provisions charged to operations	235	(224)	567	249
Balance at end of period	6,887	6,426	6,887	6,426
Real Estate [Member] | Non-residential Real Estate Other [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of period	11,362	10,548	11,027	10,519
Charge- offs	(16)		(22)	(1)
Recoveries	1		1	39
Net charge- offs	(15)		(21)	38
Provisions charged to operations	(60)	157	281	148
Balance at end of period	11,287	10,705	11,287	10,705
Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of period	3,261	3,281	3,261	3,226
Charge- offs	(4)	(6)	(67)	(62)
Recoveries	4	23	9	26
Net charge- offs		17	(58)	(36)
Provisions charged to operations	64	9	122	117
Balance at end of period	3,325	3,307	3,325	3,307
Real Estate [Member] | Residential Real Estate All Other [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of period	11,046	9,831	10,673	9,672
Charge- offs	(143)	(151)	(195)	(241)
Recoveries	25	3	27	6
Net charge- offs	(118)	(148)	(168)	(235)
Provisions charged to operations	793	440	1,216	686
Balance at end of period	11,721	10,123	11,721	10,123
Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of period	14,409	14,785	13,151	15,334
Charge- offs	(87)	(153)	(157)	(309)
Recoveries	85	10	152	23
Net charge- offs	(2)	(143)	(5)	(286)
Provisions charged to operations	825	427	2,086	21
Balance at end of period	15,232	15,069	15,232	15,069
Consumer Non-real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of period	3,072	2,699	3,065	2,793
Charge- offs	(162)	(194)	(282)	(444)
Recoveries	38	44	109	124
Net charge- offs	(124)	(150)	(173)	(320)
Provisions charged to operations	286	290	342	366
Balance at end of period	3,234	2,839	3,234	2,839
Other Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of period	2,408	2,336	2,423	2,481
Charge- offs		(2)		(2)
Recoveries	43	12	78	24
Net charge- offs	43	10	78	22
Provisions charged to operations	(2)	(18)	(52)	(175)
Balance at end of period	2,449	2,328	2,449	2,328
Acquired Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of period	702	1,420	1,461	1,446
Charge- offs	(170)	(166)	(196)	(193)
Recoveries	149	5	153	23
Net charge- offs	(21)	(161)	(43)	(170)
Provisions charged to operations	292	144	(445)	127
Balance at end of period	$ 973	$ 1,403	$ 973	$ 1,403

Loans and Allowance for Loan_11

Loans and Allowance for Loan Losses - Allowance for Loan Losses Outstanding by Impairment Methodology (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	$ 10,871	$ 8,259
Collectively evaluated for impairment	44,237	43,130
Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	1,003	669
Collectively evaluated for impairment	5,884	5,659
Real Estate [Member] | Non-residential Real Estate Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	1,055	1,119
Collectively evaluated for impairment	10,232	9,908
Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	508	505
Collectively evaluated for impairment	2,817	2,756
Real Estate [Member] | Residential Real Estate All Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	4,189	3,413
Collectively evaluated for impairment	7,532	7,260
Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	3,679	2,114
Collectively evaluated for impairment	11,553	11,037
Consumer Non-real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	427	374
Collectively evaluated for impairment	2,807	2,691
Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	10	65
Collectively evaluated for impairment	2,439	2,358
Acquired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collectively evaluated for impairment	$ 973	$ 1,461

Loans and Allowance for Loan_12

Loans and Allowance for Loan Losses - Loans Outstanding by Impairment Methodology (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	$ 137,457	$ 118,356
Collectively evaluated for impairment	4,954,693	4,850,240
Loans Acquired with Deteriorated Credit Quality [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans acquired with deteriorated credit quality	2,253	7,380
Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	26,741	17,846
Collectively evaluated for impairment	628,450	608,775
Real Estate [Member] | Non-residential Real Estate Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	28,050	25,333
Collectively evaluated for impairment	1,152,455	1,120,795
Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	9,303	9,026
Collectively evaluated for impairment	325,072	319,676
Real Estate [Member] | Residential Real Estate All Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	20,127	21,285
Collectively evaluated for impairment	836,787	806,219
Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	35,523	19,432
Collectively evaluated for impairment	1,329,604	1,264,222
Consumer Non-real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	3,304	3,093
Collectively evaluated for impairment	342,236	323,769
Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	10	209
Collectively evaluated for impairment	143,863	141,700
Acquired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	14,399	22,132
Collectively evaluated for impairment	196,226	265,084
Acquired Loans [Member] | Loans Acquired with Deteriorated Credit Quality [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans acquired with deteriorated credit quality	$ 2,253	$ 7,380

