BancFirst (BANF) 10-K 26 Feb 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2018	Jan. 31, 2019	Jun. 30, 2018
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Trading Symbol	BANF
Entity Registrant Name	BANCFIRST CORP /OK/
Entity Central Index Key	760,498
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		32,612,788
Entity Public Float			$ 1,122,037,373

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
ASSETS
Cash and due from banks	$ 228,431	$ 216,104
Interest-bearing deposits with banks	1,195,824	1,541,771
Federal funds sold		700
Securities held for investment (fair value: $1,433 and $2,303, respectively)	1,428	2,292
Securities available for sale at fair value	770,704	461,999
Loans held for sale	8,174	6,173
Loans (net of unearned interest)	4,975,976	4,721,995
Allowance for loan losses	(51,389)	(51,666)
Loans, net of allowance for loan losses	4,924,587	4,670,329
Premises and equipment, net	174,362	134,088
Other real estate owned	6,690	4,136
Intangible assets, net	16,470	11,082
Goodwill	79,749	54,042
Accrued interest receivable and other assets	167,839	150,440
Total assets	7,574,258	7,253,156
Deposits:
Noninterest-bearing	2,613,876	2,550,150
Interest-bearing	3,991,619	3,864,895
Total deposits	6,605,495	6,415,045
Short-term borrowings	1,675	900
Accrued interest payable and other liabilities	37,495	29,623
Junior subordinated debentures	26,804	31,959
Total liabilities	6,671,469	6,477,527
Commitments and contingent liabilities (Note 19)
Stockholders' equity:
Common stock, $1.00 par, 40,000,000 shares authorized; shares issued and outstanding: 32,603,926 and 31,894,563, respectively	32,604	31,895
Capital surplus	149,709	107,481
Retained earnings	722,615	638,580
Accumulated other comprehensive loss, net of income tax of $(731) and $(795), respectively	(2,139)	(2,327)
Total stockholders' equity	902,789	775,629
Total liabilities and stockholders' equity	7,574,258	7,253,156
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	Dec. 31, 2018	Dec. 31, 2017
Securities, fair value	$ 1,433	$ 2,303
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	40,000,000	40,000,000
Common stock, shares issued	32,603,926	31,894,563
Common stock, shares outstanding	32,603,926	31,894,563
Accumulated other comprehensive loss, tax expense (benefit)	$ (731)	$ (795)
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 - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
INTEREST INCOME
Loans, including fees	$ 263,093	$ 222,022	$ 204,467
Securities:
Taxable	8,808	7,171	5,229
Tax-exempt	609	737	964
Federal funds sold	291	61	1
Interest-bearing deposits with banks	30,403	18,077	7,908
Total interest income	303,204	248,068	218,569
INTEREST EXPENSE
Deposits	40,462	18,790	12,638
Short-term borrowings	95	17	7
Junior subordinated debentures	2,171	2,122	2,096
Total interest expense	42,728	20,929	14,741
Net interest income	260,476	227,139	203,828
Provision for loan losses	3,802	8,512	11,519
Net interest income after provision for loan losses	256,674	218,627	192,309
NONINTEREST INCOME
Securities transactions (includes accumulated other comprehensive income reclassifications of $9, $(17) and $15, respectively)	47	4,060	(59)
Income from sales of loans	2,902	2,921	2,825
Insurance commissions	18,926	16,811	15,559
Cash management	13,123	11,155	10,616
Gain (loss) on sale of other assets	575	(60)	46
Other	5,950	5,629	5,182
Total noninterest income	125,199	118,070	107,032
NONINTEREST EXPENSE
Salaries and employee benefits	139,547	125,149	119,662
Occupancy, net	13,491	12,591	12,313
Depreciation	10,537	9,603	10,114
Amortization of intangible assets	3,009	2,188	2,269
Data processing services	4,956	4,654	4,796
Net expense (income) from other real estate owned	239	421	(747)
Marketing and business promotion	8,028	7,389	7,236
Deposit insurance	2,427	2,261	2,904
Other	39,887	36,136	32,857
Total noninterest expense	222,121	200,392	191,404
Income before taxes	159,752	136,305	107,937
Income tax expense	33,938	49,866	37,263
Net income	$ 125,814	$ 86,439	$ 70,674
NET INCOME PER COMMON SHARE
Basic	$ 3.85	$ 2.72	$ 2.27
Diluted	$ 3.76	$ 2.65	$ 2.22
OTHER COMPREHENSIVE INCOME
Unrealized losses on securities, net of tax of $139, $861 and $897, respectively	$ (423)	$ (2,431)	$ (1,424)
Reclassification adjustment for (gains)/losses included in net income, net of tax of $2, $(7) and $6, respectively	(7)	10	(9)
Other comprehensive loss, net of tax of $(64), $854 and $903, respectively	(430)	(2,421)	(1,433)
Comprehensive income	125,384	84,018	69,241
Trust Revenue [Member]
NONINTEREST INCOME
Revenue	12,829	12,002	10,630
Service Charges on Deposits [Member]
NONINTEREST INCOME
Revenue	$ 70,847	$ 65,552	$ 62,233

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Securities transactions accumulated other comprehensive income reclassifications	$ 9	$ (17)	$ 15
Unrealized losses on securities, tax	139	861	897
Reclassification adjustment for gains included in net income, tax	2	(7)	6
Other comprehensive gain (loss), tax	$ (64)	$ 854	$ 903

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	COMMON STOCK [Member]	CAPITAL SURPLUS [Member]	RETAINED EARNINGS [Member]	ACCUMULATED OTHER COMPREHENSIVE INCOME [Member]
Balance at beginning of period, Shares at Dec. 31, 2015		31,194,892
Balance at beginning of period at Dec. 31, 2015		$ 31,194	$ 87,268	$ 535,521	$ 1,527
Shares issued for stock options, Shares		626,978
Shares issued for stock options, Value		$ 628	9,305
Net income	$ 70,674			70,674
Net change	$ (1,433)				(1,433)
Tax effect of stock options			3,521
Dividends on common stock				(23,124)
Stock-based compensation arrangements			1,636
Shares acquired and canceled, Shares		(200,000)
Shares acquired and canceled, Value		$ (200)		(5,423)
Balance at end of period, Shares at Dec. 31, 2016	31,621,870	31,621,870
Balance at end of period at Dec. 31, 2016	$ 711,094	$ 31,622	101,730	577,648	94
Shares issued for stock options, Shares		272,693
Shares issued for stock options, Value		$ 273	4,571
Net income	86,439			86,439
Net change	$ (2,421)				(2,421)
Dividends on common stock				(25,507)
Stock-based compensation arrangements			1,180
Balance at end of period, Shares at Dec. 31, 2017	31,894,563	31,894,563
Balance at end of period at Dec. 31, 2017	$ 775,629	$ 31,895	107,481	638,580	(2,327)
Shares issued for stock options, Shares		127,816
Shares issued for stock options, Value		$ 127	2,111
Shares issued for acquisitions, Shares		732,811
Shares issued for acquisitions, Value		$ 733	38,765
Net income	125,814			125,814
Net change	$ (430)				(430)
Dividends on common stock				(33,398)
Stock-based compensation arrangements			1,352
Shares acquired and canceled, Shares		(151,264)
Shares acquired and canceled, Value		$ (151)		(7,763)
Cumulative effect of change in accounting principle				(618)	618
Balance at end of period, Shares at Dec. 31, 2018	32,603,926	32,603,926
Balance at end of period at Dec. 31, 2018	$ 902,789	$ 32,604	$ 149,709	$ 722,615	$ (2,139)

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
RETAINED EARNINGS [Member]
Dividend on common stock	$ 1.02	$ 0.80	$ 0.74

Consolidated Statements of Cash

Consolidated Statements of Cash Flow $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 125,814	$ 86,439	$ 70,674
Adjustments to reconcile to net cash provided by operating activities:
Provision for loan losses	3,802	8,512	11,519
Depreciation and amortization	13,546	11,791	12,383
Net amortization of securities premiums and discounts	(421)	(148)	128
Realized securities (gains) losses	(47)	(4,060)	59
Gain on sales of loans	(2,902)	(2,921)	(2,825)
Cash receipts from the sale of loans originated for sale	187,461	211,569	189,620
Cash disbursements for loans originated for sale	(186,632)	(205,574)	(182,425)
Deferred income tax provision (benefit)	3,155	4,383	(2,048)
(Gain)/loss on other assets	(596)	46	(1,252)
Increase in interest receivable	(3,390)	(3,284)	(1,497)
Increase in interest payable	1,179	366	69
Amortization of stock-based compensation arrangements	1,352	1,180	1,636
Excess tax benefit from stock-based compensation arrangements	(1,112)	(2,601)
Other, net	(10,063)	(1,173)	(5,500)
Net cash provided by operating activities	131,146	104,525	90,541
INVESTING ACTIVITIES
Net cash received from acquisitions, net of cash paid	6,248
Net decrease/ (increase) in federal funds sold	23,548		(700)
Purchases of held for investment securities	(225)	(220)	(838)
Purchases of available for sale securities	(465,684)	(84,109)	(223,558)
Proceeds from maturities, calls and paydowns of held for investment securities	1,089	2,293	5,260
Proceeds from maturities, calls and paydowns of available for sale securities	126,909	78,682	300,156
Proceeds from sales of available for sale securities	31,285
Purchase of equity securities	(3,190)	(1,668)	(1,097)
Proceeds from paydowns and sales of equity securities	1,484	5,793	670
Net change in loans	49,354	(331,362)	(176,594)
Purchases of premises, equipment and computer software	(51,863)	(18,007)	(10,835)
Other, net	(3,890)	4,038	9,519
Net cash used in investing activities	(284,935)	(344,560)	(98,017)
FINANCING ACTIVITIES
Net change in deposits	(139,510)	166,988	274,699
Net change in short-term borrowings	775	400
Issuance of common stock in connection with stock options, net	2,238	4,844	13,354
Common stock acquired	(7,914)		(5,523)
Redemption of Junior Subordinated debentures	(5,155)
Cash dividends paid	(30,265)	(24,783)	(22,770)
Net cash (used in) provided by financing activities	(179,831)	147,449	259,760
Net (decrease)/increase in cash, due from banks and interest-bearing deposits	(333,620)	(92,586)	252,284
Cash, due from banks and interest-bearing deposits at the beginning of the period	1,757,875	1,850,461	1,598,177
Cash, due from banks and interest-bearing deposits at the end of the period	1,424,255	1,757,875	1,850,461
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid during the period for interest	41,549	20,563	14,673
Cash paid during the period for income taxes	27,952	41,058	32,700
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	$ 9,826	$ 6,693	$ 5,969

