BancFirst (BANF) 10-Q 3 May 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	Apr. 30, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Trading Symbol	BANF
Entity Registrant Name	BANCFIRST CORP /OK/
Entity Central Index Key	0000760498
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		32,626,588

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
ASSETS
Cash and due from banks	$ 185,958	$ 228,431
Interest-bearing deposits with banks	1,291,447	1,195,824
Securities held for investment (fair value: $1,223 and $1,433, respectively)	1,217	1,428
Securities available for sale at fair value	723,655	770,704
Loans held for sale	7,719	8,174
Loans (net of unearned interest)	5,042,502	4,975,976
Allowance for loan losses	(52,915)	(51,389)
Loans, net of allowance for loan losses	4,989,587	4,924,587
Premises and equipment, net	177,950	174,362
Other real estate owned	6,172	6,690
Intangible assets, net	15,701	16,470
Goodwill	79,749	79,749
Accrued interest receivable and other assets	229,845	167,839
Total assets	7,709,000	7,574,258
Deposits:
Noninterest-bearing	2,659,584	2,613,876
Interest-bearing	4,046,802	3,991,619
Total deposits	6,706,386	6,605,495
Short-term borrowings	5,200	1,675
Accrued interest payable and other liabilities	42,683	37,495
Junior subordinated debentures	26,804	26,804
Total liabilities	6,781,073	6,671,469
Stockholders' equity:
Common stock, $1.00 par, 40,000,000 shares authorized; shares issued and outstanding: 32,617,788 and 32,603,926, respectively	32,618	32,604
Capital surplus	150,195	149,709
Retained earnings	744,713	722,615
Accumulated other comprehensive loss, net of income tax of $137 and $(731), respectively	401	(2,139)
Total stockholders' equity	927,927	902,789
Total liabilities and stockholders' equity	7,709,000	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	Mar. 31, 2019	Dec. 31, 2018
Securities, fair value	$ 1,223	$ 1,433
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	40,000,000	40,000,000
Common stock, shares issued	32,617,788	32,603,926
Common stock, shares outstanding	32,617,788	32,603,926
Accumulated other comprehensive loss, tax expense (benefit)	$ 137	$ (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
	Mar. 31, 2019	Mar. 31, 2018
INTEREST INCOME
Loans, including fees	$ 68,730	$ 62,919
Securities:
Taxable	4,335	1,898
Tax-exempt	126	171
Federal funds sold	2	104
Interest-bearing deposits with banks	7,748	5,782
Total interest income	80,941	70,874
INTEREST EXPENSE
Deposits	13,537	7,269
Short-term borrowings	10	35
Junior subordinated debentures	491	535
Total interest expense	14,038	7,839
Net interest income	66,903	63,035
Provision for loan losses	1,684	314
Net interest income after provision for loan losses	65,219	62,721
NONINTEREST INCOME
Securities transactions (includes no accumulated other comprehensive income reclassifications)		(14)
Income from sales of loans	698	651
Insurance commissions	5,265	5,199
Cash management	3,776	3,021
(Loss)/gain on sale of other assets	(4)	26
Other	1,426	1,445
Total noninterest income	32,001	30,110
NONINTEREST EXPENSE
Salaries and employee benefits	36,171	34,190
Occupancy, net	2,627	3,402
Depreciation	2,985	2,410
Amortization of intangible assets	759	733
Data processing services	1,480	1,203
Net (income)/expense from other real estate owned	(484)	26
Marketing and business promotion	2,261	2,352
Deposit insurance	533	619
Other	9,874	10,955
Total noninterest expense	56,206	55,890
Income before taxes	41,014	36,941
Income tax expense	9,177	7,321
Net income	$ 31,837	$ 29,620
NET INCOME PER COMMON SHARE
Basic	$ 0.98	$ 0.91
Diluted	$ 0.96	$ 0.89
OTHER COMPREHENSIVE GAIN/(LOSS)
Unrealized gains/(losses) on securities, net of tax of $(868) and $474, respectively	$ 2,540	$ (1,388)
Other comprehensive gains/(losses), net of tax of $(868) and $474, respectively	2,540	(1,388)
Comprehensive income	34,377	28,232
Trust Revenue [Member]
NONINTEREST INCOME
Revenue	3,177	3,129
Service Charges on Deposits [Member]
NONINTEREST INCOME
Revenue	$ 17,663	$ 16,653

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Unaudited) (Parenthetical) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Securities transactions accumulated other comprehensive income reclassifications	$ 0	$ 0
Unrealized gains (losses) on securities, tax	(868,000)	474,000
Other comprehensive gains (losses), tax	$ (868,000)	$ 474,000

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		80	1,210
Shares issued for acquisitions		733	38,765
Stock-based compensation arrangements			306
Net income	$ 29,620			29,620
Dividends on common stock				(6,859)
Net change	(1,388)				(1,388)
Balance at end of period at Mar. 31, 2018	838,096	32,708	147,762	661,341	(3,715)
Balance at beginning of period at Dec. 31, 2018	902,789	32,604	149,709	722,615	(2,139)
Shares issued for stock options		14	312
Stock-based compensation arrangements			174
Net income	31,837			31,837
Dividends on common stock				(9,739)
Net change	2,540				2,540
Balance at end of period at Mar. 31, 2019	$ 927,927	$ 32,618	$ 150,195	$ 744,713	$ 401

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity (Unaudited) (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
RETAINED EARNINGS [Member]
Dividend on common stock	$ 0.30	$ 0.21

Consolidated Statements of Cash

Consolidated Statements of Cash Flow (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 31,837	$ 29,620
Adjustments to reconcile to net cash provided by operating activities:
Provision for loan losses	1,684	314
Depreciation and amortization	3,744	3,143
Net amortization of securities premiums and discounts	(1,948)	(49)
Realized securities losses		14
Gain on sales of loans	(698)	(651)
Cash receipts from the sale of loans originated for sale	43,229	44,558
Cash disbursements for loans originated for sale	(42,094)	(43,949)
Deferred income tax benefit	(459)	(117)
Gain on other assets	(499)	(21)
Increase in interest receivable	(1,500)	(1,111)
Increase in interest payable	382	353
Amortization of stock-based compensation arrangements	174	306
Excess tax benefit from stock-based compensation arrangements	(102)	(647)
Other, net	2,910	(5,408)
Net cash provided by operating activities	36,660	26,355
INVESTING ACTIVITIES
Net cash received from acquisitions, net of cash paid		6,248
Net decrease in federal funds sold		2,451
Purchases of available for sale securities		(30,861)
Proceeds from maturities, calls and paydowns of held for investment securities	210	213
Proceeds from maturities, calls and paydowns of available for sale securities	2,406	5,729
Proceeds from sales of available for sale securities		1,460
Purchase of equity securities	(1,828)
Proceeds from paydowns and sales of equity securities	110
Net change in loans	(67,249)	48,819
Purchases of premises, equipment and computer software	(6,792)	(7,168)
Other, net	(5,019)	(857)
Net cash (used in) provided by investing activities	(78,162)	26,034
FINANCING ACTIVITIES
Net change in deposits	100,582	(31,953)
Net increase/(decrease) in short-term borrowings	3,525	(800)
Issuance of common stock in connection with stock options, net	326	1,290
Cash dividends paid	(9,781)	(6,698)
Net cash provided by (used in) financing activities	94,652	(38,161)
Net increase in cash, due from banks and interest-bearing deposits	53,150	14,228
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	1,477,405	1,772,103
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid during the period for interest	13,655	7,486
Cash paid during the period for income taxes		1,250
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	$ 9,784	$ 6,854

Description of Business and Sum

Description of Business and Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 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 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 early in 2019. The Company has performed test runs of the new processes and controls and expects to begin full parallel runs by mid-2019. The impact of the standard will depend on the composition of the Company’s portfolio as well as economic conditions and forecasts at the time of adoption. The adoption of ASU 2016-13 could result in an increase 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 we establish an allowance for expected credit losses for certain debt securities and other financial assets. While we are 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	3 Months Ended
	Mar. 31, 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, the Company entered into an agreement to acquire Pegasus Bank. See Note (12) for additional information on this subsequent event. 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	3 Months Ended
	Mar. 31, 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 March 31, 2019 (Dollars in thousands) Mortgage backed securities (1) $ 122 $ 6 $ — $ 128 States and political subdivisions 595 — — 595 Other securities 500 — — 500 Total $ 1,217 $ 6 $ — $ 1,223 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 March 31, 2019 (Dollars in thousands) U.S. treasuries $ 651,860 $ 2,847 $ (1,957 ) $ 652,750 U.S. federal agencies 28,106 — (152 ) 27,954 Mortgage backed securities (1) 16,162 126 (576 ) 15,712 States and political subdivisions 26,989 317 (67 ) 27,239 Total $ 723,117 $ 3,290 $ (2,752 ) $ 723,655 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. March 31, 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 $ 295 $ 295 $ 495 $ 495 After one year but within five years 368 370 369 370 After five years but within ten years 552 556 562 565 After ten years 2 2 2 3 Total $ 1,217 $ 1,223 $ 1,428 $ 1,433 Available for Sale Contractual maturity of debt securities: Within one year $ 403,084 $ 402,210 $ 411,256 $ 410,327 After one year but within five years 273,033 274,838 313,416 311,924 After five years but within ten years 7,265 7,487 7,524 7,685 After ten years 39,735 39,120 41,378 40,768 Total debt securities $ 723,117 $ 723,655 $ 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: March 31, 2019 December 31, 2018 (Dollars Book value of pledged securities $ 418,807 $ 472,053 Non-Cash investing activities On March 31, 2019, the Company had a $50.0 million security that matured, was removed from the securities portfolio and moved into accrued interest receivable and other assets on the balance sheet. The cash for this matured security was received the following day on April 1, 2019.