Loans and Allowance for Loan_13

Loans and Allowance for Loan Losses - Transfers from Loans and Premises and Equipment to Other Real Estate Owned and Repossessed Assets (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Noncash Investing And Financing Items [Abstract]
Other real estate owned	$ 2,010	$ 1,123
Repossessed assets	627	550
Total	$ 2,637	$ 1,673

Intangible Assets - Summary of

Intangible Assets - Summary of Intangible Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 31,994	$ 32,003
Accumulated Amortization	(17,058)	(15,533)
Net Carrying Amount	14,936	16,470
Core Deposit Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	25,907	25,907
Accumulated Amortization	(12,456)	(11,113)
Net Carrying Amount	13,451	14,794
Customer Relationship Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	5,699	5,699
Accumulated Amortization	(4,289)	(4,115)
Net Carrying Amount	1,410	1,584
Mortgage Servicing Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	388	397
Accumulated Amortization	(313)	(305)
Net Carrying Amount	$ 75	$ 92

Intangible Assets - Summary o_2

Intangible Assets - Summary of Goodwill by Business Segment (Detail) $ in Thousands	Jun. 30, 2019USD ($)
Goodwill [Line Items]
Balance at beginning of period	$ 79,749
Balance at end of period	79,749
Metropolitan Banks [Member]
Goodwill [Line Items]
Balance at beginning of period	13,767
Balance at end of period	13,767
Community Banks [Member]
Goodwill [Line Items]
Balance at beginning of period	59,894
Balance at end of period	59,894
Other Financial Services [Member]
Goodwill [Line Items]
Balance at beginning of period	5,464
Balance at end of period	5,464
Executive, Operations & Support [Member]
Goodwill [Line Items]
Balance at beginning of period	624
Balance at end of period	$ 624

Leases - Additional Information

Leases - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Jan. 01, 2019
Leases [Abstract]
Rent expense for operating leases	$ 343,000	$ 395,000	$ 700,000	$ 776,000
Right of use lease asset	$ 5,300,000		$ 5,300,000		$ 4,300,000
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	banf:AccruedInterestReceivableAndOtherAssetsMember		banf:AccruedInterestReceivableAndOtherAssetsMember
Operating lease liability	$ 5,200,000		$ 5,200,000		$ 4,300,000
Operating Lease, Liability, Statement of Financial Position [Extensible List]	banf:AccruedInterestPayableAndOtherLiabilitiesMember		banf:AccruedInterestPayableAndOtherLiabilitiesMember
Operating lease weighted-average remaining lease term	4 years 6 months		4 years 6 months
Operating lease weighted-average discount rate	3.60%		3.60%
Operating lease revenue	$ 1,500,000		$ 3,100,000

Leases - Schedule of Maturity o

Leases - Schedule of Maturity of Operating Lease Liabilities (Detail) $ in Thousands	Jun. 30, 2019USD ($)
Leases [Abstract]
2019 (six months)	$ 55
2020	829
2021	114
2022	1,542
2023	636
Thereafter	2,072
Operating Lease Liability	$ 5,248

Leases - Scheduled of Minimum F

Leases - Scheduled of Minimum Future Contractual Rent To be Received Under The Remaining Non-Cancelable Term of Operating Leases (Detail) $ in Thousands	Jun. 30, 2019USD ($)
Leases [Abstract]
2019 (six months)	$ 2,129
2020	2,681
2021	1,788
2022	1,141
2023	681
2024	75
Total Future Minimum Lease Payments	$ 8,495