Description of Business and Sum

Description of Business and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
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 the significant accounting policies follows. Nature of Operations BancFirst Corporation is an Oklahoma business corporation and a financial holding company under federal law. It conducts virtually all of its operating activities through its principal wholly-owned subsidiary, BancFirst (the “Bank” or “BancFirst”), a state-chartered bank headquartered in Oklahoma City, Oklahoma. The Bank provides a wide range of retail and commercial banking services, including: commercial, real estate, agricultural and consumer lending; depository and funds transfer services; collections; safe deposit boxes; cash management services; retail brokerage services; and other services tailored for both individual and corporate customers. The Bank also offers trust services and acts as executor, administrator, trustee, transfer agent and in various other fiduciary capacities. Through its Technology and Operations Center, the Bank provides item processing, research and other correspondent banking services to financial institutions and governmental units. The Company’s wholly-owned subsidiary, BancFirst Insurance Services, Inc., an independent insurance agency, offers a variety of commercial and personal insurance products. In addition, the Company’s wholly-owned subsidiary, Council Oak Partners, LLC, an Oklahoma limited liability company, engages in investing activities. Basis of Presentation The accompanying 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 consolidated financial statements. Certain amounts from 2017 and 2016 have been reclassified to conform to the 2018 presentation. These reclassifications were not material to the Company’s 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. Securities The Company invests in debt securities. Any sales of debt securities are for the purpose of executing the Company’s asset/liability management strategy, eliminating a perceived credit risk in a specific security or providing liquidity. Debt securities that are being held for indefinite periods of time, or that may be sold as part of the Company’s asset/liability management strategy, to provide liquidity or for other reasons, are classified as available for sale and are stated at estimated fair value. Unrealized gains or losses on debt securities available for sale are reported as a component of stockholders’ equity, net of income tax. Gains or losses from sales of debt securities are based upon the book values of the specific debt securities sold. Debt securities for which the Company has the intent and ability to hold to maturity are classified as held for investment and are stated at cost, adjusted for amortization of premiums and accretion of discounts computed under the interest method. The Company reviews its portfolio of securities for impairment at least quarterly. Impairment is considered to be other-than-temporary if it is likely that all amounts contractually due will not be received for debt securities. When impairment is considered other-than-temporary, the cost basis of the security is written down to fair value, with the impairment charge included in earnings. In evaluating whether the impairment is temporary or other-than-temporary, the Company considers, among other things, the period of time the security has been in an unrealized loss position, and whether the Company has the intent and ability to hold a security for a period of time sufficient to allow for any anticipated recovery in fair value. The Company does not engage in securities trading activities. 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. For periods prior to January 1, 2018, equity securities were classified as available-for-sale and stated at fair value with unrealized gains and losses reported as a separate component of accumulated other comprehensive income (loss), net of tax. Equity securities are reported in other assets on the balance sheet. The Company reviews its portfolio of equity securities for impairment at least quarterly. Loans The lending function is governed by written policies and procedures, as determined by senior management and approved by the Board of Directors. The policies and procedures set the standards for lending in each major loan category by collateral type and use of loan proceeds. The objectives of these policies and procedures are to identify profitable markets, determine appropriate risk tolerance levels for each type of loan, establish limits for loan officer approval, set concentration limits, establish loan-to-value thresholds, set repayment terms and loan structure guidelines and adhere to documentation requirements. Interest rate risk is controlled by the use of variable rate provisions, the vast majority of which have a rate floor, limits on fixing rates for longer periods and the use of prepayment penalties. One-to-four family residential real estate loans are made in accordance with underwriting policies and are fully documented. Credit worthiness is assessed based on significant credit characteristics including credit history and residential and employment stability. These loans include first liens, junior liens and home equity lines of credit. The composition of this portfolio is primarily first liens, which comprise approximately 82% of the portfolio, with junior liens comprising approximately 9%, and home equity lines of credit comprising approximately 9%. The Company does not engage in any hybrid loan programs. In addition, the Company does not have any exposure to loans with negative amortization, interest rate carryover or discounting of the initial rates (teaser rates). Loans originated within the Company are stated at the principal amount outstanding, net of unearned interest, loan fees and allowance for loan losses. Interest on all performing loans is recognized, on a simple interest basis, based upon the principal amount outstanding. A loan is placed on nonaccrual status when, in the opinion of management, the future collectability of interest and/or principal is not probable. When interest accrual is discontinued, all unpaid accrued interest is reversed. Interest income is recognized on certain of these loans on a cash basis if the full collection of the remaining principal balance is reasonably expected. Otherwise, interest income is not recognized until the principal balance is fully collected. See Note (5) for loan disclosures. An updated appraisal of the collateral is obtained when a loan is first identified as a problem loan. Appraisals are reviewed annually and are updated as needed, or are updated more frequently if significant changes are believed to have occurred in the collateral or market conditions. Appraisals of other real estate owned are also reviewed and updated consistent with this policy. When a loan deteriorates to the point that the account officer or the Loan Committee concludes it no longer represents a viable asset, it will be charged off. Similarly, any portion of a loan that is deemed to no longer be a viable asset will be charged off. A loan will not be charged off unless such action has been approved by the branch President. Acquired Loans Loans acquired through business combinations since December 2009 are required to be carried at fair value as of the date of the combination. Loans that would have a general allowance for loan losses or have specific evidence of deterioration of credit quality since origination are adjusted to fair value and any allowance for loan losses is eliminated. The difference between the fair value of loans which do not have specific evidence of deterioration of credit quality since origination and their principal balance is recognized in interest income on a level-yield method over the life of the loans. For loans which it is probable, at acquisition, that the Company will be unable to collect all contractually required payments (as determined by the present value of expected future cash flows), the difference between the undiscounted cash flows expected at acquisition and the investment in the loan, or the “accretable yield,” is recognized in interest income on a level-yield method over the life of the loan. Contractually required payments for interest and principal that exceed the undiscounted cash flows expected at acquisition, or the “nonaccretable difference,” are not recognized as yield adjustments or as loss accruals or valuation allowances. Increases in expected cash flows subsequent to the initial investment are recognized prospectively through adjustment of the yield on the loan over its remaining life. Decreases in expected cash flows are recognized as impairments. Any probable loss due to subsequent credit deterioration of the loans since acquisition is provided for in the allowance for loan losses. 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 the 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 carried at the lower of cost or fair value. Gains or losses recognized upon the sale of the loans are determined on a specific identification basis. The Company does not sell residential mortgage loans with recourse other than obligations under standard representations and warranties or for fraud. These obligations relate to loan performance for the life of the loan. The amount of loans repurchased since the inception of the program is not considered to be material, and therefore, no reserve has been required. Allowance for Loan Losses The allowance for loan losses is an estimate of probable credit losses related to specifically identified loans and for losses inherent in the portfolio that have been incurred as of the balance sheet date. The allowance for loan losses is increased by provisions charged to operating expense and is reduced by net loan charge-offs. The amount of the allowance for loan losses is based on past loan loss experience, evaluations of known impaired loans, levels of adversely graded loans, general economic conditions and other environmental factors. Loans are considered impaired when, based on current information and events, it is probable the Company will be unable to collect all amounts due in accordance with the original contractual terms of the loan agreement, including scheduled principal and interest payments. Impairment is evaluated in aggregate for smaller-balance loans of a similar nature and on an individual loan basis for other loans. If a loan is impaired, a specific allowance is provided, if necessary, so that the loan is reported net, at the present value of estimated future cash flows using the loan’s existing rate or at the fair value of collateral if repayment is expected primarily from the collateral. Interest payments on impaired loans are typically applied to principal unless collectability of the principal amount is reasonably assured, in which case interest is recognized on a cash basis. Impaired loans, or portions thereof, are charged off when deemed uncollectible. Nonaccrual Policy The Company does not accrue interest on (1) any loan upon which a default of principal or interest has existed for a period of 90 days or over unless the collateral margin or guarantor support are such that full collection of principal and interest are not in doubt, and an orderly plan for collection is in process; and (2) any other loan for which it is expected full collection of principal and interest is not probable. A nonaccrual loan may be restored to an accrual status when none of its principal and interest are past due and unpaid or otherwise becomes well secured and in the process of collection and when prospects for collection of future contractual payments are no longer in doubt. With the exception of a formal debt forgiveness agreement, no loan which has had principal charged-off shall be restored to accrual status unless the charged-off principal has been recovered. Premises and Equipment Premises and equipment are stated at cost, less accumulated depreciation. Depreciation is charged to operating expense and is computed using the straight-line method over the estimated useful lives of the assets. Maintenance and repairs are charged to expense as incurred while improvements are capitalized. Premises and equipment is tested for impairment if events or changes in circumstances occur that indicate that the carrying amount of any premises and equipment may not be recoverable. Impairment losses are measured by comparing the fair values of the premises and equipment with their recorded amounts. Premises that are identified to be sold are transferred to other real estate owned at the lower of their carrying amounts or their fair values less estimated costs to sell. Any losses on premises identified to be sold are charged to operating expense. When premises and equipment are transferred to other real estate owned, sold, or otherwise retired, the cost and applicable accumulated depreciation are removed from the respective accounts and any resulting gains or losses are reported in the statement of comprehensive income. Other Real Estate Owned Other real estate owned consists of properties acquired through foreclosure proceedings or acceptance of a deed in lieu of foreclosure, and premises held for sale. These properties are carried at the lower of the book values of the related loans or fair values based upon appraisals, less estimated costs to sell. Losses arising at the time of reclassification of such properties from loans to other real estate owned are charged directly to the allowance for loan losses. Any losses on premises identified to be sold are charged to operating expense at the time of transfer from premises to other real estate owned. Losses from declines in value of the properties subsequent to classification as other real estate owned are charged to operating expense. Intangible Assets and Goodwill Core deposit intangibles are amortized on a straight-line basis over the estimated useful lives of seven to ten years and customer relationship intangibles are amortized on a straight-line basis over the estimated useful life of three to eighteen years. Mortgage servicing rights are amortized based on current prepayment assumptions. Goodwill is not amortized, but is evaluated at a reporting unit level at least annually for impairment, or more frequently if other indicators of impairment are present. At least annually in the fourth quarter, intangible assets, excluding mortgage servicing rights, are evaluated for possible impairment. Impairment losses are measured by comparing the fair values of the intangible assets with their recorded amounts. Any impairment losses are reported in the statement of comprehensive income. Mortgage servicing rights are adjusted to fair value periodically, if impaired. Derivatives The Company recognizes all of its derivative instruments as assets or liabilities in the balance sheet at fair value and recognizes the realized and unrealized change in fair value in the statement of comprehensive income. Income is derived from a fixed pricing spread when customer hedge contracts are immediately offset with counterparty contracts as compensation for administrative costs and credit risk and recognized in other noninterest income. Insurance Commissions and Fees Commission revenue is recognized at the later of the billing date or the effective date of the related insurance policies for those accounts billed by the Agency. Commission revenue, for accounts that are directly billed by the insurance company to the insured, is recognized when determinable by the Agency, which is generally when such commissions are received. The Agency also receives contingent commissions from insurance companies as additional incentive for achieving specified premium volume goals and/or loss experience parameters relating to the insurance placed by the Agency. Contingent commissions from insurance companies are recognized when determinable, which is generally when such commissions are received. Stock-based Compensation The Company recognizes stock-based compensation as compensation expense in the statement of comprehensive income based on the fair value of the Company’s stock options on the measurement date, which, for the Company, is the date of the grant. 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. Income Taxes The Company files a consolidated income tax return with its subsidiaries. Federal and state income tax expense or benefit has been allocated to subsidiaries on a separate return basis. Deferred taxes are recognized under the balance sheet method based upon the future tax consequences of temporary differences between the carrying amounts and tax basis of assets and liabilities, using the tax rates expected to apply to taxable income in the periods when the related temporary differences are expected to be realized. Realization of deferred tax assets is dependent upon the generation of a sufficient level of future taxable income and recoverable taxes paid in prior years. Although realization is not assured, management believes it is more likely than not that all of the deferred tax assets will be realized. Earnings Per Common Share Basic earnings per common share is computed by dividing net income, less any preferred dividends requirement, by the weighted average of common shares outstanding. Diluted earnings per common share reflects the potential dilution that could occur if options, convertible securities or other contracts to issue common stock were exercised or converted into common stock or resulted in the issuance of common stock that then shared in the earnings of the Company. Comprehensive Income Comprehensive income includes all changes in stockholders’ equity during a period, except those resulting from transactions with stockholders. Besides net income, other components of the Company’s comprehensive income includes the after tax effect of changes in the net unrealized gain/loss on debt securities available for sale. Statement of Cash Flows For purposes of the statement of cash flows, the Company considers cash and due from banks and interest-bearing deposits with banks as cash equivalents. Recent Accounting Pronouncements Standards Adopted During Current Period: In February 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2018-2, Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. ASU 2018-2 allows a reclassification from accumulated other comprehensive income (loss) to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act. ASU 2018-2 is effective for fiscal years beginning after December 15, 2018 with early adoption permitted. The Company elected to early adopt the provisions of ASU 2018-2 and the amount to reclassify was immaterial to the Company’s financial statements. The Company’s policy is to release material stranded tax effects on a specific identification basis. In May 2017, the FASB issued ASU No. 2017-09, “Compensation – Stock Compensation (Topic 718): Scope of Modification Accounting.” The amendments in this update provide guidance about types of changes to the terms of conditions of share-based payment awards that would require an entity to apply modification accounting under ASC 718. ASU 2017-09 was adopted on January 1, 2018 and did not have a significant impact on the Company’s financial statements and no prior periods were adjusted. In January 2017, the FASB issued ASU No. 2017-04, “Intangibles – Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment.” ASU 2017-04 removes the second step of goodwill testing. ASU 2017-04 is effective for fiscal years beginning after December 31, 2019 with early adoption permitted. The Company elected to early adopt ASU 2017-4 and it did not have a significant impact on the Company’s financial statements. In January 2017, the FASB issued ASU No. 2017-01, “Business Combinations (Topic 805): Clarifying the Definition of a Business.” ASU 2017-01 clarifies the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of a business. ASU 2017-01 was adopted on January 1, 2018 and did not have a significant impact on the Company’s financial statements. In October 2016, the FASB issued ASU No. 2016-16, “Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory.” ASU 2016-16 provides guidance stating that an entity should recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. ASU 2016-16 was adopted on January 1, 2018 and did not have a significant impact on the Company’s financial statements and no prior periods were adjusted. In August 2016, the FASB issued ASU No. 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments.” ASU 2016-15 is intended to reduce the diversity in practice around how certain transactions are classified within the statement of cash flows. ASU 2016-15 was adopted on January 1, 2018 and did not have a significant impact on the Company’s financial statements. In January 2016, the FASB issued ASU No. 2016-01, “Financial Instruments – Overall (Subtopic 825-10).” ASU 2016-01 requires all equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) to be measured at fair value with changes in the fair value recognized through net income. The adoption of the guidance resulted in a $618,000 decrease to retained earnings and a $618,000 increase to accumulated other comprehensive income. Additional income of $48,900 was recorded in the consolidated statement of comprehensive income during 2018 as a result of changes to the accounting for equity investments. Further, the Company’s securities disclosures in Note (4) have been revised to exclude equity investments and fair value disclosures in Note (20) have incorporated the revised disclosure requirements for financial investments. In addition, equity securities of $5.7 million were reclassed from securities to other assets on the Company’s 2017 balance sheet to conform to the current presentation. ASU 2016-01 also emphasizes the existing requirement to use exit prices to measure fair value for disclosure purposes and clarifies that entities should not make use of a practicability exception in determining the fair value of loans. Accordingly, we refined the calculation used to determine the disclosed fair value of loans held for investment as part of adopting this standard. The refined calculation did not have a significant impact on fair value disclosures. In January 2014, the FASB issued ASU No. 2014-09, “Revenue from Contracts with Customers (Topic 606).” ASU 2014-09 implements a comprehensive new revenue recognition standard that will supersede substantially all existing revenue recognition guidance. The new standard’s core principle is that a company will recognize revenue when it transfers promised goods or services to customers in a manner that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. The guidance does not apply to revenue associated with financial instruments, including loans and securities that are accounted for under other GAAP, which comprises a significant portion of the Company’s revenue stream. ASU 2014-09 was adopted on January 1, 2018 and did not have a significant impact on the Company’s financial statements. 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. 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 models 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 Company expects to adopt the standard in the first quarter of 2020. In February 2016, the FASB issued ASU No. 2016-02, “Leases - (Topic 842).” ASU 2016-02 requires that lessees recognize on the balance sheet the assets and liabilities for the rights and obligations created by leases. The amendments are effective for annual periods, and interim reporting periods within those annual periods, beginning after December 15, 2018. The Company .