Loans and Allowance for Loan Lo

Loans and Allowance for Loan Losses	3 Months Ended
	Mar. 31, 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: March 31, 2019 December 31, 2018 Amount Percent Amount Percent (Dollars in thousands) Commercial and financial: Commercial and industrial $ 1,043,848 20.70 % $ 1,032,787 20.76 % Oil & gas production and equipment 106,991 2.12 94,729 1.90 Agriculture 130,717 2.59 136,313 2.74 State and political subdivisions: Taxable 73,051 1.45 76,211 1.53 Tax-exempt 49,833 0.99 48,415 0.97 Real estate: Construction 469,826 9.32 451,224 9.07 Farmland 227,526 4.51 219,241 4.41 One to four family residences 982,605 19.49 979,170 19.68 Multifamily residential properties 68,412 1.36 65,949 1.33 Commercial 1,514,266 30.03 1,506,937 30.28 Consumer 326,002 6.46 328,069 6.59 Other (not classified above) 49,425 0.98 36,931 0.74 Total loans $ 5,042,502 100.00 % $ 4,975,976 100.00 % The Company’s loans are mostly to customers within Oklahoma and approximately 65% 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 $61 million at March 31, 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: March 31, December 31, 2019 2018 (Dollars in thousands) Past due 90 days or more and still accruing $ 2,170 $ 1,916 Nonaccrual 21,594 22,603 Restructured 14,552 13,188 Total nonperforming and restructured loans 38,316 37,707 Other real estate owned and repossessed assets 6,433 6,873 Total nonperforming and restructured assets $ 44,749 $ 44,580 Had nonaccrual loans performed in accordance with their original contractual terms, the Company would have recognized additional interest income of approximately $544,000 for the three months ended March 31, 2019 and approximately $542,000 for the three months ended March 31, 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. March 31, 2019 December 31, 2018 (Dollars in thousands) Real estate: Non-residential real estate owner occupied $ 769 $ 838 Non-residential real estate other 1,030 187 Residential real estate permanent mortgage 1,208 954 Residential real estate all other 5,729 5,488 Commercial and financial: Non-consumer non-real estate 5,132 5,682 Consumer non-real estate 422 437 Other loans 393 490 Acquired loans 6,911 8,527 Total $ 21,594 $ 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 March 31, 2019 Real estate: Non-residential real estate owner occupied $ 8,948 $ 30 $ 123 $ 9,101 $ 629,918 $ 639,019 $ 117 Non-residential real estate other 2,089 152 593 2,834 1,186,935 1,189,769 121 Residential real estate permanent mortgage 3,374 634 801 4,809 328,857 333,666 401 Residential real estate all other 2,239 4,002 2,327 8,568 832,865 841,433 247 Commercial and financial: Non-consumer non-real estate 3,226 999 2,164 6,389 1,320,215 1,326,604 453 Consumer non-real estate 1,498 548 311 2,357 324,649 327,006 173 Other loans 1,485 156 92 1,733 140,687 142,420 — Acquired loans 1,528 1,689 4,290 7,507 235,078 242,585 658 Total $ 24,387 $ 8,210 $ 10,701 $ 43,298 $ 4,999,204 $ 5,042,502 $ 2,170 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 March 31, 2019 and March 31, 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 March 31, 2019 Real estate: Non-residential real estate owner occupied $ 7,730 $ 7,619 $ 228 $ 7,362 Non-residential real estate other 1,976 1,722 212 1,247 Residential real estate permanent mortgage 1,871 1,619 143 1,618 Residential real estate all other 7,153 6,854 2,478 7,024 Commercial and financial: Non-consumer non-real estate 18,769 11,120 857 10,976 Consumer non-real estate 767 660 133 724 Other loans 694 422 31 369 Acquired loans 12,764 10,228 2 11,078 Total $ 51,724 $ 40,244 $ 4,084 $ 40,398 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 March 31, 2019 Real estate: Non-residential real estate owner occupied $ 459,381 $ 153,357 $ 25,456 $ 825 $ — $ 639,019 Non-residential real estate other 956,483 206,591 25,665 1,030 — 1,189,769 Residential real estate permanent mortgage 283,951 41,010 7,080 1,625 — 333,666 Residential real estate all other 659,846 159,703 15,943 5,941 — 841,433 Commercial and financial: Non-consumer non-real estate 1,033,690 264,192 24,726 3,996 — 1,326,604 Consumer non-real estate 302,263 21,860 2,246 637 — 327,006 Other loans 136,737 4,317 1,348 18 — 142,420 Acquired loans 127,474 94,135 13,455 7,206 315 242,585 Total $ 3,959,825 $ 945,165 $ 115,919 $ 21,278 $ 315 $ 5,042,502 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 March 31, 2019 Real estate: Non-residential real estate owner occupied $ 6,328 $ (6 ) $ 1 $ (5 ) $ 332 $ 6,655 Non-residential real estate other 11,027 (6 ) — (6 ) 341 11,362 Residential real estate permanent mortgage 3,261 (63 ) 5 (58 ) 58 3,261 Residential real estate all other 10,673 (52 ) 2 (50 ) 423 11,046 Commercial and financial: Non-consumer non-real estate 13,151 (70 ) 67 (3 ) 1,261 14,409 Consumer non-real estate 3,065 (120 ) 71 (49 ) 56 3,072 Other loans 2,423 — 35 35 (50 ) 2,408 Acquired loans 1,461 (26 ) 4 (22 ) (737 ) 702 Total $ 51,389 $ (343 ) $ 185 $ (158 ) $ 1,684 $ 52,915 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 March 31, 2018 Real estate: Non-residential real estate owner occupied $ 6,195 $ (19 ) $ 1 $ (18 ) $ 473 $ 6,650 Non-residential real estate other 10,519 (1 ) 39 38 (9 ) 10,548 Residential real estate permanent mortgage 3,226 (56 ) 3 (53 ) 108 3,281 Residential real estate all other 9,672 (90 ) 3 (87 ) 246 9,831 Commercial and financial: Non-consumer non-real estate 15,334 (156 ) 13 (143 ) (406 ) 14,785 Consumer non-real estate 2,793 (250 ) 80 (170 ) 76 2,699 Other loans 2,481 — 12 12 (157 ) 2,336 Acquired loans 1,446 (27 ) 18 (9 ) (17 ) 1,420 Total $ 51,666 $ (599 ) $ 169 $ (430 ) $ 314 $ 51,550 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 March 31, 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. $ 986 $ 5,669 $ 669 $ 5,659 Non-residential real estate other 1,024 10,338 1,119 9,908 Residential real estate permanent mortgage 457 2,804 505 2,756 Residential real estate all other 3,691 7,355 3,413 7,260 Commercial and financial: Non-consumer non-real estate 3,069 11,340 2,114 11,037 Consumer non-real estate 375 2,697 374 2,691 Other loans 26 2,382 65 2,358 Acquired loans — 702 — 1,461 Total $ 9,628 $ 43,287 $ 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 March 31, 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 $ 26,281 $ 612,738 $ — $ 17,846 $ 608,775 $ — Non-residential real estate other 26,695 1,163,074 — 25,333 1,120,795 — Residential real estate permanent mortgage 8,705 324,961 — 9,026 319,676 — Residential real estate all other 21,883 819,550 — 21,285 806,219 — Commercial and financial: Non-consumer non-real estate 28,722 1,297,882 — 19,432 1,264,222 — Consumer non-real estate 2,875 324,131 — 3,093 323,769 — Other loans 26 142,394 — 209 141,700 — Acquired loans 14,057 221,608 6,920 22,132 265,084 7,380 Total $ 129,244 $ 4,906,338 $ 6,920 $ 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. Transfers from loans and premises and equipment to other real estate owned and repossessed assets during the periods presented, are summarized as follows: Three Months Ended March 31, 2019 2018 (Dollars in thousands) Other real estate owned $ 591 $ 402 Repossessed assets 301 220 Total $ 892 $ 622

Intangible Assets

Intangible Assets	3 Months Ended
	Mar. 31, 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 March 31, 2019 Core deposit intangibles $ 25,907 $ (11,785 ) $ 14,122 Customer relationship intangibles 5,699 (4,202 ) 1,497 Mortgage servicing intangibles 392 (310 ) 82 Total $ 31,998 $ (16,297 ) $ 15,701 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) Three months ended March 31, 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	3 Months Ended
	Mar. 31, 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 buildings. Rent expense for all operating leases totaled approximately $357,000 and $381,000 for the three months ended March 31, 2019 and March 31, 2018, respectively. As of March 31, 2019, right of use lease asset, which is included in accrued interest receivable and other assets on the balance sheet totaled $4.3 million, and the related lease liability, which is included in accrued interest payable and other liabilities on the balance sheet totaled $4.3 million. There have been no significant changes in our expected future minimum lease payments since December 31, 2018. The future minimum lease payments are disclosed in Note (19) to the Company’s Annual Report on Form 10-K for the year ended December 31, 2018. As of March 31, 2019, our operating leases have a weighted-average remaining lease term of 4.4 years and a weighted-average discount rate of 3.6 percent. Maturity of Operating Lease Liabilities March 31, 2019 (Dollars in thousands) 2019 (nine months) $ 97 2020 1,024 2021 150 2022 1,288 2023 955 Thereafter 737 Operating Lease Liability $ 4,251 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 during the first quarter of 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 in place leases beyond 2023. The following table presents the scheduled minimum future contractual rent to be received under the remaining non-cancelable term of the operating leases: March 31, 2019 (Dollars in thousands) 2019 (nine months) $ 3,126 2020 2,524 2021 1,624 2022 973 2023 509 Total Future Minimum Lease Payments $ 8,756