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - shares	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Deferred board fees percentage for stock units accumulation	100.00%
Nonqualified Incentive Stock Option Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period in years	7 years
Nonqualified Incentive Stock Option Plan [Member] | Stock Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares to be issued under incentive stock option plan	6,484,530
Shares for future grants	350,000
Stock option plan termination date	Dec. 31, 2024
Option exercisable rate	25.00%
Option exercisable period	4 years
Options expire period	15 years
Share based compensation options exercisable period	2026
Vesting period in years, start	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
Nonqualified Incentive Stock Option Plan [Member] | Stock Option [Member] | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock price percentage to fair value at grant date	100.00%
Non-Employee Directors Stock Option Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares to be issued under incentive stock option plan	530,000
Shares for future grants	50,000
Stock option plan termination date	Dec. 31, 2024
Option exercisable rate	25.00%
Option exercisable period	1 year
Options expire period	15 years
Share based compensation options exercisable period	2023
Options vest and exercisable Description	The options vest and are exercisable beginning one year from the date of grant at the rate of 25% per year for four years
Number of options granted for non-employee director	10,000
Vesting period in years	4 years
Non-Employee Directors Stock Option Plan [Member] | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock price percentage to fair value at grant date	100.00%
Banc First Deferred Stock Compensation Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option plan termination date	Dec. 31, 2024
Number of shares authorized for issuance under deferred compensation plan	244,148
Number of shares of common stock distributed	8,362	3,891

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Activity Under Stock Option Plan (Detail) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2019USD ($)$ / sharesshares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Outstanding at beginning period - Options | shares	1,216,700
Options granted | shares	40,000
Options exercised | shares	(27,300)
Options canceled, forfeited, or expired | shares	(22,500)
Outstanding at ending period - Options | shares	1,206,900
Exercisable at ending period - Options | shares	648,400
Outstanding at beginning period - Wgtd. Avg. Exercise Price | $ / shares	$ 28.48
Options granted - Wgtd. Avg. Exercise Price | $ / shares	55.38
Options exercised - Wgtd. Avg. Exercise Price | $ / shares	22.37
Options cancelled, forfeited, or expired - Wgtd. Avg. Exercise Price | $ / shares	51.83
Outstanding at ending period - Wgtd. Avg. Exercise Price | $ / shares	29.07
Exercisable at ending period - Wgtd. Avg. Exercise Price | $ / shares	$ 22.49
Outstanding at ending period - Wgtd. Avg. Remaining Contractual Term, years	9 years 2 months 12 days
Exercisable at ending period - Wgtd. Avg. Remaining Contractual Term, years	7 years 29 days
Outstanding at ending period - Aggregate Intrinsic Value | $	$ 32,090
Exercisable at ending period - Aggregate Intrinsic Value | $	$ 21,506

Stock-Based Compensation - Opti

Stock-Based Compensation - Options Exercised Under Stock Option Plan (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Share Based Compensation Arrangement By Share Based Payment Award Options Additional Disclosures [Abstract]
Total intrinsic value of options exercised	$ 759	$ 967	$ 904	$ 3,827
Cash received from options exercised	455	411	611	1,644
Tax benefit realized from options exercised	$ 193	$ 246	$ 230	$ 975

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock-Based Employee Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Labor And Related Expense [Abstract]
Stock-based compensation expense	$ 367	$ 322	$ 541	$ 628
Tax benefit	94	82	138	160
Stock-based compensation expense, net of tax	$ 273	$ 240	$ 403	$ 468

Stock-Based Compensation - Unea

Stock-Based Compensation - Unearned Stock-based Compensation Expense (Detail) $ in Thousands	Jun. 30, 2019USD ($)
Share Based Compensation [Abstract]
Unearned stock-based compensation expense	$ 3,198

Stock-Based Compensation - Assu

Stock-Based Compensation - Assumptions Used for Computing Stock-Based Compensation Expense (Detail) - $ / shares	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions And Methodology [Abstract]
Weighted average grant-date fair value per share of options granted	$ 13.67	$ 13.98
Risk-free interest rate, minimum	2.62%	2.55%
Risk-free interest rate, maximum	2.76%	2.92%
Dividend yield	2.00%	2.00%
Stock price volatility, minimum	22.93%	23.05%
Stock price volatility, maximum	22.96%	23.29%
Expected term	10 years	10 years