Recent Developments, Including

Recent Developments, Including Mergers and Acquisitions	12 Months Ended
	Dec. 31, 2018
Recent Developments Including Mergers And Acquisitions [Abstract]
Recent Developments, Including Mergers and Acquisitions	(2) RECENT DEVELOPMENTS, INCLUDING MERGERS AND ACQUISITIONS 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. On July 31, 2017, the Company completed a two-for-one stock split of the Company’s outstanding shares of common stock. The stock was payable in the form of a dividend on or about July 31, 2017 to shareholders of record of the outstanding common stock as of the close of business record date of July 17, 2017. Stockholders received one additional share for each share held on that date. This was the second stock split for the Company since going public. All share and per share amounts in these consolidated financial statements and related notes have been retroactively adjusted to reflect this stock split for all periods presented. Effective June 1, 2017, the Company organized a new wholly-owned captive insurance company named BancFirst Risk & Insurance Company. It insures certain risks of the Company and has entered into reinsurance agreements with a risk-sharing pool.

Cash, Due from Banks, Interest-

Cash, Due from Banks, Interest-Bearing Deposits and Federal Funds Sold	12 Months Ended
	Dec. 31, 2018
Cash And Cash Equivalents [Abstract]
Cash, Due from Banks, Interest-Bearing Deposits and Federal Funds Sold	(3) CASH, DUE FROM BANKS, INTEREST-BEARING DEPOSITS AND FEDERAL FUNDS SOLD The Company maintains accounts with the Federal Reserve Bank and various other financial institutions primarily for the purpose of holding excess liquidity and clearing cash items. It may also sell federal funds to certain of these institutions on an overnight basis. At December 31, 2018 and 2017, the Company had no significant concentrations of credit risk with other financial institutions. The Company maintained vault cash and funds on deposit with the Federal Reserve Bank, which is included in the table below. The Company is required, as a matter of law, to maintain a reserve balance in the form of vault cash or cash on deposit with the Federal Reserve Bank. The average amount of required reserves for each of the years ended December 31, 2018 and 2017 is included in the following table: December 31, 2018 2017 (Dollars in thousands) Vault cash and funds on deposit with the Federal Reserve Bank $ 1,299,872 $ 1,639,058 Average required Reserves 45,195 44,485

Securities

Securities	12 Months Ended
	Dec. 31, 2018
Investments Debt And Equity Securities [Abstract]
Securities	(4) 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 (Dollars in thousands) 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 December 31, 2017 Mortgage backed securities (1) $ 187 $ 10 $ — $ 197 States and political subdivisions 1,605 3 (2 ) 1,606 Other securities 500 — — 500 Total $ 2,292 $ 13 $ (2 ) $ 2,303 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 (Dollars in thousands) 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 December 31, 2017 U.S. treasuries $ 314,905 $ — $ (2,103 ) $ 312,802 U.S. federal agencies 89,098 82 (329 ) 88,851 Mortgage backed securities (1) 18,358 204 (586 ) 17,976 States and political subdivisions 41,937 554 (121 ) 42,370 Total $ 464,298 $ 840 $ (3,139 ) $ 461,999 (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. December 31, 2018 2017 Amortized Cost Estimated Fair Value Amortized Cost Estimated Fair Value (Dollars in thousands) Held for Investment Contractual maturity of debt securities: Within one year $ 495 $ 495 $ 1,036 $ 1,034 After one year but within five years 369 370 623 627 After five years but within ten years 562 565 625 633 After ten years 2 3 8 9 Total $ 1,428 $ 1,433 $ 2,292 $ 2,303 Available for Sale Contractual maturity of debt securities: Within one year $ 411,256 $ 410,327 $ 113,225 $ 112,974 After one year but within five years 313,416 311,924 289,038 287,058 After five years but within ten years 7,524 7,685 6,222 6,500 After ten years 41,378 40,768 55,813 55,467 Total debt securities $ 773,574 $ 770,704 $ 464,298 $ 461,999 The following is a detail of proceeds from sales and realized securities losses, on available for sale debt securities: Year Ended December 31, 2018 2017 2016 (Dollars Proceeds $ 31,285 $ — $ — Gross losses realized 109 — — Realized gains/losses on debt and equity securities are reported as securities transactions within the noninterest income section of the consolidated statement of comprehensive income. The following table is a summary of the Company’s book value of debt securities that were pledged as collateral for public funds on deposit, repurchase agreements and for other purposes as required or permitted by law: December 31, 2018 2017 (Dollars Book value of pledged securities $ 472,053 $ 440,069 The following table summarizes debt securities with unrealized losses, segregated by the duration of the unrealized loss, at December 31, 2018 and 2017 respectively: Less than 12 Months More than 12 Months Total Estimated Fair Value Unrealized Losses Estimated Fair Value Unrealized Losses Estimated Fair Value Unrealized Losses (Dollars in thousands) December 31, 2018 Held for Investment Mortgage backed securities $ — $ — $ 4 $ — $ 4 $ — Total $ — $ — $ 4 $ — $ 4 $ — Available for Sale U.S. treasuries $ 296,438 $ 90 $ 261,639 $ 3,434 $ 558,077 $ 3,524 U.S. federal agencies 1,705 7 27,035 153 28,740 160 Mortgage backed securities 1 — 13,444 573 13,445 573 States and political subdivisions 1,593 3 11,527 109 13,120 112 Total $ 299,737 $ 100 $ 313,645 $ 4,269 $ 613,382 $ 4,369 December 31, 2017 Held for Investment Mortgage backed securities $ — $ — $ 7 $ — $ 7 $ — States and political subdivisions 65 — 478 2 543 2 Total $ 65 $ — $ 485 $ 2 $ 550 $ 2 Available for Sale U.S. treasuries $ 283,302 $ 1,653 $ 29,500 $ 450 $ 312,802 $ 2,103 U.S. federal agencies 3,499 8 59,220 321 62,719 329 Mortgage backed securities 1 — 14,475 586 14,476 586 States and political subdivisions 21,300 114 585 7 21,885 121 Total $ 308,102 $ 1,775 $ 103,780 $ 1,364 $ 411,882 $ 3,139 Declines in the fair value of held for investment and available-for-sale debt securities below their cost that are deemed to be other than temporary are reflected in earnings as realized losses. In estimating other-than-temporary impairment losses, management considers, among other things, (i) the length of time and the extent to which the fair value has been less than cost, (ii) the financial condition and near-term prospects of the issuer and (iii) the intent and ability of the Company to retain its investment in the issuer for a period of time sufficient to allow for any anticipated recovery in fair value. Management has the ability and intent to hold the debt securities classified as held for investment until they mature, at which time the Company will receive full value for the debt securities. Furthermore, as of December 31, 2018 and 2017, the Company also had the ability and intent to hold the debt securities classified as available for sale for a period of time sufficient for a recovery of cost. The unrealized losses are due to increases in market interest rates over the yields available at the time the underlying debt securities were purchased. The fair value of those debt securities having unrealized losses is expected to recover as the securities approach their maturity date or repricing date, or if market yields for such investments decline. Management has no intent or requirement to sell before the recovery of the unrealized loss; therefore, no significant impairment loss was realized in the Company’s consolidated statement of comprehensive income.