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 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 6,400,000 shares. At March 31, 2019, there were 265,470 shares available for future grants. The BancFirst ISOP will terminate on December 31, 2019, 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 March 31, 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 520,000 shares. At March 31, 2019, there were 40,000 shares available for future grants. The BancFirst Directors’ Stock Option Plan will terminate on December 31, 2019, 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 March 31, 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) Three Months Ended March 31, 2019 Outstanding at December 31, 2018 1,216,700 $ 28.48 Options granted 40,000 55.38 Options exercised (5,500 ) 28.35 Options canceled, forfeited, or expired (22,500 ) 51.83 Outstanding at March 31, 2019 1,228,700 28.93 9.39 Yrs $ 28,536 Exercisable at March 31, 2019 613,700 21.78 6.98 Yrs $ 18,639 The following table has additional information regarding options exercised under both the BancFirst ISOP and the BancFirst Directors’ Stock Option Plan: Three Months Ended March 31, 2019 2018 (Dollars in thousands) Total intrinsic value of options exercised $ 145 $ 2,860 Cash received from options exercised 156 1,233 Tax benefit realized from options exercised 37 729 The fair value of each option grant is estimated on the date of grant using the Black-Scholes option-pricing model and is based on certain assumptions including risk-free rate of return, dividend yield, stock price volatility and the expected term. The fair value of each option is expensed over its vesting period. The following table is a summary of the Company’s recorded stock-based compensation expense: Three Months Ended March 31, 2019 2018 (Dollars in thousands) Stock-based compensation expense $ 174 $ 306 Tax benefit 44 78 Stock-based compensation expense, net of tax $ 130 $ 228 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: March 31, 2019 (Dollars in thousands) Unearned stock-based compensation expense $ 3,437 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: Three Months Ended March 31, 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 23.18% 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 222,220 shares. The BancFirst Deferred Stock Compensation Plan will terminate on December 31, 2019, 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 2,842 shares of common stock distributed from the BancFirst Deferred Stock Compensation Plan during the three months ended March 31, 2019 and March 31, 2018, respectively. A summary of the accumulated stock units is as follows: March 31, December 31, 2019 2018 Accumulated stock units 137,543 143,347 Average price $ 25.70 $ 24.91

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 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: Three Months Ended March 31, 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 March 31, 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 March 31, 2019: Total Capital (to Risk Weighted Assets)- BancFirst Corporation $ 911,073 16.32% $ 446,687 8.00% $ 586,277 10.50% N/A N/A BancFirst 788,443 14.14% 445,937 8.00% 585,292 10.50% $ 557,421 10.00% Common Equity Tier 1 Capital (to Risk Weighted Assets)- BancFirst Corporation $ 832,158 14.90% $ 251,262 4.50% $ 390,852 7.00% N/A N/A BancFirst 715,528 12.84% 250,839 4.50% 390,194 7.00% $ 362,323 6.50% Tier 1 Capital (to Risk Weighted Assets)- BancFirst Corporation $ 858,158 15.37% $ 335,016 6.00% $ 474,605 8.50% N/A N/A BancFirst 735,528 13.20% 334,452 6.00% 473,808 8.50% $ 445,937 8.00% Tier 1 Capital (to Total Assets)- BancFirst Corporation $ 858,158 11.38% $ 301,620 4.00% N/A N/A N/A N/A BancFirst 735,528 9.77% 301,212 4.00% N/A N/A $ 376,514 5.00% As of March 31, 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. The implementation of the capital conservation buffer began on January 1, 2016 at the 0.625% level and was phased in over a four-year period (increasing by that amount on each subsequent January 1, until it reached 2.5% on January 1, 2019). As of March 31, 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	3 Months Ended
	Mar. 31, 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 March 31, 2019 Basic Income available to common stockholders $ 31,837 32,612,399 $ 0.98 Dilutive effect of stock options — 680,453 Diluted Income available to common stockholders plus assumed exercises of stock options $ 31,837 33,292,852 $ 0.96 Three Months Ended March 31, 2018 Basic Income available to common stockholders $ 29,620 32,574,251 $ 0.91 Dilutive effect of stock options — 743,493 Diluted Income available to common stockholders plus assumed exercises of stock options $ 29,620 33,317,744 $ 0.89 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 March 31, 2019 180,000 Three Months Ended March 31, 2018 113,278

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 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) March 31, 2019 Securities available for sale: U.S. Treasury $ 652,750 $ — $ — $ 652,750 U.S. federal agencies — 27,954 — 27,954 Mortgage-backed securities — 2,311 13,401 15,712 States and political subdivisions — 27,239 — 27,239 Derivative assets — 51 — 51 Derivative liabilities — 49 — 49 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: Three Months Ended March 31, Twelve Months Ended December 31, 2019 2018 (Dollars in thousands) Balance at the beginning of the year $ 13,443 $ 14,467 Settlements (39 ) (1,037 ) Total unrealized (losses) gains (3 ) 13 Balance at the end of the period $ 13,401 $ 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 March 31, 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 March 31, 2019 Equity securities $ 9,239 Impaired loans (less specific allowance) 36,160 Repossessed assets 184 Other real estate owned 560 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: March 31, December 31, 2019 2018 Carrying Amount Fair Value Carrying Amount Fair Value (Dollars in thousands) FINANCIAL ASSETS Level 2 inputs: Cash and cash equivalents $ 1,477,405 $ 1,477,405 $ 1,424,255 $ 1,424,255 Securities held for investment 717 723 928 933 Loans held for sale 7,719 7,719 8,174 8,174 Level 3 inputs: Securities held for investment 500 500 500 500 Loans, net of allowance for loan losses 4,989,587 4,988,322 4,924,587 4,901,159 FINANCIAL LIABILITIES Level 2 inputs: Deposits 6,706,386 6,816,792 6,605,495 6,713,542 Short-term borrowings 5,200 5,200 1,675 1,675 Junior subordinated debentures 26,804 29,131 26,804 29,549 OFF-BALANCE SHEET FINANCIAL INSTRUMENTS Loan commitments 2,219 2,158 Letters of credit 410 421 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 March 31, 2019 or December 31, 2018.

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 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 March 31, 2019 Net interest income $ 21,353 $ 43,407 $ 1,171 $ 972 $ — $ 66,903 Noninterest income 4,209 14,885 9,873 35,521 (32,487 ) 32,001 Income before taxes 15,369 28,045 4,499 25,023 (31,922 ) 41,014 Three Months Ended March 31, 2018 Net interest income (expense) $ 20,304 $ 41,382 $ 1,475 $ (126 ) $ — $ 63,035 Noninterest income 3,941 13,953 9,624 32,194 (29,602 ) 30,110 Income before taxes 14,736 26,348 5,043 19,915 (29,101 ) 36,941 Total Assets: March 31, 2019 $ 2,763,523 $ 4,995,379 $ 69,430 $ 912,166 $ (1,031,498 ) $ 7,709,000 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.

Subsequent Event

Subsequent Event	3 Months Ended
	Mar. 31, 2019
Subsequent Events [Abstract]
Subsequent Event	(12) SUBSEQUENT EVENT On April 23, 2019 BancFirst Corporation entered into an agreement to acquire Pegasus Bank (“Pegasus”), for an aggregate cash purchase price of $122.0 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 and is subject to regulatory approval. 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.