Stock - Based Compensation - Su

Stock - Based Compensation - Summary of Accumulated Stock Units (Detail) - $ / shares	Jun. 30, 2019	Dec. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Accumulated stock units	139,862	143,347
Average price	$ 26.19	$ 24.91

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Shares Repurchased Under Stock Purchase Program (Detail) - shares	Jun. 30, 2019	Jun. 30, 2018
Summary Of Shares Repurchased Under Stock Purchase Program [Abstract]
Shares remaining to be repurchased	148,736	300,000

Stockholders' Equity - Required

Stockholders' Equity - Required Capital Amounts and Company's Respective Ratios (Detail) $ in Thousands	Jun. 30, 2019USD ($)
Parent Company [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital Amount	$ 939,223
Total Capital To Risk Weighted Assets Actual Ratio	16.71%
Capital Required For Capital Adequacy Amount	$ 449,674
Capital Required For Capital Adequacy to Risk Weighted Assets Ratio	8.00%
Capital With Capital Conservation Buffer Amount	$ 590,197
Capital With Capital Conservation To Risk Based Weighted Assets Buffer Ratio	10.50%
Common Equity Tier 1 Risk Based Capital Amount	$ 858,115
Common Equity Tier 1 Risk Based Capital To Risk Weighted Assets Ratio	15.27%
Common Equity Tier 1 Risk Based Capital Required For Capital Adequacy Amount	$ 252,942
Common Equity Tier 1 Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets Ratio	4.50%
Common Equity Tier 1 Risk Based Capital With Capital Conservation Buffer Amount	$ 393,465
Common Equity Tier 1 Risk Based Capital With Capital Conservation Buffer To Risk Weighted Assets Ratio	7.00%
Tier 1 Risk Based Capital Amount	$ 884,115
Tier 1 Risk Based Capital To Risk Weighted Assets Ratio	15.73%
Tier 1 Risk Based Capital Required For Capital Adequacy Amount	$ 337,256
Tier 1 Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets Ratio	6.00%
Tier 1 Risk Based Capital With Capital Conservation Buffer Amount	$ 477,779
Tier 1 Risk Based Capital With Capital Conservation Buffer To Risk Weighted Assets Ratio	8.50%
Tier 1 Capital Amount	$ 884,115
Tier 1 Capital To Average Assets Ratio	11.64%
Tier 1 Capital Required For Capital Adequacy Amount	$ 303,864
Tier 1 Capital Required For Capital Adequacy To Average Assets Ratio	4.00%
BancFirst [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital Amount	$ 813,627
Total Capital To Risk Weighted Assets Actual Ratio	14.50%
Capital Required For Capital Adequacy Amount	$ 448,824
Capital Required For Capital Adequacy to Risk Weighted Assets Ratio	8.00%
Capital With Capital Conservation Buffer Amount	$ 589,082
Capital With Capital Conservation To Risk Based Weighted Assets Buffer Ratio	10.50%
Capital Required To Be Well Capitalized Amount	$ 561,030
Capital Required To Be Well Capitalized To Risk Weighted Assets Ratio	10.00%
Common Equity Tier 1 Risk Based Capital Amount	$ 738,519
Common Equity Tier 1 Risk Based Capital To Risk Weighted Assets Ratio	13.16%
Common Equity Tier 1 Risk Based Capital Required For Capital Adequacy Amount	$ 252,464
Common Equity Tier 1 Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets Ratio	4.50%
Common Equity Tier 1 Risk Based Capital With Capital Conservation Buffer Amount	$ 392,721
Common Equity Tier 1 Risk Based Capital With Capital Conservation Buffer To Risk Weighted Assets Ratio	7.00%
Common Equity Tier 1 Risk Based Capital Required To Be Well Capitalized Amount	$ 364,670
Common Equity Tier 1 Risk Based Capital Required To Be Well Capitalized To Risk Weighted Assets Ratio	6.50%
Tier 1 Risk Based Capital Amount	$ 758,519
Tier 1 Risk Based Capital To Risk Weighted Assets Ratio	13.52%
Tier 1 Risk Based Capital Required For Capital Adequacy Amount	$ 336,618
Tier 1 Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets Ratio	6.00%
Tier 1 Risk Based Capital With Capital Conservation Buffer Amount	$ 476,876
Tier 1 Risk Based Capital With Capital Conservation Buffer To Risk Weighted Assets Ratio	8.50%
Tier 1 Risk Based Capital Required To Be Well Capitalized Amount	$ 448,824
Tier 1 Risk Based Capital Required To Be Well Capitalized To Risk Weighted Assets Ratio	8.00%
Tier 1 Capital Amount	$ 758,519
Tier 1 Capital To Average Assets Ratio	10.01%
Tier 1 Capital Required For Capital Adequacy Amount	$ 303,252
Tier 1 Capital Required For Capital Adequacy To Average Assets Ratio	4.00%
Tier 1 Capital Required To Be Well Capitalized Amount	$ 379,065
Tier 1 Capital Required To Be Well Capitalized To Average Assets Ratio	5.00%