Loans and Allowance for Loan Lo

Loans and Allowance for Loan Losses	12 Months Ended
	Dec. 31, 2018
Receivables [Abstract]
Loans and Allowance for Loan Losses	(5) LOANS AND ALLOWANCE FOR LOAN LOSSES The following is a schedule of loans outstanding by category: December 31, 2018 2017 Amount Percent Amount Percent (Dollars in thousands) Commercial and financial: Commercial and industrial $ 1,032,787 20.76 % $ 995,207 21.08 % Oil & gas production and equipment 94,729 1.90 95,574 2.02 Agriculture 136,313 2.74 141,249 2.99 State and political subdivisions: Taxable 76,211 1.53 73,827 1.56 Tax-exempt 48,415 0.97 48,626 1.03 Real estate: Construction 451,224 9.07 437,277 9.26 Farmland 219,241 4.41 195,162 4.13 One to four family residences 979,170 19.68 875,766 18.55 Multifamily residential properties 65,949 1.33 46,030 0.98 Commercial 1,506,937 30.28 1,487,927 31.51 Consumer 328,069 6.59 284,373 6.02 Other (not classified above) 36,931 0.74 40,977 0.87 Total loans $ 4,975,976 100.00 % $ 4,721,995 100.00 % 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 $60 million at December 31, 2018 and approximately $81 million at December 31, 2017. There are inherent risks associated with the Company’s lending activities. These risks include, among other things, the impact of changes in interest rates and changes in the economic conditions in the markets where the Company operates. Increases in interest rates and/or weakening economic conditions could adversely impact the ability of borrowers to repay outstanding loans or the value of the collateral securing these loans. The Company is also subject to various laws and regulations that affect its lending activities. Failure to comply with applicable laws and regulations could subject the Company to regulatory enforcement action that could result in the assessment of significant civil money penalties against the Company. As a lender, the Company faces the risk that a significant number of its borrowers will fail to pay their loans when due. If borrower defaults cause losses in excess of the Company’s allowance for loan losses, it could have an adverse effect on the Company’s business, profitability, and financial condition. Loans secured by real estate, including farmland, multifamily, commercial, one-to-four family residential and construction and development loans, have been a large portion of the Company’s loan portfolio. The Company is subject to risk of future market fluctuations in property values relating to these loans. In addition, multi-family and commercial real estate (“CRE”) loans represent the majority of the Company’s real estate loans outstanding. A decline in tenant occupancy due to such factors or for other reasons could adversely impact the ability of the Company’s borrowers to repay their loans on a timely basis, which could have a negative impact on the Company’s financial condition and results of operation. The Company attempts to manage this risk through rigorous loan underwriting standards. During the ordinary course of business, the Company may foreclose on and take title to properties securing certain loans. In doing so, there is a risk that hazardous or toxic substances could be found on these properties. If hazardous or toxic substances are found, the Company may be liable for remediation costs, as well as for personal injury and property damage. Nonperforming and Restructured Assets The following is a summary of nonperforming and restructured assets: December 31, 2018 2017 (Dollars in thousands) Past due 90 days or more and still accruing $ 1,916 $ 2,893 Nonaccrual 22,603 31,943 Restructured 13,188 4,720 Total nonperforming and restructured loans 37,707 39,556 Other real estate owned and repossessed assets 6,873 4,424 Total nonperforming and restructured assets $ 44,580 $ 43,980 Had nonaccrual loans performed in accordance with their original contractual terms, the Company would have recognized additional interest income of approximately $2.3 million in 2018, $1.8 million in 2017 and $2.0 million in 2016. 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. December 31, 2018 2017 (Dollars in thousands) Real estate: Non-residential real estate owner occupied $ 838 $ 1,108 Non-residential real estate other 187 9,809 Residential real estate permanent mortgage 954 781 Residential real estate all other 5,488 3,980 Commercial and financial: Non-consumer non-real estate 5,682 7,785 Consumer non-real estate 437 250 Other loans 490 5,596 Acquired loans 8,527 2,634 Total $ 22,603 $ 31,943 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 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 As of December 31, 2017 Real estate: Non-residential real estate owner occupied $ 998 $ 68 $ 977 $ 2,043 $ 639,575 $ 641,618 $ 84 Non-residential real estate other 2,905 271 2,112 5,288 1,121,303 1,126,591 432 Residential real estate permanent mortgage 2,211 403 977 3,591 326,743 330,334 584 Residential real estate all other 1,739 749 1,377 3,865 781,790 785,655 973 Commercial and financial: Non-consumer non-real estate 2,210 706 1,785 4,701 1,279,704 1,284,405 403 Consumer non-real estate 2,085 670 293 3,048 285,872 288,920 194 Other loans 506 103 3,916 4,525 139,920 144,445 — Acquired loans 753 192 713 1,658 118,369 120,027 223 Total $ 13,407 $ 3,162 $ 12,150 $ 28,719 $ 4,693,276 $ 4,721,995 $ 2,893 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 year ended December 31, 2018 no material amount of interest income was recognized on impaired loans subsequent to their classification as impaired. During the year ended December 31, 2017, $2.3 million 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 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 As of December 31, 2017 Real estate: Non-residential real estate owner occupied $ 2,011 $ 1,945 $ 141 $ 1,858 Non-residential real estate other 10,323 10,240 496 3,975 Residential real estate permanent mortgage 1,745 1,542 146 1,440 Residential real estate all other 5,837 5,549 2,135 5,258 Commercial and financial: Non-consumer non-real estate 18,101 11,158 2,412 11,131 Consumer non-real estate 545 514 127 541 Other loans 6,092 5,595 178 7,439 Acquired loans 4,737 3,145 12 3,539 Total $ 49,391 $ 39,688 $ 5,647 $ 35,181 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 as follows: Grade 1 – Acceptable - Loans graded 1 represent reasonable and satisfactory credit risk which requires normal attention and supervision. Capacity to repay through primary and/or secondary sources is not questioned. Grade 2 – Acceptable - Increased Attention - This category consists of loans that have credit characteristics deserving management’s close attention. These potential weaknesses could result in deterioration of the repayment prospects for the loan or the Bank’s credit position at some future date. Such credit characteristics include loans to highly leveraged borrowers in cyclical industries, adverse financial trends which could potentially weaken repayment capacity, loans that have fundamental structure deficiencies, loans lacking secondary sources of repayment where prudent, and loans with deficiencies in essential documentation, including financial information. Grade 3 – Loans with Problem Potential - This category consists of performing loans which are considered to exhibit problem potential. Loans in this category would generally include, but not be limited to, borrowers with a weakened financial condition or poor performance history, past dues, loans restructured to reduce payments to an amount that is below market standards and/or loans with severe documentation problems. In general, these loans have no identifiable loss potential in the near future, however; the possibility of a loss developing is heightened. Grade 4 - Problem Loans/Assets – Nonperforming - This category consists of nonperforming loans/assets which are considered to be problems. Nonperforming loans are described as being 90 days and over past due and still accruing, and loans that are nonaccrual. The government guaranteed portion of Small Business Administration (“SBA”) loans is excluded. Grade 5 - Loss Potential - This category consists of loans/assets which are considered to possess loss potential. While the loss may not occur in the current year, management expects that loans/assets in this category will ultimately result in a loss, unless substantial improvement occurs. Grade 6 - Charge Off - This category consists of loans that are considered uncollectible and other assets with little or no value. 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 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 As of December 31, 2017 Real estate: Non-residential real estate owner occupied $ 520,641 $ 105,696 $ 13,852 $ 1,429 $ — $ 641,618 Non-residential real estate other 931,295 178,282 14,290 2,724 — 1,126,591 Residential real estate permanent mortgage 289,200 33,033 6,352 1,749 — 330,334 Residential real estate all other 621,401 149,201 9,418 5,635 — 785,655 Commercial and financial: Non-consumer non-real estate 1,018,172 234,884 24,322 6,997 30 1,284,405 Consumer non-real estate 268,826 17,499 2,038 557 — 288,920 Other loans 136,617 5,668 1,203 957 — 144,445 Acquired loans 65,685 34,418 17,113 2,811 — 120,027 Total $ 3,851,837 $ 758,681 $ 88,588 $ 22,859 $ 30 $ 4,721,995 Allowance for Loan Losses Methodology The allowance for loan losses (“ALL”) is determined by a calculation based on segmenting the loans into the following categories: (1) adversely graded loans [Grades 3, 4 and 5] that have a specific reserve allocation; (2) loans without a specific reserve segmented by loans secured by real estate other than one-to-four family residential property, loans secured by one-to-four family residential property, commercial, industrial and agricultural loans not secured by real estate, consumer purpose loans not secured by real estate, and loans over 60 days past due that are not otherwise Grade 3, 4, or 5; (3) Grade 2 loans; (4) Grade 1 loans and (5) loans held for sale which are excluded. The ALL is calculated as the sum of the following: (1) the total dollar amount of specific reserve allocations; (2) the dollar amount derived by multiplying each segment of adversely graded loans without a specific reserve allocation times its respective reserve factor; (3) the dollar amount derived by multiplying Grade 2 loans and Grade 1 loans (less certain exclusions) times the respective reserve factor; and (4) other adjustments as deemed appropriate and documented by the Senior Loan Committee or Board of Directors. The amount of the ALL is an estimate based upon factors which are subject to rapid change due to changing economic conditions and the economic prospects of borrowers. It is reasonably possible that a material change could occur in the estimated ALL in the near term. 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) As of December 31, 2018 Real estate: Non-residential real estate owner occupied $ 6,195 $ (282 ) $ 17 $ (265 ) $ 398 $ 6,328 Non-residential real estate other 10,519 (93 ) 41 (52 ) 560 11,027 Residential real estate permanent mortgage 3,226 (174 ) 26 (148 ) 183 3,261 Residential real estate all other 9,672 (395 ) 106 (289 ) 1,290 10,673 Commercial and financial: Non-consumer non-real estate 15,334 (2,257 ) 92 (2,165 ) (18 ) 13,151 Consumer non-real estate 2,793 (1,066 ) 245 (821 ) 1,093 3,065 Other loans 2,481 (16 ) 361 345 (403 ) 2,423 Acquired loans 1,446 (720 ) 36 (684 ) 699 1,461 Total $ 51,666 $ (5,003 ) $ 924 $ (4,079 ) $ 3,802 $ 51,389 As of December 31, 2017 Real estate: Non-residential real estate owner occupied $ 5,602 $ (74 ) $ 6 $ (68 ) $ 661 $ 6,195 Non-residential real estate other 10,793 (47 ) 16 (31 ) (243 ) 10,519 Residential real estate permanent mortgage 3,129 (373 ) 25 (348 ) 445 3,226 Residential real estate all other 8,622 (330 ) 66 (264 ) 1,314 9,672 Commercial and financial: Non-consumer non-real estate 12,421 (1,344 ) 1,033 (311 ) 3,224 15,334 Consumer non-real estate 2,804 (913 ) 180 (733 ) 722 2,793 Other loans 4,045 (3,727 ) 23 (3,704 ) 2,140 2,481 Acquired loans 1,277 (157 ) 77 (80 ) 249 1,446 Total $ 48,693 $ (6,965 ) $ 1,426 $ (5,539 ) $ 8,512 $ 51,666 The following table details the amount of ALL by class of loans for the period presented, on the basis of the impairment methodology used by the Company. ALL December 31, 2018 December 31, 2017 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 $ 669 $ 5,659 $ 656 $ 5,539 Non-residential real estate other 1,119 9,908 751 9,768 Residential real estate permanent mortgage 505 2,756 483 2,743 Residential real estate all other 3,413 7,260 2,761 6,911 Commercial and financial: Non-consumer non-real estate 2,114 11,037 4,651 10,683 Consumer non-real estate 374 2,691 429 2,364 Other loans 65 2,358 133 2,348 Acquired loans — 1,461 12 1,434 Total $ 8,259 $ 43,130 $ 9,876 $ 41,790 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 December 31, 2018 December 31, 2017 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 $ 17,846 $ 608,775 $ — $ 15,281 $ 626,337 $ — Non-residential real estate other 25,333 1,120,795 — 17,013 1,109,578 — Residential real estate permanent mortgage 9,026 319,676 — 8,100 322,234 — Residential real estate all other 21,285 806,219 — 15,052 770,603 — Commercial and financial: Non-consumer non-real estate 19,432 1,264,222 — 31,349 1,253,056 — Consumer non-real estate 3,093 323,769 — 2,600 286,320 — Other loans 209 141,700 — 764 143,681 — Acquired loans 22,132 265,084 7,380 14,464 100,106 5,457 Total $ 118,356 $ 4,850,240 $ 7,380 $ 104,623 $ 4,611,915 $ 5,457 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: Year ended December 31, 2018 2017 2016 (Dollars in thousands) Other real estate owned $ 5,437 $ 2,889 $ 2,553 Repossessed assets 1,122 1,242 1,402 Total $ 6,559 $ 4,131 $ 3,955 Related Party Loans The Company has made loans in the ordinary course of business to the executive officers and directors of the Company and to certain affiliates of these executive officers and directors. Management believes that all such loans were made on substantially the same terms as those prevailing at the time for comparable transactions with other persons and do not represent more than a normal risk of collectability or present other unfavorable features. A summary of these loans is as follows: Year Ended December 31, Balance Beginning of the Period Additions Collections/ Terminations Balance End of the Period (Dollars in thousands) 2018 $ 24,001 $ 7,986 $ (12,096 ) $ 19,891 2017 27,486 7,350 (10,835 ) 24,001 2016 37,577 16,133 (26,224 ) 27,486