Description of Business and S_2

Description of Business and Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 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 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 early in 2019. The Company has performed test runs of the new processes and controls and expects to begin full parallel runs by mid-2019. The impact of the standard will depend on the composition of the Company’s portfolio as well as economic conditions and forecasts at the time of adoption. The adoption of ASU 2016-13 could result in an increase 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 we establish an allowance for expected credit losses for certain debt securities and other financial assets. While we are 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)	3 Months Ended
	Mar. 31, 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 March 31, 2019 (Dollars in thousands) Mortgage backed securities (1) $ 122 $ 6 $ — $ 128 States and political subdivisions 595 — — 595 Other securities 500 — — 500 Total $ 1,217 $ 6 $ — $ 1,223 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 March 31, 2019 (Dollars in thousands) U.S. treasuries $ 651,860 $ 2,847 $ (1,957 ) $ 652,750 U.S. federal agencies 28,106 — (152 ) 27,954 Mortgage backed securities (1) 16,162 126 (576 ) 15,712 States and political subdivisions 26,989 317 (67 ) 27,239 Total $ 723,117 $ 3,290 $ (2,752 ) $ 723,655 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. March 31, 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 $ 295 $ 295 $ 495 $ 495 After one year but within five years 368 370 369 370 After five years but within ten years 552 556 562 565 After ten years 2 2 2 3 Total $ 1,217 $ 1,223 $ 1,428 $ 1,433 Available for Sale Contractual maturity of debt securities: Within one year $ 403,084 $ 402,210 $ 411,256 $ 410,327 After one year but within five years 273,033 274,838 313,416 311,924 After five years but within ten years 7,265 7,487 7,524 7,685 After ten years 39,735 39,120 41,378 40,768 Total debt securities $ 723,117 $ 723,655 $ 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: March 31, 2019 December 31, 2018 (Dollars Book value of pledged securities $ 418,807 $ 472,053

Loans and Allowance for Loan _2

Loans and Allowance for Loan Losses (Tables)	3 Months Ended
	Mar. 31, 2019
Receivables [Abstract]
Schedule of Loans Outstanding by Category	The following is a schedule of loans outstanding by category: March 31, 2019 December 31, 2018 Amount Percent Amount Percent (Dollars in thousands) Commercial and financial: Commercial and industrial $ 1,043,848 20.70 % $ 1,032,787 20.76 % Oil & gas production and equipment 106,991 2.12 94,729 1.90 Agriculture 130,717 2.59 136,313 2.74 State and political subdivisions: Taxable 73,051 1.45 76,211 1.53 Tax-exempt 49,833 0.99 48,415 0.97 Real estate: Construction 469,826 9.32 451,224 9.07 Farmland 227,526 4.51 219,241 4.41 One to four family residences 982,605 19.49 979,170 19.68 Multifamily residential properties 68,412 1.36 65,949 1.33 Commercial 1,514,266 30.03 1,506,937 30.28 Consumer 326,002 6.46 328,069 6.59 Other (not classified above) 49,425 0.98 36,931 0.74 Total loans $ 5,042,502 100.00 % $ 4,975,976 100.00 %
Summary of Nonperforming and Restructured Assets	The following is a summary of nonperforming and restructured assets: March 31, December 31, 2019 2018 (Dollars in thousands) Past due 90 days or more and still accruing $ 2,170 $ 1,916 Nonaccrual 21,594 22,603 Restructured 14,552 13,188 Total nonperforming and restructured loans 38,316 37,707 Other real estate owned and repossessed assets 6,433 6,873 Total nonperforming and restructured assets $ 44,749 $ 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. March 31, 2019 December 31, 2018 (Dollars in thousands) Real estate: Non-residential real estate owner occupied $ 769 $ 838 Non-residential real estate other 1,030 187 Residential real estate permanent mortgage 1,208 954 Residential real estate all other 5,729 5,488 Commercial and financial: Non-consumer non-real estate 5,132 5,682 Consumer non-real estate 422 437 Other loans 393 490 Acquired loans 6,911 8,527 Total $ 21,594 $ 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 March 31, 2019 Real estate: Non-residential real estate owner occupied $ 8,948 $ 30 $ 123 $ 9,101 $ 629,918 $ 639,019 $ 117 Non-residential real estate other 2,089 152 593 2,834 1,186,935 1,189,769 121 Residential real estate permanent mortgage 3,374 634 801 4,809 328,857 333,666 401 Residential real estate all other 2,239 4,002 2,327 8,568 832,865 841,433 247 Commercial and financial: Non-consumer non-real estate 3,226 999 2,164 6,389 1,320,215 1,326,604 453 Consumer non-real estate 1,498 548 311 2,357 324,649 327,006 173 Other loans 1,485 156 92 1,733 140,687 142,420 — Acquired loans 1,528 1,689 4,290 7,507 235,078 242,585 658 Total $ 24,387 $ 8,210 $ 10,701 $ 43,298 $ 4,999,204 $ 5,042,502 $ 2,170 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 March 31, 2019 and March 31, 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 March 31, 2019 Real estate: Non-residential real estate owner occupied $ 7,730 $ 7,619 $ 228 $ 7,362 Non-residential real estate other 1,976 1,722 212 1,247 Residential real estate permanent mortgage 1,871 1,619 143 1,618 Residential real estate all other 7,153 6,854 2,478 7,024 Commercial and financial: Non-consumer non-real estate 18,769 11,120 857 10,976 Consumer non-real estate 767 660 133 724 Other loans 694 422 31 369 Acquired loans 12,764 10,228 2 11,078 Total $ 51,724 $ 40,244 $ 4,084 $ 40,398 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 March 31, 2019 Real estate: Non-residential real estate owner occupied $ 459,381 $ 153,357 $ 25,456 $ 825 $ — $ 639,019 Non-residential real estate other 956,483 206,591 25,665 1,030 — 1,189,769 Residential real estate permanent mortgage 283,951 41,010 7,080 1,625 — 333,666 Residential real estate all other 659,846 159,703 15,943 5,941 — 841,433 Commercial and financial: Non-consumer non-real estate 1,033,690 264,192 24,726 3,996 — 1,326,604 Consumer non-real estate 302,263 21,860 2,246 637 — 327,006 Other loans 136,737 4,317 1,348 18 — 142,420 Acquired loans 127,474 94,135 13,455 7,206 315 242,585 Total $ 3,959,825 $ 945,165 $ 115,919 $ 21,278 $ 315 $ 5,042,502 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 March 31, 2019 Real estate: Non-residential real estate owner occupied $ 6,328 $ (6 ) $ 1 $ (5 ) $ 332 $ 6,655 Non-residential real estate other 11,027 (6 ) — (6 ) 341 11,362 Residential real estate permanent mortgage 3,261 (63 ) 5 (58 ) 58 3,261 Residential real estate all other 10,673 (52 ) 2 (50 ) 423 11,046 Commercial and financial: Non-consumer non-real estate 13,151 (70 ) 67 (3 ) 1,261 14,409 Consumer non-real estate 3,065 (120 ) 71 (49 ) 56 3,072 Other loans 2,423 — 35 35 (50 ) 2,408 Acquired loans 1,461 (26 ) 4 (22 ) (737 ) 702 Total $ 51,389 $ (343 ) $ 185 $ (158 ) $ 1,684 $ 52,915 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 March 31, 2018 Real estate: Non-residential real estate owner occupied $ 6,195 $ (19 ) $ 1 $ (18 ) $ 473 $ 6,650 Non-residential real estate other 10,519 (1 ) 39 38 (9 ) 10,548 Residential real estate permanent mortgage 3,226 (56 ) 3 (53 ) 108 3,281 Residential real estate all other 9,672 (90 ) 3 (87 ) 246 9,831 Commercial and financial: Non-consumer non-real estate 15,334 (156 ) 13 (143 ) (406 ) 14,785 Consumer non-real estate 2,793 (250 ) 80 (170 ) 76 2,699 Other loans 2,481 — 12 12 (157 ) 2,336 Acquired loans 1,446 (27 ) 18 (9 ) (17 ) 1,420 Total $ 51,666 $ (599 ) $ 169 $ (430 ) $ 314 $ 51,550
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 March 31, 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. $ 986 $ 5,669 $ 669 $ 5,659 Non-residential real estate other 1,024 10,338 1,119 9,908 Residential real estate permanent mortgage 457 2,804 505 2,756 Residential real estate all other 3,691 7,355 3,413 7,260 Commercial and financial: Non-consumer non-real estate 3,069 11,340 2,114 11,037 Consumer non-real estate 375 2,697 374 2,691 Other loans 26 2,382 65 2,358 Acquired loans — 702 — 1,461 Total $ 9,628 $ 43,287 $ 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 March 31, 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 $ 26,281 $ 612,738 $ — $ 17,846 $ 608,775 $ — Non-residential real estate other 26,695 1,163,074 — 25,333 1,120,795 — Residential real estate permanent mortgage 8,705 324,961 — 9,026 319,676 — Residential real estate all other 21,883 819,550 — 21,285 806,219 — Commercial and financial: Non-consumer non-real estate 28,722 1,297,882 — 19,432 1,264,222 — Consumer non-real estate 2,875 324,131 — 3,093 323,769 — Other loans 26 142,394 — 209 141,700 — Acquired loans 14,057 221,608 6,920 22,132 265,084 7,380 Total $ 129,244 $ 4,906,338 $ 6,920 $ 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 during the periods presented, are summarized as follows: Three Months Ended March 31, 2019 2018 (Dollars in thousands) Other real estate owned $ 591 $ 402 Repossessed assets 301 220 Total $ 892 $ 622

Intangible Assets (Tables)

Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 2019 Core deposit intangibles $ 25,907 $ (11,785 ) $ 14,122 Customer relationship intangibles 5,699 (4,202 ) 1,497 Mortgage servicing intangibles 392 (310 ) 82 Total $ 31,998 $ (16,297 ) $ 15,701 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) Three months ended March 31, 2019 Balance at beginning and end of period $ 13,767 $ 59,894 $ 5,464 $ 624 $ 79,749

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Schedule of Maturity of Operating Lease Liabilities	Maturity of Operating Lease Liabilities March 31, 2019 (Dollars in thousands) 2019 (nine months) $ 97 2020 1,024 2021 150 2022 1,288 2023 955 Thereafter 737 Operating Lease Liability $ 4,251
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: March 31, 2019 (Dollars in thousands) 2019 (nine months) $ 3,126 2020 2,524 2021 1,624 2022 973 2023 509 Total Future Minimum Lease Payments $ 8,756