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail)	Jun. 30, 2019USD ($)
Maximum [Member]
Stockholders Equity [Line Items]
Quantitative limit for trust preferred securities to be included in tier 1 capital	$ 15,000,000,000

Net Income Per Common Share - B

Net Income Per Common Share - Basic and Diluted Net Income Per Common Share Based on Weighted-average Shares Outstanding (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share Reconciliation [Abstract]
Income available to common stockholders	$ 34,167	$ 30,586	$ 66,004	$ 60,206
Income available to common stockholders plus assumed exercises of stock options	$ 34,167	$ 30,586	$ 66,004	$ 60,206
Income available to common stockholders - Shares	32,629,146	32,716,350	32,620,819	32,645,693
Dilutive effect of stock options - Shares	688,047	742,207	685,610	744,269
Income available to common stockholders plus assumed exercises of stock options - Shares	33,317,193	33,458,557	33,306,429	33,389,962
Income available to common stockholders - Per Share Amount	$ 1.04	$ 0.93	$ 2.02	$ 1.84
Income available to common stockholders plus assumed exercises of stock options - Per Share Amount	$ 1.02	$ 0.91	$ 1.98	$ 1.80

Net Income Per Common Share - O

Net Income Per Common Share - Options Excluded From Computation of Diluted Net Income Per Common Share (Detail) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Abstract]
Shares	158,500	85,802	169,301	117,696

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value of Financial Assets and Liabilities Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	$ 423,157	$ 770,704
Derivative assets	19	252
Derivative liabilities	17	238
U.S. Treasuries [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	358,634	697,466
U.S. Federal Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	26,155	29,919
Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	15,219	15,908
States and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	23,149	27,411
Level 1 Inputs [Member] | U.S. Treasuries [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	358,634	697,466
Level 2 Inputs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	19	252
Derivative liabilities	17	238
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	26,155	29,919
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	2,164	2,465
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	23,149	27,411
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	$ 13,055	$ 13,443

Fair Value Measurements - Chang

Fair Value Measurements - Changes in Level 3 Assets Measured at Estimated Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation Calculation Roll Forward
Balance at the beginning of the year	$ 13,443	$ 14,467
Settlements	(396)	(1,037)
Total unrealized (losses) gains	8	13
Balance at the end of the period	$ 13,055	$ 13,443

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended	12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Dec. 31, 2018
Debt Instrument Fair Value Disclosure [Abstract]
Transfer of securities between levels of fair value hierarchy	$ 0	$ 0
Days from origination after which mortgage loans are sold			30 days
Amount of non-financial assets (liabilities) measured at fair value on a recurring basis			$ 0	$ 0
Non-financial assets or liabilities for which no impairment was provided			$ 0	$ 0

Fair Value Measurements - Asset

Fair Value Measurements - Assets Measured at Fair Value on Nonrecurring Basis (Detail) - Level 3 [Member] - Nonrecurring [Member] - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Equity Securities [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Total Fair Value	$ 9,099	$ 7,521
Impaired Loans (Less Specific Allowance) [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Total Fair Value	32,277	34,396
Repossessed Assets [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Total Fair Value	201	183
Other Real Estate Owned [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Total Fair Value	$ 1,759	$ 4,683