Premises and Equipment, Net and

Premises and Equipment, Net and Other Assets	12 Months Ended
	Dec. 31, 2018
Property Plant And Equipment [Abstract]
Premises and Equipment, Net and Other Assets	(6) PREMISES AND EQUIPMENT, NET AND OTHER ASSETS The following is a summary of premises and equipment by classification: December 31, Estimated Useful Lives 2018 2017 (Dollars in thousands) Land $ 35,434 $ 34,833 Buildings 10 to 40 years 181,182 145,051 Furniture, fixtures and equipment 3 to 15 years 75,138 69,915 Accumulated depreciation (117,392 ) (115,711 ) Premises and equipment, net $ 174,362 $ 134,088 Low Income Housing Tax Credit Investments We invest in affordable housing projects that qualify for the low income housing tax credit (LIHTC), which is designed to promote private development of low income housing. These investments generate a return primarily through realization of federal tax credits, and also through a tax deduction generated by operating losses of the investments. The investments are amortized through tax expense using the proportional amortization method as related tax credits are utilized. The Company is periodically required to provide additional contributions at the discretion of the project sponsors. Although in some cases the Company’s investment may exceed 50% of the equity interest in an entity, the Company does not consolidate these structures as variable interest entities due to the project sponsor’s ability to manage the projects, which is indicative of power in them. Total LIHTC investments were $18.5 million and $16.9 million at December 31, 2018 and 2017, respectively and are included in other assets on the balance sheet. The Company recognized tax credits and other tax benefits of $5.4 million, $4.4 million and $4.2 million in 2018, 2017 and 2016, respectively and amortization expense of $4.4 million, $3.5 million and $2.9 million in 2018, 2017 and 2016, respectively resulting from LIHTC investments. Additional contributions are committed during the investment periods through the year 2032. Unfunded commitments to these investments as of December 31, 2018 totaled $17.3 million.

Intangible Assets and Goodwill

Intangible Assets and Goodwill	12 Months Ended
	Dec. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Intangible Assets and Goodwill	(7) INTANGIBLE ASSETS AND GOODWILL The following is a summary of intangible assets: Gross Carrying Amount Accumulated Amortization Net Carrying Amount (Dollars in thousands) 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 As of December 31, 2017 Core deposit intangibles $ 17,447 $ (8,451 ) $ 8,996 Customer relationship intangibles 5,699 (3,767 ) 1,932 Mortgage servicing intangibles 439 (285 ) 154 Total $ 23,585 $ (12,503 ) $ 11,082 Mortgage servicing intangibles are amortized based on current prepayment assumptions and are adjusted to fair value periodically, if impaired. Fair value is estimated based on the present value of future cash flows over several interest rate scenarios, which are then discounted at risk-adjusted rates. The Company considers portfolio characteristics, contractually specified servicing fees, prepayment assumptions, delinquency rates, late charges, other ancillary revenue, costs to service and other economic factors. When available, fair value estimates and assumptions are compared to observable market data and the recent market activity and actual portfolio experience. Estimated amortization of intangible assets for the next five years, as of December 31, 2018, is as follows (dollars in thousands): Estimated Amortization 2019 $ 3,056 2020 2,975 2021 2,246 2022 1,935 2023 1,811 At December 31, 2018, the weighted-average remaining life of all intangible assets was approximately 6.7 years which consisted of customer relationship intangibles with a weighted-average life of 5.1 years, core deposit intangibles with a weighted-average life of 6.9 years and mortgage servicing intangibles with a weighted-average life of 2.0 years based on current prepayment assumptions. The following is a summary of goodwill by business segment: Other Executive, Metropolitan Community Financial Operations Banks Banks Services & Support Consolidated (Dollars in thousands) Year Ended December 31, 2018 Balance at beginning of period $ 8,078 $ 39,876 $ 5,464 $ 624 $ 54,042 Acquisitions 5,689 20,018 — — 25,707 Balance at end of period $ 13,767 $ 59,894 $ 5,464 $ 624 $ 79,749 Year Ended December 31, 2017 Balance at beginning and end of period $ 8,078 $ 39,876 $ 5,464 $ 624 $ 54,042

Time Deposits

Time Deposits	12 Months Ended
	Dec. 31, 2018
Deposits [Abstract]
Time Deposits	(8) TIME DEPOSITS Time deposits include certificates of deposit and individual retirement accounts. At December 31, 2018, the scheduled maturities of all time deposits are as follows (Dollars in thousands): 2019 $ 458,378 2020 122,648 2021 53,661 2022 39,979 2023 31,276 Thereafter 4 Total $ 705,946 The following table is a summary of large time deposits and time deposits that meet or exceed the current FDIC insurance limit for the periods presented: December 31, 2018 2017 (Dollars in thousands) Time deposits of $100,000 or more $ 349,918 $ 319,811 Time deposits of $250,000 or more 132,957 122,391

Short-Term Borrowings

Short-Term Borrowings	12 Months Ended
	Dec. 31, 2018
Short Term Borrowings [Abstract]
Short-Term Borrowings	(9) SHORT-TERM BORROWINGS The following is a summary of short-term borrowings: December 31, 2018 2017 (Dollars in thousands) Federal funds purchased $ 1,675 $ 900 Weighted average interest rate 1.84 % 0.97 % End of period interest rate 2.30 % 1.38 % Federal funds purchased represent borrowings of overnight funds from other financial institutions.

Long-Term Borrowings

Long-Term Borrowings	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Long-Term Borrowings	(10) LONG-TERM BORROWINGS The Company has a line of credit from the Federal Home Loan Bank (“FHLB”) of Topeka, Kansas to use for liquidity or to match-fund certain long-term fixed rate loans. The Company’s assets, including residential first mortgages of $775.3 million, are pledged as collateral for the borrowings under the line of credit. As of December 31, 2018, the Company had the ability to draw up to $619.1 million on the FHLB line of credit based on FHLB stock holdings of $553,400 with no advances outstanding. In addition, the Company has a revolving line of credit with another financial institution with the ability to draw up to $10.0 million with no advances outstanding. This line of credit has a variable rate based on prime rate minus 25 basis points and matures in 2020.

Junior Subordinated Debentures

Junior Subordinated Debentures	12 Months Ended
	Dec. 31, 2018
Offsetting [Abstract]
Junior Subordinated Debentures	(11) JUNIOR SUBORDINATED DEBENTURES In January 2004, the Company established BFC Capital Trust II (“BFC II”), a trust formed under the Delaware Business Trust Act. The Company owns all of the common securities of BFC II. In February 2004, BFC II issued $25 million of aggregate liquidation amount of 7.20% Cumulative Trust Preferred Securities (the “Cumulative Trust Preferred Securities”) to other investors. In March 2004, BFC II issued an additional $1 million in Cumulative Trust Preferred Securities through the execution of an over-allotment option. The proceeds from the sale of the Cumulative Trust Preferred Securities and the common securities of BFC II were invested in $26.8 million of 7.20% Junior Subordinated Debentures of the Company. Interest payments on the $26.8 million of 7.20% Junior Subordinated Debentures are payable January 15, April 15, July 15 and October 15 of each year. Such interest payments may be deferred for up to twenty consecutive quarters. The stated maturity date of the $26.8 million of 7.20% Junior Subordinated Debentures is March 31, 2034, but they are subject to mandatory redemption pursuant to optional prepayment terms. The Cumulative Trust Preferred Securities represent an undivided interest in the $26.8 million of 7.20% Junior Subordinated Debentures and are guaranteed by the Company. During any deferral period or during any event of default, the Company may not declare or pay any dividends on any of its capital stock. The Cumulative Trust Preferred Securities were callable at par, in whole or in part, after March 31, 2009. On October 8, 2015, the Company acquired CSB Bancshares Statutory Trust I (CSB Trust I), a trust formed under the Delaware Business Trust Act, from the merger of CSB Bancshares Inc. CSB Trust I had issued $5.0 million aggregate liquidation amount of floating rate capital securities to other purchasers and $155,000 aggregate liquidation amount of common securities to CSB Bancshares Inc., which were assumed by the Company as a result of the merger. The proceeds from the sale of the securities of CSB Trust I were invested in $5.2 million of Floating Rate Junior Subordinated Deferrable Interest Debentures of CSB Bancshares Inc., which were assumed by the Company as a result of the merger. Interest payments on the $5.2 million of Floating Rate Junior Subordinated Deferrable Interest Debentures were payable March 15, June 15, September 15 and December 15 of each year. The interest rate on the $5.2 million of Floating Rate Junior Subordinated Deferrable Interest Debentures was set at three month LIBOR plus 182 basis points. The Floating Rate Junior Subordinated Deferrable Interest Debentures was due September 15, 2036. On December 17, 2018 the Company redeemed the Floating Rate Junior Subordinated Deferrable Interest Debentures and subsequently dissolved CSB Trust I.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	(12) INCOME TAXES The components of the Company’s income tax expense (benefit) are as follows: Year Ended December 31, 2018 2017 2016 (Dollars in thousands) Current taxes: Federal $ 23,700 $ 39,569 $ 34,003 State 7,083 5,914 5,308 Deferred taxes 3,155 4,383 (2,048 ) Total income taxes $ 33,938 $ 49,866 $ 37,263 Income tax expense (benefit) applicable to securities transactions approximated $10,000, $1.4 million and $(21,000) for the years ended December 31, 2018, 2017 and 2016, respectively. Income tax expense for 2017 was impacted by the write-down of net deferred tax asset of $4.3 million resulting from the federal tax rate change under the Tax Cuts and Jobs Act, enacted December 22, 2017. A reconciliation of tax expense at the federal statutory tax rate applied to income before taxes is presented in the following table. The federal statutory tax rate was 21% in 2018 and 35% in 2017 and 2016: Year Ended December 31, 2018 2017 2016 (Dollars in thousands) Tax expense at the federal statutory tax rate $ 33,546 $ 47,708 $ 37,778 Increase (decrease) in tax expense from: Tax-exempt income, net (510 ) (829 ) (756 ) Modified endowment life contracts (558 ) (921 ) (852 ) Share based compensation excess tax benefit (917 ) (2,354 ) — State tax expense, net of federal tax benefit 5,595 3,840 3,250 Write-down of net deferred tax asset — 4,331 — Utilization of tax credits: New markets tax credits (1,422 ) (1,151 ) (1,254 ) Low-income housing tax credits, net of amortization (1,273 ) (1,589 ) (1,424 ) Other tax credits — — (319 ) Other, net (523 ) 831 840 Total tax expense $ 33,938 $ 49,866 $ 37,263 The net deferred tax asset consisted of the following and is reported in other assets: December 31, 2018 2017 (Dollars in thousands) Provision for loan losses $ 13,089 $ 13,123 Unrealized net losses on securities 731 739 Write-downs of other real estate owned 462 473 Deferred compensation 2,209 2,113 Stock-based compensation 1,448 1,351 Investments in partnership interests 4,274 3,758 Other 963 275 Gross deferred tax assets 23,176 21,832 Premium on securities of banks acquired (185 ) (219 ) Intangibles (5,376 ) (3,359 ) Basis difference related to tax credits (2,560 ) (2,713 ) Depreciation (8,484 ) (4,563 ) Leveraged lease — (821 ) Prepaid expense deducted (1,178 ) (887 ) Other (181 ) (180 ) Gross deferred tax liabilities (17,964 ) (12,742 ) Net deferred tax asset $ 5,212 $ 9,090 The Company recognizes accrued interest and penalties related to unrecognized tax benefits, if applicable, in income tax expense. During the years ended December 31, 2018, 2017 and 2016, the Company did not recognize or accrue any interest and penalties related to unrecognized tax benefits. Federal and various state income tax statutes dictate that tax returns filed in any of the previous three reporting periods remain open to examination, which includes the years 2016 to 2018. In addition, years 2013 to 2015 remain open due to amending returns in 2017. The Company has no open examinations with either the Internal Revenue Service or any state agency. Management performs an analysis of the Company’s tax position annually and believes it is more likely than not that all of its tax positions will be utilized in future years.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	(13) 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 December 31, 2018, there were 282,970 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 December 31, 2018 will become exercisable through the year 2025. 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 December 31, 2018, 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 December 31, 2018 will become exercisable through the year 2022. 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) Year Ended December 31, 2018 Outstanding at December 31, 2017 1,273,625 $ 25.90 Options granted 72,000 56.47 Options exercised (123,925 ) 17.42 Options canceled, forfeited, or expired (5,000 ) 48.02 Outstanding at December 31, 2018 1,216,700 28.48 9.53Yrs $ 26,066 Exercisable at December 31, 2018 601,700 21.53 7.12Yrs $ 17,070 Year Ended December 31, 2017 Outstanding at December 31, 2016 1,414,900 $ 22.46 Options granted 121,500 48.26 Options exercised (262,775 ) 17.73 Outstanding at December 31, 2017 1,273,625 25.90 9.73Yrs $ 32,165 Exercisable at December 31, 2017 566,625 20.07 6.92Yrs $ 17,611 The following table has additional information regarding options exercised under both the BancFirst ISOP and the BancFirst Directors’ Stock Option Plan: Year Ended December 31, 2018 2017 2016 (Dollars in thousands) Total intrinsic value of options exercised $ 4,810 $ 8,389 $ 12,230 Cash received from options exercised 2,159 4,660 9,720 Tax benefit realized from options exercised 1,225 3,245 4,731 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: Year Ended December 31, 2018 2017 206 (Dollars in thousands) Stock-based compensation expense $ 1,352 $ 1,180 $ 1,636 Tax benefit 345 301 633 Stock-based compensation expense, net of tax $ 1,007 $ 879 $ 1,003 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: December 31, 2018 (Dollars in thousands) Unearned stock-based compensation expense $ 3,319 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: Year Ended December 31, 2018 2017 2016 Weighted average grant-date fair value per share of options granted $ 14.71 $ 11.87 $ 5.96 Risk-free interest rate 2.55 to 3.05% 2.15 to 2.40% 1.46 to 2.02% Dividend yield 2.00 % 2.00 % 2.00 % Stock price volatility 23.05 to 23.95% 22.57 to 24.18% 20.41 to 21.78% Expected term 10 Yrs 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 3,891 and 9,918 shares of common stock distributed from the BancFirst Deferred Stock Compensation Plan during the years ended December 31, 2018 and 2017, respectively. A summary of the accumulated stock units is as follows: December 31, 2018 2017 Accumulated stock units 143,347 138,768 Average price $ 24.91 $ 22.84