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 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) Three Months Ended March 31, 2019 Outstanding at December 31, 2018 1,216,700 $ 28.48 Options granted 40,000 55.38 Options exercised (5,500 ) 28.35 Options canceled, forfeited, or expired (22,500 ) 51.83 Outstanding at March 31, 2019 1,228,700 28.93 9.39 Yrs $ 28,536 Exercisable at March 31, 2019 613,700 21.78 6.98 Yrs $ 18,639
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 March 31, 2019 2018 (Dollars in thousands) Total intrinsic value of options exercised $ 145 $ 2,860 Cash received from options exercised 156 1,233 Tax benefit realized from options exercised 37 729
Stock-based Employee Compensation Expense	The following table is a summary of the Company’s recorded stock-based compensation expense: Three Months Ended March 31, 2019 2018 (Dollars in thousands) Stock-based compensation expense $ 174 $ 306 Tax benefit 44 78 Stock-based compensation expense, net of tax $ 130 $ 228
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: March 31, 2019 (Dollars in thousands) Unearned stock-based compensation expense $ 3,437
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: Three Months Ended March 31, 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 23.18% Expected term 10 Yrs 10 Yrs
Summary of Accumulated Stock Units	A summary of the accumulated stock units is as follows: March 31, December 31, 2019 2018 Accumulated stock units 137,543 143,347 Average price $ 25.70 $ 24.91

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2019
Equity [Abstract]
Summary of Shares Repurchased Under Stock Purchase Program	The following table is a summary of the shares under the program: Three Months Ended March 31, 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 March 31, 2019: Total Capital (to Risk Weighted Assets)- BancFirst Corporation $ 911,073 16.32% $ 446,687 8.00% $ 586,277 10.50% N/A N/A BancFirst 788,443 14.14% 445,937 8.00% 585,292 10.50% $ 557,421 10.00% Common Equity Tier 1 Capital (to Risk Weighted Assets)- BancFirst Corporation $ 832,158 14.90% $ 251,262 4.50% $ 390,852 7.00% N/A N/A BancFirst 715,528 12.84% 250,839 4.50% 390,194 7.00% $ 362,323 6.50% Tier 1 Capital (to Risk Weighted Assets)- BancFirst Corporation $ 858,158 15.37% $ 335,016 6.00% $ 474,605 8.50% N/A N/A BancFirst 735,528 13.20% 334,452 6.00% 473,808 8.50% $ 445,937 8.00% Tier 1 Capital (to Total Assets)- BancFirst Corporation $ 858,158 11.38% $ 301,620 4.00% N/A N/A N/A N/A BancFirst 735,528 9.77% 301,212 4.00% N/A N/A $ 376,514 5.00%

Net Income Per Common Share (Ta

Net Income Per Common Share (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 2019 Basic Income available to common stockholders $ 31,837 32,612,399 $ 0.98 Dilutive effect of stock options — 680,453 Diluted Income available to common stockholders plus assumed exercises of stock options $ 31,837 33,292,852 $ 0.96 Three Months Ended March 31, 2018 Basic Income available to common stockholders $ 29,620 32,574,251 $ 0.91 Dilutive effect of stock options — 743,493 Diluted Income available to common stockholders plus assumed exercises of stock options $ 29,620 33,317,744 $ 0.89
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 March 31, 2019 180,000 Three Months Ended March 31, 2018 113,278

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 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) March 31, 2019 Securities available for sale: U.S. Treasury $ 652,750 $ — $ — $ 652,750 U.S. federal agencies — 27,954 — 27,954 Mortgage-backed securities — 2,311 13,401 15,712 States and political subdivisions — 27,239 — 27,239 Derivative assets — 51 — 51 Derivative liabilities — 49 — 49 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: Three Months Ended March 31, Twelve Months Ended December 31, 2019 2018 (Dollars in thousands) Balance at the beginning of the year $ 13,443 $ 14,467 Settlements (39 ) (1,037 ) Total unrealized (losses) gains (3 ) 13 Balance at the end of the period $ 13,401 $ 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 March 31, 2019 Equity securities $ 9,239 Impaired loans (less specific allowance) 36,160 Repossessed assets 184 Other real estate owned 560 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: March 31, December 31, 2019 2018 Carrying Amount Fair Value Carrying Amount Fair Value (Dollars in thousands) FINANCIAL ASSETS Level 2 inputs: Cash and cash equivalents $ 1,477,405 $ 1,477,405 $ 1,424,255 $ 1,424,255 Securities held for investment 717 723 928 933 Loans held for sale 7,719 7,719 8,174 8,174 Level 3 inputs: Securities held for investment 500 500 500 500 Loans, net of allowance for loan losses 4,989,587 4,988,322 4,924,587 4,901,159 FINANCIAL LIABILITIES Level 2 inputs: Deposits 6,706,386 6,816,792 6,605,495 6,713,542 Short-term borrowings 5,200 5,200 1,675 1,675 Junior subordinated debentures 26,804 29,131 26,804 29,549 OFF-BALANCE SHEET FINANCIAL INSTRUMENTS Loan commitments 2,219 2,158 Letters of credit 410 421

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 2019 Net interest income $ 21,353 $ 43,407 $ 1,171 $ 972 $ — $ 66,903 Noninterest income 4,209 14,885 9,873 35,521 (32,487 ) 32,001 Income before taxes 15,369 28,045 4,499 25,023 (31,922 ) 41,014 Three Months Ended March 31, 2018 Net interest income (expense) $ 20,304 $ 41,382 $ 1,475 $ (126 ) $ — $ 63,035 Noninterest income 3,941 13,953 9,624 32,194 (29,602 ) 30,110 Income before taxes 14,736 26,348 5,043 19,915 (29,101 ) 36,941 Total Assets: March 31, 2019 $ 2,763,523 $ 4,995,379 $ 69,430 $ 912,166 $ (1,031,498 ) $ 7,709,000 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) $ in Millions	Mar. 31, 2019USD ($)
Accounting Policies [Abstract]
Right-of-use lease assets	$ 4.3
Lease liabilities	$ 4.3

Recent Developments Including M

Recent Developments Including Mergers and Acquisitions - Additional Information (Detail) $ in Thousands	Dec. 14, 2018USD ($)ParkingSpaces	Aug. 31, 2018USD ($)ft²Floor	Jan. 11, 2018USD ($)CommunityLocation	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Business Combination Separately Recognized Transactions [Line Items]
Goodwill				$ 79,749	$ 79,749
Number of additional banking communities | Community			5
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
BFTower LLC [Member] | Cotter Ranch Tower [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
BFTower LLC [Member] | Cotter Ranch Tower [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

Securities - Summary of Amortiz

Securities - Summary of Amortized Cost and Estimated Fair Values of Debt Securities Held for Investment (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 1,217	$ 1,428
Gross Unrealized Gains	6	5
Estimated Fair Value	1,223	1,433
Mortgage Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	122	133
Gross Unrealized Gains	6	5
Estimated Fair Value	128	138
States and Political Subdivisions [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	595	795
Estimated Fair Value	595	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	Mar. 31, 2019	Dec. 31, 2018
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 723,117	$ 773,574
Gross Unrealized Gains	3,290	1,499
Gross Unrealized Losses	(2,752)	(4,369)
Estimated Fair Value	723,655	770,704
U.S. Treasuries [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	651,860	699,882
Gross Unrealized Gains	2,847	1,108
Gross Unrealized Losses	(1,957)	(3,524)
Estimated Fair Value	652,750	697,466
U.S. Federal Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	28,106	30,079
Gross Unrealized Losses	(152)	(160)
Estimated Fair Value	27,954	29,919
Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	16,162	16,367
Gross Unrealized Gains	126	114
Gross Unrealized Losses	(576)	(573)
Estimated Fair Value	15,712	15,908
States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	26,989	27,246
Gross Unrealized Gains	317	277
Gross Unrealized Losses	(67)	(112)
Estimated Fair Value	$ 27,239	$ 27,411

Securities - Maturity of Debt S

Securities - Maturity of Debt Securities (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Held for Investment, Contractual maturity of debt securities, Amortized Cost
Amortized cost, Within one year	$ 295	$ 495
Amortized cost, After one year but within five years	368	369
Amortized cost, After five years but within ten years	552	562
Amortized cost, After ten years	2	2
Amortized Cost	1,217	1,428
Available for sale, Contractual maturity of debt securities, Amortized Cost
Amortized Cost, Within one year	403,084	411,256
Amortized Cost, After one year but within five years	273,033	313,416
Amortized Cost, After five years but within ten years	7,265	7,524
Amortized Cost, After ten years	39,735	41,378
Amortized Cost	723,117	773,574
Held for Investment, Contractual maturity of debt securities, Estimated Fair Value
Estimated Fair Value, Within one year	295	495
Estimated Fair Value, After one year but within five years	370	370
Estimated Fair Value, After five years but within ten years	556	565
Estimated Fair Value, After ten years	2	3
Estimated Fair Value	1,223	1,433
Available for sale, Contractual maturity of debt securities, Estimated Fair Value
Estimated Fair Value, Within one year	402,210	410,327
Estimated Fair Value, After one year but within five years	274,838	311,924
Estimated Fair Value, After five years but within ten years	7,487	7,685
Estimated Fair Value, After ten years	39,120	40,768
Total debt securities	$ 723,655	$ 770,704