Fair Value Measurements - Estim

Fair Value Measurements - Estimated Fair Values of Company's Financial Instruments (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
FINANCIAL ASSETS
Securities held for investment, Carrying Amount	$ 1,997	$ 1,428
Loans, net of allowance for loan losses, Carrying Amount	5,039,295	4,924,587
Securities held for investment, Fair Value	2,003	1,433
Loans held for sale, Fair Value	10,899	8,174
FINANCIAL LIABILITIES
Deposits, Carrying Amount	6,613,613	6,605,495
Short-term borrowings, Carrying Amount	1,000	1,675
Junior subordinated debentures, Carrying Amount	26,804	26,804
OFF-BALANCE SHEET FINANCIAL INSTRUMENTS
Loan commitments, Fair Value	2,277	2,158
Letters of credit, Fair Value	414	421
Level 2 Inputs [Member]
FINANCIAL ASSETS
Cash and cash equivalents, Carrying Amount	1,704,438	1,424,255
Securities held for investment, Carrying Amount	1,497	928
Loans held for sale, Carrying Amount	10,899	8,174
Cash and cash equivalents, Fair Value	1,704,438	1,424,255
Securities held for investment, Fair Value	1,503	933
Loans held for sale, Fair Value	10,899	8,174
FINANCIAL LIABILITIES
Deposits, Carrying Amount	6,613,613	6,605,495
Short-term borrowings, Carrying Amount	1,000	1,675
Junior subordinated debentures, Carrying Amount	26,804	26,804
Deposits, Fair Value	6,729,518	6,713,542
Short-term borrowings, Fair Value	1,000	1,675
Junior subordinated debentures, Fair Value	28,777	29,549
Level 3 Inputs [Member]
FINANCIAL ASSETS
Securities held for investment, Carrying Amount	500	500
Loans, net of allowance for loan losses, Carrying Amount	5,039,295	4,924,587
Securities held for investment, Fair Value	500	500
Loans, net of allowance for loan losses, Fair Value	$ 5,052,074	$ 4,901,159

Segment Information - Additiona

Segment Information - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2019Business_Unit
Segment Reporting [Abstract]
Number of principal business units	4

Segment Information - Results o

Segment Information - Results of Operations and Selected Financial Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Segment Reporting Information [Line Items]
Net interest income	$ 68,792	$ 64,880	$ 135,695	$ 127,915
Noninterest income	34,077	30,437	66,078	60,547
Income before taxes	43,828	39,836	84,842	76,777
Total Assets	7,642,021		7,642,021		$ 7,574,258
Operating Segments [Member] | Metropolitan Banks [Member]
Segment Reporting Information [Line Items]
Net interest income	21,438	21,084	42,791	41,388
Noninterest income	4,635	4,184	8,844	8,125
Income before taxes	14,866	14,883	30,235	29,619
Total Assets	2,795,525		2,795,525		2,743,876
Operating Segments [Member] | Community Banks [Member]
Segment Reporting Information [Line Items]
Net interest income	44,775	42,068	88,182	83,450
Noninterest income	16,243	14,832	31,128	28,785
Income before taxes	30,041	27,942	58,086	54,290
Total Assets	4,981,139		4,981,139		4,892,946
Operating Segments [Member] | Other Financial Services [Member]
Segment Reporting Information [Line Items]
Net interest income	1,411	1,358	2,582	2,833
Noninterest income	10,105	8,896	19,978	18,520
Income before taxes	5,572	4,028	10,071	9,071
Total Assets	45,972		45,972		84,706
Operating Segments [Member] | Executive, Operations & Support [Member]
Segment Reporting Information [Line Items]
Net interest income	1,168	370	2,140	244
Noninterest income	37,917	33,609	73,438	65,803
Income before taxes	27,590	23,622	52,613	43,537
Total Assets	883,471		883,471		861,782
Eliminations [Member]
Segment Reporting Information [Line Items]
Noninterest income	(34,823)	(31,084)	(67,310)	(60,686)
Income before taxes	(34,241)	$ (30,639)	(66,163)	$ (59,740)
Total Assets	$ (1,064,086)		$ (1,064,086)		$ (1,009,052)