Retirement Plans

Retirement Plans	12 Months Ended
	Dec. 31, 2018
Compensation And Retirement Disclosure [Abstract]
Retirement Plans	(14) RETIREMENT PLANS In May 1986, the Company adopted the BancFirst Corporation Employee Stock Ownership (“ESOP”) and Thrift Plan (“401(k)”) effective January 1, 1985. The plan was separated into two individual plans effective January 1, 2009. The 401(k) and ESOP plans cover all eligible employees, as defined in the plans, of the Company and its subsidiaries. The 401(k) plan allows employees to defer up to the maximum legal limit of their compensation, of which the Company may match up to 3% of their compensation. In addition, the Company may make discretionary contributions based on employee contributions or eligible compensation to the ESOP plan, as determined by the Company’s Board of Directors. The aggregate amounts of contributions by the Company to the 401(k) and ESOP plans are shown in the following table: December 31, 2018 2017 2016 (Dollars in thousands) 401(k) contributions $ 2,465 $ 2,229 $ 2,074 ESOP contributions 4,073 2,645 2,352 Total contributions $ 6,538 $ 4,874 $ 4,426

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Stockholders' Equity	(15) STOCKHOLDERS’ EQUITY As of December 31, 2018, 2017 and 2016 the Company’s authorized and outstanding preferred and common stock was as follows: No. of Shares Authorized at No. of Shares Outstanding at December 31, Class of Stock December 31, 2018 2018 2017 2016 Par Value Per Share Dividends Voting Rights Senior Preferred 10,000,000 — — — $ 1.00 As declared Voting 10% Cumulative Preferred 900,000 — — — 5.00 As declared Non-voting Common 40,000,000 32,603,926 31,894,563 31,621,870 1.00 As declared Voting The following is a description of the capital stock of the Company: (a) Senior Preferred Stock: No shares issued or outstanding. Shares may be issued with such voting, dividend, redemption, sinking fund, conversion, exchange, liquidation and other rights as shall be determined by the Company’s Board of Directors, without approval of the stockholders. The Senior Preferred Stock would have a preference over common stock as to payment of dividends, as to the right to distribution of assets upon redemption of such shares or upon liquidation of the Company. (b) 10% Cumulative Preferred Stock: Redeemable at the Company’s option at $5.00 per share plus accumulated dividends; non-voting; cumulative dividends at the rate of 10% payable semi-annually on January 15 and July 15; no shares issued or outstanding. (c) Common stock: At December 31, 2018, 2017 and 2016 the shares issued equaled shares outstanding. 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 may be determined by management within the limitations of the SRP. The following table is a summary of the shares under the program: Year Ended December 31, 2018 2017 2016 Number of shares repurchased 151,264 — 200,000 Average price of shares repurchased $ 52.32 $ — $ 27.62 Shares remaining to be repurchased 148,736 300,000 300,000 The Company’s ability to pay dividends is dependent upon dividend payments received from BancFirst. Banking regulations limit bank dividends based upon net earnings retained and minimum capital requirements. Dividends in excess of these requirements require regulatory approval. At January 1, 2019, approximately $140.3 million of the equity of BancFirst was available for dividend payments to the Company. During any deferral period or any event of default on the Junior Subordinated Debentures, the Company may not declare or pay any dividends on any of its capital stock. 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 December 31, 2018, 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 December 31, 2018: Total Capital (to Risk Weighted Assets)- BancFirst Corporation $ 886,190 16.29 % $ 435,208 8.00% $ 537,210 9.875 % N/A N/A BancFirst 765,487 14.09 % 434,573 8.00% 536,426 9.875 % $ 543,216 10.00 % Common Equity Tier 1 Capital (to Risk Weighted Assets)- BancFirst Corporation $ 808,801 14.87 % $ 244,804 4.50% $ 346,806 6.375 % N/A N/A BancFirst 694,098 12.78 % 244,447 4.50% 346,300 6.375 % $ 353,090 6.50 % Tier 1 Capital (to Risk Weighted Assets)- BancFirst Corporation $ 834,801 15.35 % $ 326,406 6.00% $ 428,408 7.875 % N/A N/A BancFirst 714,098 13.15 % 325,930 6.00% 427,783 7.875 % $ 434,573 8.00 % Tier 1 Capital (to Total Assets)- BancFirst Corporation $ 834,801 11.09 % $ 301,116 4.00% N/A N/A N/A N/A BancFirst 714,098 9.49 % 300,855 4.00% N/A N/A $ 376,069 5.00 % As of December 31, 2017: Total Capital (to Risk Weighted Assets)- BancFirst Corporation $ 797,015 15.62 % $ 408,234 8.00% $ 472,020 9.250 % N/A N/A BancFirst 714,964 14.03 % 407,698 8.00% 471,401 9.250 % $ 509,622 10.00 % Common Equity Tier 1 Capital (to Risk Weighted Assets)- BancFirst Corporation $ 714,349 14.00 % $ 229,632 4.50% $ 293,418 5.750 % N/A N/A BancFirst 643,298 12.62 % 229,330 4.50% 293,033 5.750 % $ 331,255 6.50 % Tier 1 Capital (to Risk Weighted Assets)- BancFirst Corporation $ 745,349 14.61 % $ 306,175 6.00% $ 369,962 7.250 % N/A N/A BancFirst 663,298 13.02 % 306,773 6.00% 369,476 7.250 % $ 407,698 8.00 % Tier 1 Capital (to Total Assets)- BancFirst Corporation $ 745,349 10.44 % $ 285,444 4.00% N/A N/A N/A N/A BancFirst 663,298 9.31 % 285,101 4.00% N/A N/A $ 356,677 5.00 % As of December 31, 2018, the most recent notification from the Federal Reserve Bank of Kansas City and the FDIC categorized BancFirst as “well capitalized” under the regulatory framework for 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 notification 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 will be phased in over a four-year period (increasing by that amount on each subsequent January 1, until it reaches 2.5% on January 1, 2019). Management believes that, as of December 31, 2018, the Company and BancFirst would meet all capital adequacy requirements under the Basel III Capital Rules on a fully phased-in basis as if such requirements were currently in effect.