Securities - Company's Book Val

Securities - Company's Book Value of Pledged Debt Securities (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Pledged Financial Instruments Not Separately Reported Securities Pledged By Type Of Security [Abstract]
Book value of pledged securities	$ 418,807	$ 472,053

Securities - Additional Informa

Securities - Additional Information (Detail) $ in Millions	Mar. 31, 2019USD ($)
Accrued Interest Receivable and Other Assets [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities matured	$ 50

Loans and Allowance for Loan _3

Loans and Allowance for Loan Losses - Schedule of Loans Outstanding by Category (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 5,042,502	$ 4,975,976
Percent	100.00%	100.00%
Taxable [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 73,051	$ 76,211
Percent	1.45%	1.53%
Tax-exempt [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 49,833	$ 48,415
Percent	0.99%	0.97%
Commercial and Financial [Member] | Commercial and Industrial [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 1,043,848	$ 1,032,787
Percent	20.70%	20.76%
Commercial and Financial [Member] | Oil & Gas Production And Equipment [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 106,991	$ 94,729
Percent	2.12%	1.90%
Commercial and Financial [Member] | Agriculture [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 130,717	$ 136,313
Percent	2.59%	2.74%
Real Estate [Member] | Construction [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 469,826	$ 451,224
Percent	9.32%	9.07%
Real Estate [Member] | Farmland [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 227,526	$ 219,241
Percent	4.51%	4.41%
Real Estate [Member] | One to Four Family Residences [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 982,605	$ 979,170
Percent	19.49%	19.68%
Real Estate [Member] | Multifamily Residential Properties [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 68,412	$ 65,949
Percent	1.36%	1.33%
Real Estate [Member] | Commercial [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 1,514,266	$ 1,506,937
Percent	30.03%	30.28%
Consumer [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 326,002	$ 328,069
Percent	6.46%	6.59%
Other (Not Classified Above) [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 49,425	$ 36,931
Percent	0.98%	0.74%

Loans and Allowance for Loan _4

Loans and Allowance for Loan Losses - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 5,042,502,000		$ 4,975,976,000
Percentage of loans secured by real estate	65.00%
Interest income that would have been recognized	$ 544,000	$ 542,000
Interest income recognized on impaired loans	0	$ 0
Commercial and Industrial [Member] | Ancillary Services [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 61,000,000		$ 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	Mar. 31, 2019	Dec. 31, 2018
Summary Of Nonperforming And Restructured Assets [Abstract]
Past due 90 days or more and still accruing	$ 2,170	$ 1,916
Nonaccrual	21,594	22,603
Restructured	14,552	13,188
Total nonperforming and restructured loans	38,316	37,707
Other real estate owned and repossessed assets	6,433	6,873
Total nonperforming and restructured assets	$ 44,749	$ 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	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans, Total	$ 21,594	$ 22,603
Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans, Total	769	838
Real Estate [Member] | Non-residential Real Estate Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans, Total	1,030	187
Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans, Total	1,208	954
Real Estate [Member] | Residential Real Estate All Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans, Total	5,729	5,488
Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans, Total	5,132	5,682
Consumer Non-real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans, Total	422	437
Other Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans, Total	393	490
Acquired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans, Total	$ 6,911	$ 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	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	$ 43,298	$ 38,271
Current Loans	4,999,204	4,937,705
Total Loans	5,042,502	4,975,976
Accruing Loans 90 Days or More Past Due	2,170	1,916
Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	9,101	5,967
Current Loans	629,918	620,654
Total Loans	639,019	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	2,834	2,918
Current Loans	1,186,935	1,143,210
Total Loans	1,189,769	1,146,128
Accruing Loans 90 Days or More Past Due	121
Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	4,809	3,794
Current Loans	328,857	324,908
Total Loans	333,666	328,702
Accruing Loans 90 Days or More Past Due	401	430
Real Estate [Member] | Residential Real Estate All Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	8,568	4,819
Current Loans	832,865	822,685
Total Loans	841,433	827,504
Accruing Loans 90 Days or More Past Due	247	612
Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	6,389	5,155
Current Loans	1,320,215	1,278,499
Total Loans	1,326,604	1,283,654
Accruing Loans 90 Days or More Past Due	453	282
Consumer Non-real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	2,357	3,115
Current Loans	324,649	323,747
Total Loans	327,006	326,862
Accruing Loans 90 Days or More Past Due	173	325
Other Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	1,733	658
Current Loans	140,687	141,251
Total Loans	142,420	141,909
Acquired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	7,507	11,845
Current Loans	235,078	282,751
Total Loans	242,585	294,596
Accruing Loans 90 Days or More Past Due	658	267
30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	24,387	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	8,948	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	2,089	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	3,374	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	2,239	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	3,226	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	1,498	1,991
30 to 59 Days Past Due [Member] | Other Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	1,485	322
30 to 59 Days Past Due [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	1,528	5,240
60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	8,210	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	30	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	152	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	634	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	4,002	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	999	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	548	565
60 to 89 Days Past Due [Member] | Other Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	156	158
60 to 89 Days Past Due [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	1,689	1,669
90 Days and Greater [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	10,701	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	123	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	593	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	801	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	2,327	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	2,164	833
90 Days and Greater [Member] | Consumer Non-real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	311	559
90 Days and Greater [Member] | Other Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	92	178
90 Days and Greater [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	$ 4,290	$ 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	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	$ 51,724	$ 50,032
Recorded Investment with Allowance	40,244	38,257
Related Allowance	4,084	3,861
Average Recorded Investment	40,398	47,117
Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	7,730	7,126
Recorded Investment with Allowance	7,619	6,933
Related Allowance	228	202
Average Recorded Investment	7,362	7,739
Real Estate [Member] | Non-residential Real Estate Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	1,976	949
Recorded Investment with Allowance	1,722	757
Related Allowance	212	50
Average Recorded Investment	1,247	6,057
Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	1,871	1,789
Recorded Investment with Allowance	1,619	1,545
Related Allowance	143	127
Average Recorded Investment	1,618	1,650
Real Estate [Member] | Residential Real Estate All Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	7,153	7,177
Recorded Investment with Allowance	6,854	6,862
Related Allowance	2,478	2,433
Average Recorded Investment	7,024	7,154
Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	18,769	18,507
Recorded Investment with Allowance	11,120	10,977
Related Allowance	857	881
Average Recorded Investment	10,976	12,140
Consumer Non-real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	767	928
Recorded Investment with Allowance	660	829
Related Allowance	133	131
Average Recorded Investment	724	846
Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	694	710
Recorded Investment with Allowance	422	490
Related Allowance	31	35
Average Recorded Investment	369	481
Acquired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	12,764	12,846
Recorded Investment with Allowance	10,228	9,864
Related Allowance	2	2
Average Recorded Investment	$ 11,078	$ 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	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 5,042,502	$ 4,975,976
Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	639,019	626,621
Real Estate [Member] | Non-residential Real Estate Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	1,189,769	1,146,128
Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	333,666	328,702
Real Estate [Member] | Residential Real Estate All Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	841,433	827,504
Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	1,326,604	1,283,654
Consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	327,006	326,862
Other Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	142,420	141,909
Acquired Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	242,585	294,596
Grade 1 [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	3,959,825	3,902,046
Grade 1 [Member] | Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	459,381	451,059
Grade 1 [Member] | Real Estate [Member] | Non-residential Real Estate Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	956,483	932,454
Grade 1 [Member] | Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	283,951	279,870
Grade 1 [Member] | Real Estate [Member] | Residential Real Estate All Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	659,846	644,217
Grade 1 [Member] | Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	1,033,690	1,000,089
Grade 1 [Member] | Consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	302,263	302,217
Grade 1 [Member] | Other Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	136,737	136,132
Grade 1 [Member] | Acquired Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	127,474	156,008
Grade 2 [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	945,165	948,216
Grade 2 [Member] | Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	153,357	157,715
Grade 2 [Member] | Real Estate [Member] | Non-residential Real Estate Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	206,591	188,341
Grade 2 [Member] | Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	41,010	39,806
Grade 2 [Member] | Real Estate [Member] | Residential Real Estate All Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	159,703	162,003
Grade 2 [Member] | Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	264,192	264,134
Grade 2 [Member] | Consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	21,860	21,600
Grade 2 [Member] | Other Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	4,317	5,542
Grade 2 [Member] | Acquired Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	94,135	109,075
Grade 3 [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	115,919	103,111
Grade 3 [Member] | Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	25,456	16,949
Grade 3 [Member] | Real Estate [Member] | Non-residential Real Estate Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	25,665	25,146
Grade 3 [Member] | Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	7,080	7,401
Grade 3 [Member] | Real Estate [Member] | Residential Real Estate All Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	15,943	15,232
Grade 3 [Member] | Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	24,726	15,128
Grade 3 [Member] | Consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	2,246	2,255
Grade 3 [Member] | Other Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	1,348	116
Grade 3 [Member] | Acquired Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	13,455	20,884
Grade 4 [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	21,278	22,258
Grade 4 [Member] | Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	825	898
Grade 4 [Member] | Real Estate [Member] | Non-residential Real Estate Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	1,030	187
Grade 4 [Member] | Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	1,625	1,625
Grade 4 [Member] | Real Estate [Member] | Residential Real Estate All Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	5,941	6,052
Grade 4 [Member] | Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	3,996	4,303
Grade 4 [Member] | Consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	637	790
Grade 4 [Member] | Other Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	18	119
Grade 4 [Member] | Acquired Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	7,206	8,284
Grade 5 [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	315	345
Grade 5 [Member] | Acquired Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 315	$ 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
	Mar. 31, 2019	Mar. 31, 2018
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of period	$ 51,389	$ 51,666
Charge- offs	(343)	(599)
Recoveries	185	169
Net charge- offs	(158)	(430)
Provisions charged to operations	1,684	314
Balance at end of period	52,915	51,550
Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of period	6,328	6,195
Charge- offs	(6)	(19)
Recoveries	1	1
Net charge- offs	(5)	(18)
Provisions charged to operations	332	473
Balance at end of period	6,655	6,650
Real Estate [Member] | Non-residential Real Estate Other [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of period	11,027	10,519
Charge- offs	(6)	(1)
Recoveries		39
Net charge- offs	(6)	38
Provisions charged to operations	341	(9)
Balance at end of period	11,362	10,548
Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of period	3,261	3,226
Charge- offs	(63)	(56)
Recoveries	5	3
Net charge- offs	(58)	(53)
Provisions charged to operations	58	108
Balance at end of period	3,261	3,281
Real Estate [Member] | Residential Real Estate All Other [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of period	10,673	9,672
Charge- offs	(52)	(90)
Recoveries	2	3
Net charge- offs	(50)	(87)
Provisions charged to operations	423	246
Balance at end of period	11,046	9,831
Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of period	13,151	15,334
Charge- offs	(70)	(156)
Recoveries	67	13
Net charge- offs	(3)	(143)
Provisions charged to operations	1,261	(406)
Balance at end of period	14,409	14,785
Consumer Non-real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of period	3,065	2,793
Charge- offs	(120)	(250)
Recoveries	71	80
Net charge- offs	(49)	(170)
Provisions charged to operations	56	76
Balance at end of period	3,072	2,699
Other Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of period	2,423	2,481
Recoveries	35	12
Net charge- offs	35	12
Provisions charged to operations	(50)	(157)
Balance at end of period	2,408	2,336
Acquired Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of period	1,461	1,446
Charge- offs	(26)	(27)
Recoveries	4	18
Net charge- offs	(22)	(9)
Provisions charged to operations	(737)	(17)
Balance at end of period	$ 702	$ 1,420