Net Income Per Common Share

Net Income Per Common Share	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Net Income Per Common Share	(16) NET INCOME PER COMMON SHARE Basic and diluted net income per common share are calculated as follows: Income (Numerator) Shares (Denominator) Per Share Amount (Dollars in thousands, except per share data) Year Ended December 31, 2018 Basic Income available to common stockholders $ 125,814 32,689,228 $ 3.85 Effect of stock options — 741,486 Diluted Income available to common stockholders plus assumed exercises of stock options $ 125,814 33,430,714 $ 3.76 Year Ended December 31, 2017 Basic Income available to common stockholders $ 86,439 31,813,572 $ 2.72 Effect of stock options — 754,533 Diluted Income available to common stockholders plus assumed exercises of stock options $ 86,439 32,568,105 $ 2.65 Year Ended December 31, 2016 Basic Income available to common stockholders $ 70,674 31,230,340 $ 2.27 Effect of stock options — 592,184 Diluted Income available to common stockholders plus assumed exercises of stock options $ 70,674 31,822,524 $ 2.22 The following table shows the number and average exercise price of options that were excluded from the computation of diluted net income per common share for each year because the options were anti-dilutive for the period. Shares Average Exercise December 31, 2018 92,738 $ 53.17 December 31, 2017 55,337 46.86 December 31, 2016 294,438 30.25

Condensed Parent Company Financ

Condensed Parent Company Financial Statements	12 Months Ended
	Dec. 31, 2018
Condensed Financial Information Of Parent Company Only Disclosure [Abstract]
Condensed Parent Company Financial Statements	(17) CONDENSED PARENT COMPANY FINANCIAL STATEMENTS BALANCE SHEETS December 31, 2018 2017 (Dollars in thousands) ASSETS Cash $ 105,089 $ 67,917 Investments in subsidiaries 822,336 737,031 Goodwill 624 624 Dividends receivable 11,058 7,788 Other assets 958 1,401 Total assets $ 940,065 $ 814,761 LIABILITIES AND STOCKHOLDERS’ EQUITY Other liabilities $ 10,472 $ 7,173 Junior subordinated debentures 26,804 31,959 Stockholders’ equity 902,789 775,629 Total liabilities and stockholders’ equity $ 940,065 $ 814,761 STATEMENTS OF INCOME Year Ended December 31, 2018 2017 2016 (Dollars in thousands) OPERATING INCOME Dividends from subsidiaries $ 38,326 $ 29,455 $ 28,175 Interest on interest-bearing deposits 1,151 291 160 Other 16 3 3 Total operating income 39,493 29,749 28,338 OPERATING EXPENSE Interest 2,172 2,122 2,096 Other 698 770 583 Total operating expense 2,870 2,892 2,679 Income before taxes and equity in undistributed earnings of subsidiaries 36,623 26,857 25,659 Allocated income tax benefit 3,093 3,295 1,244 Income before equity in undistributed earnings of subsidiaries 39,716 30,152 26,903 Equity in undistributed earnings of subsidiaries 87,404 57,429 44,172 Amortization of stock-based compensation arrangements of subsidiaries (1,306 ) (1,142 ) (401 ) Net income $ 125,814 $ 86,439 $ 70,674 STATEMENTS OF CASH FLOW Year Ended December 31, 2018 2017 2016 (Dollars in thousands) CASH FLOWS FROM OPERATING ACTIVITIES Net income $ 125,814 $ 86,439 $ 70,674 Adjustments to reconcile to net cash provided by operating activities: Equity in undistributed earnings of subsidiaries (87,404 ) (57,429 ) (44,172 ) Amortization of stock-based compensation arrangements of subsidiaries 1,306 1,142 401 Other, net (2,621 ) 569 136 Net cash provided by operating activities 37,095 30,721 27,039 INVESTING ACTIVITIES Net cash provided by acquisitions 41,347 — — Payments for investments in subsidiaries — (502 ) — Other, net (174 ) 100 — Net cash provided by (used in) investing activities 41,173 (402 ) — FINANCING ACTIVITIES Issuance of common stock 2,238 4,844 13,354 Common stock acquired (7,914 ) — (5,523 ) Cash dividends paid (30,265 ) (24,783 ) (22,770 ) Redemption of Junior Subordinated debentures (5,155 ) — — Net cash used for financing activities (41,096 ) (19,939 ) (14,939 ) Net increase in cash 37,172 10,380 12,100 Cash and due from banks at the beginning of the period 67,917 57,537 45,437 Cash and due from banks at the end of the period $ 105,089 $ 67,917 $ 57,537 SUPPLEMENTAL DISCLOSURE Cash paid during the period for interest $ 2,171 $ 2,122 $ 2,096 Cash received during the period for income taxes, net $ 3,647 $ 4,643 $ 5,031

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2018
Related Party Transactions [Abstract]
Related Party Transactions	(18) RELATED PARTY TRANSACTIONS Refer to Note (5) for information regarding loan transactions with related parties.

Commitments and Contingent Liab

Commitments and Contingent Liabilities	12 Months Ended
	Dec. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingent Liabilities	(19) COMMITMENTS AND CONTINGENT LIABILITIES The Company is a party to financial instruments with off balance sheet risk in the normal course of business to meet the financing needs of its customers. These financial instruments include loan commitments and standby letters of credit which involve elements of credit and interest-rate risk to varying degrees. The Company’s exposure to credit loss in the event of nonperformance by the other party to the instrument is represented by the instrument’s contractual amount. To control this credit risk, the Company uses the same underwriting standards as it uses for loans recorded on the balance sheet. The amounts of financial instruments with off-balance-sheet risk are as follows: December 31, 2018 2017 (Dollars in thousands) Loan commitments $ 1,232,996 $ 1,050,686 Stand-by letters of credit 56,096 57,074 Loan commitments are agreements to lend to a customer, as long as there is no violation of any condition established in the contract. Stand-by letters of credit are conditional commitments issued by the Company to guarantee the performance of a customer to a third party. These instruments generally have fixed expiration dates or other termination clauses and may require payment of a fee. Since many of the instruments are expected to expire without being drawn upon, the total amounts do not necessarily represent commitments that will be funded in the future. 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. Future minimum lease payments required under operating leases that have an initial or remaining non-cancelable lease term in excess of one year at December 31, 2018, were as follows (Dollars in thousands): 2019 $ 1,049 2020 789 2021 569 2022 369 2023 60 Later years 499 Total $ 3,335 Rental expense on all operating leases, including those rented on a monthly or temporary basis were as follows (Dollars in thousands): Year Ending December 31: 2018 $ 1,857 2017 1,597 2016 1,524 The Company is a defendant in legal actions arising from normal business activities. Management believes that all legal actions against the Company are without merit or that the ultimate liability, if any, resulting from them will not materially affect the Company’s financial statements.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	(20) 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 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. Equity Securities 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. For periods prior to January 1, 2018, equity securities were classified as available-for-sale and stated at fair value with unrealized gains and losses reported as a separate component of accumulated other comprehensive income (loss), net of tax. 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 December 31, 2018 and 2017, 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) 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 Equity securities — — 7,521 7,521 Derivative assets — 252 — 252 Derivative liabilities — 238 — 238 December 31, 2017 Securities available for sale: U.S. Treasury $ 312,802 $ — $ — $ 312,802 U.S. federal agencies — 88,851 — 88,851 Mortgage-backed securities — 3,509 14,467 17,976 States and political subdivisions — 42,370 — 42,370 Equity securities — — 5,704 5,704 Derivative assets — 295 — 295 Derivative liabilities — 261 — 261 The changes in Level 3 assets measured at estimated fair value on a recurring basis during the years ended December 31, 2018 and 2017 were as follows: Twelve Months Ended December 31, 2018 2017 (Dollars in thousands) Balance at the beginning of the year $ 20,171 $ 21,385 Purchases 3,190 1,668 Settlements (2,446 ) (722 ) Sales (75 ) (5,412 ) Gains included in earnings 118 4,060 Total unrealized gains/(losses) 6 (808 ) Balance at the end of the period $ 20,964 $ 20,171 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 years ended December 31, 2018 and 2017, the Company did not transfer any securities between levels in the fair value hierarchy. Financial Assets and Financial Liabilities Measured at Fair Value on a Nonrecurring Basis Certain financial assets and financial liabilities are measured at fair value on a nonrecurring basis; that is, the instruments are not measured at fair value on an ongoing basis but are subject to fair value adjustments in certain circumstances (for example, when there is evidence of impairment). These financial assets and financial liabilities are reported at fair value utilizing Level 3 inputs. Impaired loans are reported at the fair value of the underlying collateral if repayment is dependent on liquidation of the collateral. In no case does the fair value of an impaired loan exceed the fair value of the underlying collateral. The impaired loans are adjusted to fair value through a specific allocation of the allowance for loan losses or a direct charge-down of the loan. 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 December 31, 2018 Impaired loans (less specific allowance) $ 34,396 Repossessed assets 183 Other real estate owned 4,683 As of and for the Year-to-date Period Ended December 31, 2017 Impaired loans (less specific allowance) $ 34,041 Repossessed assets 288 Other real estate owned 1,995 Estimated Fair Value of Financial Instruments The Company is required under current authoritative accounting guidance to disclose the estimated fair value of their financial instruments that are not recorded at fair value. For the Company, as for most financial institutions, substantially all of its assets and liabilities are considered financial instruments. A financial instrument is defined as cash, evidence of an ownership interest in an entity or a contract that creates a contractual obligation or right to deliver or receive cash or another financial instrument from a second entity. The following methods and assumptions were used to estimate the fair value of each class of financial instruments: Cash and Cash Equivalents Include: Cash and Due from Banks, Federal Funds Sold and Interest-Bearing Deposits The carrying amount of these short-term instruments is a reasonable estimate of fair value. Securities Held for Investment For securities held for investment, which are generally traded in secondary markets, fair values are based on quoted market prices or dealer quotes, if available. If a quoted market price is not available, fair value is estimated using quoted market prices for similar securities making adjustments for credit or liquidity if applicable. Loans 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 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: December 31, 2018 2017 Carrying Amount Fair Value Carrying Amount Fair Value (Dollars in thousands) FINANCIAL ASSETS Level 2 inputs: Cash and cash equivalents $ 1,424,255 $ 1,424,255 $ 1,758,575 $ 1,758,575 Securities held for investment 928 933 1,792 1,803 Loans held for sale 8,174 8,174 6,173 6,173 Level 3 inputs: Securities held for investment 500 500 500 500 Loans, net of allowance for loan losses 4,924,587 4,901,159 4,670,329 4,663,608 FINANCIAL LIABILITIES Level 2 inputs: Deposits 6,605,495 6,713,542 6,415,045 6,490,309 Short-term borrowings 1,675 1,675 900 900 Junior subordinated debentures 26,804 29,549 31,959 34,661 OFF-BALANCE SHEET FINANCIAL INSTRUMENTS Loan commitments 2,158 1,839 Letters of credit 421 428 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 servicing 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, of which there were none as of December 31, 2018 or 2017. 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 December 31, 2018 or 2017.

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Segment Information	(21) 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) December 31, 2018 Net interest income $ 84,043 $ 170,096 $ 5,341 $ 996 $ — $ 260,476 Provision for loan losses 79 4,178 (466 ) 11 — 3,802 Noninterest income 16,625 60,004 37,743 137,364 (126,537 ) 125,199 Depreciation and amortization 2,364 9,092 588 1,502 — 13,546 Other expenses 36,873 106,674 24,895 42,319 (2,186 ) 208,575 Income before taxes $ 61,352 $ 110,156 $ 18,067 $ 94,528 $ (124,351 ) $ 159,752 Total assets $ 2,743,876 $ 4,892,946 $ 84,706 $ 861,782 $ (1,009,052 ) $ 7,574,258 Capital expenditures $ 3,003 $ 21,393 $ 1,035 $ 26,432 $ — $ 51,863 December 31, 2017 Net interest income (expense) $ 74,274 $ 147,731 $ 5,770 $ (636 ) $ — $ 227,139 Provision for loan losses 2,457 4,442 1,767 (154 ) — 8,512 Noninterest income 15,698 54,353 37,842 97,368 (87,191 ) 118,070 Depreciation and amortization 2,192 7,790 584 1,225 — 11,791 Other expenses 35,488 93,619 24,474 36,531 (1,511 ) 188,601 Income before taxes $ 49,835 $ 96,233 $ 16,787 $ 59,130 $ (85,680 ) $ 136,305 Total assets $ 2,552,024 $ 4,544,196 $ 117,332 $ 885,590 $ (845,986 ) $ 7,253,156 Capital expenditures $ 3,606 $ 12,334 $ 64 $ 2,003 $ — $ 18,007 December 31, 2016 Net interest income (expense) $ 63,519 $ 135,508 $ 6,132 $ (1,331 ) $ — $ 203,828 Provision for loan losses 2,229 7,509 1,653 128 — 11,519 Noninterest income 16,372 57,745 29,711 75,415 (72,211 ) 107,032 Depreciation and amortization 2,341 8,281 510 1,251 — 12,383 Other expenses 34,130 96,627 22,216 26,375 (327 ) 179,021 Income before taxes $ 41,191 $ 80,836 $ 11,464 $ 46,330 $ (71,884 ) $ 107,937 Total assets $ 2,493,096 $ 4,412,174 $ 83,594 $ 803,810 $ (773,722 ) $ 7,018,952 Capital expenditures $ 1,525 $ 7,738 $ 125 $ 1,447 $ — $ 10,835 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.