Loans and Allowance for Loan_11

Loans and Allowance for Loan Losses - Allowance for Loan Losses Outstanding by Impairment Methodology (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	$ 9,628	$ 8,259
Collectively evaluated for impairment	43,287	43,130
Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	986	669
Collectively evaluated for impairment	5,669	5,659
Real Estate [Member] | Non-residential Real Estate Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	1,024	1,119
Collectively evaluated for impairment	10,338	9,908
Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	457	505
Collectively evaluated for impairment	2,804	2,756
Real Estate [Member] | Residential Real Estate All Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	3,691	3,413
Collectively evaluated for impairment	7,355	7,260
Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	3,069	2,114
Collectively evaluated for impairment	11,340	11,037
Consumer Non-real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	375	374
Collectively evaluated for impairment	2,697	2,691
Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	26	65
Collectively evaluated for impairment	2,382	2,358
Acquired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collectively evaluated for impairment	$ 702	$ 1,461

Loans and Allowance for Loan_12

Loans and Allowance for Loan Losses - Loans Outstanding by Impairment Methodology (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	$ 129,244	$ 118,356
Collectively evaluated for impairment	4,906,338	4,850,240
Loans Acquired with Deteriorated Credit Quality [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans acquired with deteriorated credit quality	6,920	7,380
Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	26,281	17,846
Collectively evaluated for impairment	612,738	608,775
Real Estate [Member] | Non-residential Real Estate Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	26,695	25,333
Collectively evaluated for impairment	1,163,074	1,120,795
Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	8,705	9,026
Collectively evaluated for impairment	324,961	319,676
Real Estate [Member] | Residential Real Estate All Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	21,883	21,285
Collectively evaluated for impairment	819,550	806,219
Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	28,722	19,432
Collectively evaluated for impairment	1,297,882	1,264,222
Consumer Non-real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	2,875	3,093
Collectively evaluated for impairment	324,131	323,769
Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	26	209
Collectively evaluated for impairment	142,394	141,700
Acquired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	14,057	22,132
Collectively evaluated for impairment	221,608	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	$ 6,920	$ 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	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Noncash Investing And Financing Items [Abstract]
Other real estate owned	$ 591	$ 402
Repossessed assets	301	220
Total	$ 892	$ 622

Intangible Assets - Summary of

Intangible Assets - Summary of Intangible Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 31,998	$ 32,003
Accumulated Amortization	(16,297)	(15,533)
Net Carrying Amount	15,701	16,470
Core Deposit Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	25,907	25,907
Accumulated Amortization	(11,785)	(11,113)
Net Carrying Amount	14,122	14,794
Customer Relationship Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	5,699	5,699
Accumulated Amortization	(4,202)	(4,115)
Net Carrying Amount	1,497	1,584
Mortgage Servicing Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	392	397
Accumulated Amortization	(310)	(305)
Net Carrying Amount	$ 82	$ 92

Intangible Assets - Summary o_2

Intangible Assets - Summary of Goodwill by Business Segment (Detail) $ in Thousands	Mar. 31, 2019USD ($)
Goodwill [Line Items]
Balance at beginning and end of period	$ 79,749
Balance at beginning and end of period	79,749
Metropolitan Banks [Member]
Goodwill [Line Items]
Balance at beginning and end of period	13,767
Community Banks [Member]
Goodwill [Line Items]
Balance at beginning and end of period	59,894
Other Financial Services [Member]
Goodwill [Line Items]
Balance at beginning and end of period	5,464
Executive, Operations & Support [Member]
Goodwill [Line Items]
Balance at beginning and end of period	$ 624

Leases - Additional Information

Leases - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Leases [Abstract]
Rent expense for operating leases	$ 357,000	$ 381,000
Right of use lease asset	$ 4,300,000
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	banf:AccruedInterestReceivableAndOtherAssetsMember
Operating lease liability	$ 4,300,000
Operating Lease, Liability, Statement of Financial Position [Extensible List]	banf:AccruedInterestPayableAndOtherLiabilitiesMember
Operating lease weighted-average remaining lease term	4 years 4 months 24 days
Operating lease weighted-average discount rate	3.60%
Operating lease revenue	$ 1,500,000

Leases - Schedule of Maturity o

Leases - Schedule of Maturity of Operating Lease Liabilities (Detail) $ in Thousands	Mar. 31, 2019USD ($)
Leases [Abstract]
2019 (nine months)	$ 97
2020	1,024
2021	150
2022	1,288
2023	955
Thereafter	737
Operating Lease Liability	$ 4,251

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	Mar. 31, 2019USD ($)
Leases [Abstract]
2019 (nine months)	$ 3,126
2020	2,524
2021	1,624
2022	973
2023	509
Total Future Minimum Lease Payments	$ 8,756

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 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	6,400,000
Shares for future grants	265,470
Stock option plan termination date	Dec. 31, 2019
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	520,000
Shares for future grants	40,000
Stock option plan termination date	Dec. 31, 2019
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, 2019
Number of shares authorized for issuance under deferred compensation plan	222,220
Number of shares of common stock distributed	8,362	2,842

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Activity Under Stock Option Plan (Detail) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 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	(5,500)
Options canceled, forfeited, or expired | shares	(22,500)
Outstanding at ending period - Options | shares	1,228,700
Exercisable at ending period - Options | shares	613,700
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	28.35
Options cancelled, forfeited, or expired - Wgtd. Avg. Exercise Price | $ / shares	51.83
Outstanding at ending period - Wgtd. Avg. Exercise Price | $ / shares	28.93
Exercisable at ending period - Wgtd. Avg. Exercise Price | $ / shares	$ 21.78
Outstanding at ending period - Wgtd. Avg. Remaining Contractual Term, years	9 years 4 months 20 days
Exercisable at ending period - Wgtd. Avg. Remaining Contractual Term, years	6 years 11 months 23 days
Outstanding at ending period - Aggregate Intrinsic Value | $	$ 28,536
Exercisable at ending period - Aggregate Intrinsic Value | $	$ 18,639

Stock-Based Compensation - Opti

Stock-Based Compensation - Options Exercised Under Stock Option Plan (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award Options Additional Disclosures [Abstract]
Total intrinsic value of options exercised	$ 145	$ 2,860
Cash received from options exercised	156	1,233
Tax benefit realized from options exercised	$ 37	$ 729

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock-Based Employee Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Labor And Related Expense [Abstract]
Stock-based compensation expense	$ 174	$ 306
Tax benefit	44	78
Stock-based compensation expense, net of tax	$ 130	$ 228

Stock-Based Compensation - Unea

Stock-Based Compensation - Unearned Stock-based Compensation Expense (Detail) $ in Thousands	Mar. 31, 2019USD ($)
Share Based Compensation [Abstract]
Unearned stock-based compensation expense	$ 3,437

Stock-Based Compensation - Assu

Stock-Based Compensation - Assumptions Used for Computing Stock-Based Compensation Expense (Detail) - $ / shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 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%	23.18%
Expected term	10 years	10 years

Stock - Based Compensation - Su

Stock - Based Compensation - Summary of Accumulated Stock Units (Detail) - $ / shares	Mar. 31, 2019	Dec. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Accumulated stock units	137,543	143,347
Average price	$ 25.70	$ 24.91

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Shares Repurchased Under Stock Purchase Program (Detail) - shares	Mar. 31, 2019	Mar. 31, 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	Mar. 31, 2019USD ($)
Parent Company [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital Amount	$ 911,073
Total Capital To Risk Weighted Assets Actual Ratio	16.32%
Capital Required For Capital Adequacy Amount	$ 446,687
Capital Required For Capital Adequacy to Risk Weighted Assets Ratio	8.00%
Capital With Capital Conservation Buffer Amount	$ 586,277
Capital With Capital Conservation To Risk Based Weighted Assets Buffer Ratio	10.50%
Common Equity Tier 1 Risk Based Capital Amount	$ 832,158
Common Equity Tier 1 Risk Based Capital To Risk Weighted Assets Ratio	14.90%
Common Equity Tier 1 Risk Based Capital Required For Capital Adequacy Amount	$ 251,262
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	$ 390,852
Common Equity Tier 1 Risk Based Capital With Capital Conservation Buffer To Risk Weighted Assets Ratio	7.00%
Tier 1 Risk Based Capital Amount	$ 858,158
Tier 1 Risk Based Capital To Risk Weighted Assets Ratio	15.37%
Tier 1 Risk Based Capital Required For Capital Adequacy Amount	$ 335,016
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	$ 474,605
Tier 1 Risk Based Capital With Capital Conservation Buffer To Risk Weighted Assets Ratio	8.50%
Tier 1 Capital Amount	$ 858,158
Tier 1 Capital To Average Assets Ratio	11.38%
Tier 1 Capital Required For Capital Adequacy Amount	$ 301,620
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	$ 788,443
Total Capital To Risk Weighted Assets Actual Ratio	14.14%
Capital Required For Capital Adequacy Amount	$ 445,937
Capital Required For Capital Adequacy to Risk Weighted Assets Ratio	8.00%
Capital With Capital Conservation Buffer Amount	$ 585,292
Capital With Capital Conservation To Risk Based Weighted Assets Buffer Ratio	10.50%
Capital Required To Be Well Capitalized Amount	$ 557,421
Capital Required To Be Well Capitalized To Risk Weighted Assets Ratio	10.00%
Common Equity Tier 1 Risk Based Capital Amount	$ 715,528
Common Equity Tier 1 Risk Based Capital To Risk Weighted Assets Ratio	12.84%
Common Equity Tier 1 Risk Based Capital Required For Capital Adequacy Amount	$ 250,839
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	$ 390,194
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	$ 362,323
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	$ 735,528
Tier 1 Risk Based Capital To Risk Weighted Assets Ratio	13.20%
Tier 1 Risk Based Capital Required For Capital Adequacy Amount	$ 334,452
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	$ 473,808
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	$ 445,937
Tier 1 Risk Based Capital Required To Be Well Capitalized To Risk Weighted Assets Ratio	8.00%
Tier 1 Capital Amount	$ 735,528
Tier 1 Capital To Average Assets Ratio	9.77%
Tier 1 Capital Required For Capital Adequacy Amount	$ 301,212
Tier 1 Capital Required For Capital Adequacy To Average Assets Ratio	4.00%
Tier 1 Capital Required To Be Well Capitalized Amount	$ 376,514
Tier 1 Capital Required To Be Well Capitalized To Average Assets Ratio	5.00%

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2019USD ($)
2016 [Member]
Stockholders Equity [Line Items]
Implementation of the capital conservation buffer, Percentage	0.625%
Capital conservation buffer implementation phase-in period	4 years
2019 [Member]
Stockholders Equity [Line Items]
Capital Conservation Buffer Maximum Level	2.50%
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
	Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share Reconciliation [Abstract]
Income available to common stockholders	$ 31,837	$ 29,620
Income available to common stockholders plus assumed exercises of stock options	$ 31,837	$ 29,620
Income available to common stockholders - Shares	32,612,399	32,574,251
Dilutive effect of stock options - Shares	680,453	743,493
Income available to common stockholders plus assumed exercises of stock options - Shares	33,292,852	33,317,744
Income available to common stockholders - Per Share Amount	$ 0.98	$ 0.91
Income available to common stockholders plus assumed exercises of stock options - Per Share Amount	$ 0.96	$ 0.89

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
	Mar. 31, 2019	Mar. 31, 2018
Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Abstract]
Shares	180,000	113,278

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value of Financial Assets and Liabilities Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	$ 723,655	$ 770,704
Derivative assets	51	252
Derivative liabilities	49	238
U.S. Treasuries [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	652,750	697,466
U.S. Federal Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	27,954	29,919
Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	15,712	15,908
States and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	27,239	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	652,750	697,466
Level 2 Inputs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	51	252
Derivative liabilities	49	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	27,954	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	2,311	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	27,239	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	$ 13,401	$ 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	3 Months Ended	12 Months Ended
	Mar. 31, 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	(39)	(1,037)
Total unrealized (losses) gains	(3)	13
Balance at the end of the period	$ 13,401	$ 13,443

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	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	Mar. 31, 2019	Dec. 31, 2018
Equity Securities [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Total Fair Value	$ 9,239	$ 7,521
Impaired Loans (Less Specific Allowance) [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Total Fair Value	36,160	34,396
Repossessed Assets [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Total Fair Value	184	183
Other Real Estate Owned [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Total Fair Value	$ 560	$ 4,683

Fair Value Measurements - Estim

Fair Value Measurements - Estimated Fair Values of Company's Financial Instruments (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
FINANCIAL ASSETS
Securities held for investment, Carrying Amount	$ 1,217	$ 1,428
Loans, net of allowance for loan losses, Carrying Amount	4,989,587	4,924,587
Securities held for investment, Fair Value	1,223	1,433
Loans held for sale, Fair Value	7,719	8,174
FINANCIAL LIABILITIES
Deposits, Carrying Amount	6,706,386	6,605,495
Short-term borrowings, Carrying Amount	5,200	1,675
Junior subordinated debentures, Carrying Amount	26,804	26,804
OFF-BALANCE SHEET FINANCIAL INSTRUMENTS
Loan commitments, Fair Value	2,219	2,158
Letters of credit, Fair Value	410	421
Level 2 Inputs [Member]
FINANCIAL ASSETS
Cash and cash equivalents, Carrying Amount	1,477,405	1,424,255
Securities held for investment, Carrying Amount	717	928
Loans held for sale, Carrying Amount	7,719	8,174
Cash and cash equivalents, Fair Value	1,477,405	1,424,255
Securities held for investment, Fair Value	723	933
Loans held for sale, Fair Value	7,719	8,174
FINANCIAL LIABILITIES
Deposits, Carrying Amount	6,706,386	6,605,495
Short-term borrowings, Carrying Amount	5,200	1,675
Junior subordinated debentures, Carrying Amount	26,804	26,804
Deposits, Fair Value	6,816,792	6,713,542
Short-term borrowings, Fair Value	5,200	1,675
Junior subordinated debentures, Fair Value	29,131	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	4,989,587	4,924,587
Securities held for investment, Fair Value	500	500
Loans, net of allowance for loan losses, Fair Value	$ 4,988,322	$ 4,901,159

Segment Information - Additiona

Segment Information - Additional Information (Detail)	3 Months Ended
	Mar. 31, 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
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Segment Reporting Information [Line Items]
Net interest income (expense)	$ 66,903	$ 63,035
Noninterest income	32,001	30,110
Income before taxes	41,014	36,941
Total Assets	7,709,000		$ 7,574,258
Operating Segments [Member] | Metropolitan Banks [Member]
Segment Reporting Information [Line Items]
Net interest income (expense)	21,353	20,304
Noninterest income	4,209	3,941
Income before taxes	15,369	14,736
Total Assets	2,763,523		2,743,876
Operating Segments [Member] | Community Banks [Member]
Segment Reporting Information [Line Items]
Net interest income (expense)	43,407	41,382
Noninterest income	14,885	13,953
Income before taxes	28,045	26,348
Total Assets	4,995,379		4,892,946
Operating Segments [Member] | Other Financial Services [Member]
Segment Reporting Information [Line Items]
Net interest income (expense)	1,171	1,475
Noninterest income	9,873	9,624
Income before taxes	4,499	5,043
Total Assets	69,430		84,706
Operating Segments [Member] | Executive, Operations & Support [Member]
Segment Reporting Information [Line Items]
Net interest income (expense)	972	(126)
Noninterest income	35,521	32,194
Income before taxes	25,023	19,915
Total Assets	912,166		861,782
Eliminations [Member]
Segment Reporting Information [Line Items]
Noninterest income	(32,487)	(29,602)
Income before taxes	(31,922)	$ (29,101)
Total Assets	$ (1,031,498)		$ (1,009,052)

Subsequent Event - Additional I

Subsequent Event - Additional Information (Detail) - Pegasus Bank [Member] - USD ($) $ in Millions	Apr. 23, 2019	Dec. 31, 2018
Subsequent Event [Line Items]
Total assets acquired		$ 639.1
Loans		367.4
Deposits		$ 595.3
Subsequent Event [Member]
Subsequent Event [Line Items]
Business acquisition, date of agreement	Apr. 23, 2019
Contract price	$ 122