Selected Quarterly Financial Da

Selected Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial Data (Unaudited)	(22) SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) A summary of the unaudited quarterly results of operations for the years ended December 31, 2018 and 2017 is as follows: Quarter Fourth Third Second First (Dollars in thousands, except per share data) 2018 Net interest income $ 66,888 $ 65,673 $ 64,880 $ 63,035 Provision for loan losses 1,516 747 1,225 314 Securities transactions 10 (64 ) 115 (14 ) Noninterest income 31,851 32,801 30,437 30,110 Noninterest expense 56,166 55,809 54,256 55,890 Net income 32,725 32,883 30,586 29,620 Net income per common share: Basic 1.00 1.01 0.93 0.91 Diluted 0.98 0.98 0.91 0.89 2017 Net interest income $ 58,699 $ 57,233 $ 56,439 $ 54,768 Provision for loan losses 3,323 3,276 1,841 72 Securities transactions 4,412 (22 ) (330 ) — Noninterest income 32,833 29,169 27,983 28,085 Noninterest expense 51,251 50,600 48,953 49,588 Net income 19,497 21,710 23,182 22,050 Net income per common share: Basic 0.61 0.68 0.73 0.70 Diluted 0.59 0.67 0.71 0.68

Description of Business and S_2

Description of Business and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Nature of Operations	Nature of Operations BancFirst Corporation is an Oklahoma business corporation and a financial holding company under federal law. It conducts virtually all of its operating activities through its principal wholly-owned subsidiary, BancFirst (the “Bank” or “BancFirst”), a state-chartered bank headquartered in Oklahoma City, Oklahoma. The Bank provides a wide range of retail and commercial banking services, including: commercial, real estate, agricultural and consumer lending; depository and funds transfer services; collections; safe deposit boxes; cash management services; retail brokerage services; and other services tailored for both individual and corporate customers. The Bank also offers trust services and acts as executor, administrator, trustee, transfer agent and in various other fiduciary capacities. Through its Technology and Operations Center, the Bank provides item processing, research and other correspondent banking services to financial institutions and governmental units. The Company’s wholly-owned subsidiary, BancFirst Insurance Services, Inc., an independent insurance agency, offers a variety of commercial and personal insurance products. In addition, the Company’s wholly-owned subsidiary, Council Oak Partners, LLC, an Oklahoma limited liability company, engages in investing activities.
Basis of Presentation	Basis of Presentation The accompanying 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 consolidated financial statements. Certain amounts from 2017 and 2016 have been reclassified to conform to the 2018 presentation. These reclassifications were not material to the Company’s financial statements.
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.
Securities	Securities The Company invests in debt securities. Any sales of debt securities are for the purpose of executing the Company’s asset/liability management strategy, eliminating a perceived credit risk in a specific security or providing liquidity. Debt securities that are being held for indefinite periods of time, or that may be sold as part of the Company’s asset/liability management strategy, to provide liquidity or for other reasons, are classified as available for sale and are stated at estimated fair value. Unrealized gains or losses on debt securities available for sale are reported as a component of stockholders’ equity, net of income tax. Gains or losses from sales of debt securities are based upon the book values of the specific debt securities sold. Debt securities for which the Company has the intent and ability to hold to maturity are classified as held for investment and are stated at cost, adjusted for amortization of premiums and accretion of discounts computed under the interest method. The Company reviews its portfolio of securities for impairment at least quarterly. Impairment is considered to be other-than-temporary if it is likely that all amounts contractually due will not be received for debt securities. When impairment is considered other-than-temporary, the cost basis of the security is written down to fair value, with the impairment charge included in earnings. In evaluating whether the impairment is temporary or other-than-temporary, the Company considers, among other things, the period of time the security has been in an unrealized loss position, and whether the Company has the intent and ability to hold a security for a period of time sufficient to allow for any anticipated recovery in fair value. The Company does not engage in securities trading activities. 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. For periods prior to January 1, 2018, equity securities were classified as available-for-sale and stated at fair value with unrealized gains and losses reported as a separate component of accumulated other comprehensive income (loss), net of tax. Equity securities are reported in other assets on the balance sheet. The Company reviews its portfolio of equity securities for impairment at least quarterly.
Loans	Loans The lending function is governed by written policies and procedures, as determined by senior management and approved by the Board of Directors. The policies and procedures set the standards for lending in each major loan category by collateral type and use of loan proceeds. The objectives of these policies and procedures are to identify profitable markets, determine appropriate risk tolerance levels for each type of loan, establish limits for loan officer approval, set concentration limits, establish loan-to-value thresholds, set repayment terms and loan structure guidelines and adhere to documentation requirements. Interest rate risk is controlled by the use of variable rate provisions, the vast majority of which have a rate floor, limits on fixing rates for longer periods and the use of prepayment penalties. One-to-four family residential real estate loans are made in accordance with underwriting policies and are fully documented. Credit worthiness is assessed based on significant credit characteristics including credit history and residential and employment stability. These loans include first liens, junior liens and home equity lines of credit. The composition of this portfolio is primarily first liens, which comprise approximately 82% of the portfolio, with junior liens comprising approximately 9%, and home equity lines of credit comprising approximately 9%. The Company does not engage in any hybrid loan programs. In addition, the Company does not have any exposure to loans with negative amortization, interest rate carryover or discounting of the initial rates (teaser rates). Loans originated within the Company are stated at the principal amount outstanding, net of unearned interest, loan fees and allowance for loan losses. Interest on all performing loans is recognized, on a simple interest basis, based upon the principal amount outstanding. A loan is placed on nonaccrual status when, in the opinion of management, the future collectability of interest and/or principal is not probable. When interest accrual is discontinued, all unpaid accrued interest is reversed. Interest income is recognized on certain of these loans on a cash basis if the full collection of the remaining principal balance is reasonably expected. Otherwise, interest income is not recognized until the principal balance is fully collected. See Note (5) for loan disclosures. An updated appraisal of the collateral is obtained when a loan is first identified as a problem loan. Appraisals are reviewed annually and are updated as needed, or are updated more frequently if significant changes are believed to have occurred in the collateral or market conditions. Appraisals of other real estate owned are also reviewed and updated consistent with this policy. When a loan deteriorates to the point that the account officer or the Loan Committee concludes it no longer represents a viable asset, it will be charged off. Similarly, any portion of a loan that is deemed to no longer be a viable asset will be charged off. A loan will not be charged off unless such action has been approved by the branch President.
Acquired Loans	Acquired Loans Loans acquired through business combinations since December 2009 are required to be carried at fair value as of the date of the combination. Loans that would have a general allowance for loan losses or have specific evidence of deterioration of credit quality since origination are adjusted to fair value and any allowance for loan losses is eliminated. The difference between the fair value of loans which do not have specific evidence of deterioration of credit quality since origination and their principal balance is recognized in interest income on a level-yield method over the life of the loans. For loans which it is probable, at acquisition, that the Company will be unable to collect all contractually required payments (as determined by the present value of expected future cash flows), the difference between the undiscounted cash flows expected at acquisition and the investment in the loan, or the “accretable yield,” is recognized in interest income on a level-yield method over the life of the loan. Contractually required payments for interest and principal that exceed the undiscounted cash flows expected at acquisition, or the “nonaccretable difference,” are not recognized as yield adjustments or as loss accruals or valuation allowances. Increases in expected cash flows subsequent to the initial investment are recognized prospectively through adjustment of the yield on the loan over its remaining life. Decreases in expected cash flows are recognized as impairments. Any probable loss due to subsequent credit deterioration of the loans since acquisition is provided for in the allowance for loan losses.
Loans Held For Sale	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 the 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 carried at the lower of cost or fair value. Gains or losses recognized upon the sale of the loans are determined on a specific identification basis. The Company does not sell residential mortgage loans with recourse other than obligations under standard representations and warranties or for fraud. These obligations relate to loan performance for the life of the loan. The amount of loans repurchased since the inception of the program is not considered to be material, and therefore, no reserve has been required.
Allowance for Loan Losses	Allowance for Loan Losses The allowance for loan losses is an estimate of probable credit losses related to specifically identified loans and for losses inherent in the portfolio that have been incurred as of the balance sheet date. The allowance for loan losses is increased by provisions charged to operating expense and is reduced by net loan charge-offs. The amount of the allowance for loan losses is based on past loan loss experience, evaluations of known impaired loans, levels of adversely graded loans, general economic conditions and other environmental factors. Loans are considered impaired when, based on current information and events, it is probable the Company will be unable to collect all amounts due in accordance with the original contractual terms of the loan agreement, including scheduled principal and interest payments. Impairment is evaluated in aggregate for smaller-balance loans of a similar nature and on an individual loan basis for other loans. If a loan is impaired, a specific allowance is provided, if necessary, so that the loan is reported net, at the present value of estimated future cash flows using the loan’s existing rate or at the fair value of collateral if repayment is expected primarily from the collateral. Interest payments on impaired loans are typically applied to principal unless collectability of the principal amount is reasonably assured, in which case interest is recognized on a cash basis. Impaired loans, or portions thereof, are charged off when deemed uncollectible.
Nonaccrual Policy	Nonaccrual Policy The Company does not accrue interest on (1) any loan upon which a default of principal or interest has existed for a period of 90 days or over unless the collateral margin or guarantor support are such that full collection of principal and interest are not in doubt, and an orderly plan for collection is in process; and (2) any other loan for which it is expected full collection of principal and interest is not probable. A nonaccrual loan may be restored to an accrual status when none of its principal and interest are past due and unpaid or otherwise becomes well secured and in the process of collection and when prospects for collection of future contractual payments are no longer in doubt. With the exception of a formal debt forgiveness agreement, no loan which has had principal charged-off shall be restored to accrual status unless the charged-off principal has been recovered.
Premises and Equipment	Premises and Equipment Premises and equipment are stated at cost, less accumulated depreciation. Depreciation is charged to operating expense and is computed using the straight-line method over the estimated useful lives of the assets. Maintenance and repairs are charged to expense as incurred while improvements are capitalized. Premises and equipment is tested for impairment if events or changes in circumstances occur that indicate that the carrying amount of any premises and equipment may not be recoverable. Impairment losses are measured by comparing the fair values of the premises and equipment with their recorded amounts. Premises that are identified to be sold are transferred to other real estate owned at the lower of their carrying amounts or their fair values less estimated costs to sell. Any losses on premises identified to be sold are charged to operating expense. When premises and equipment are transferred to other real estate owned, sold, or otherwise retired, the cost and applicable accumulated depreciation are removed from the respective accounts and any resulting gains or losses are reported in the statement of comprehensive income.
Other Real Estate Owned	Other Real Estate Owned Other real estate owned consists of properties acquired through foreclosure proceedings or acceptance of a deed in lieu of foreclosure, and premises held for sale. These properties are carried at the lower of the book values of the related loans or fair values based upon appraisals, less estimated costs to sell. Losses arising at the time of reclassification of such properties from loans to other real estate owned are charged directly to the allowance for loan losses. Any losses on premises identified to be sold are charged to operating expense at the time of transfer from premises to other real estate owned. Losses from declines in value of the properties subsequent to classification as other real estate owned are charged to operating expense.
Intangible Assets and Goodwill	Intangible Assets and Goodwill Core deposit intangibles are amortized on a straight-line basis over the estimated useful lives of seven to ten years and customer relationship intangibles are amortized on a straight-line basis over the estimated useful life of three to eighteen years. Mortgage servicing rights are amortized based on current prepayment assumptions. Goodwill is not amortized, but is evaluated at a reporting unit level at least annually for impairment, or more frequently if other indicators of impairment are present. At least annually in the fourth quarter, intangible assets, excluding mortgage servicing rights, are evaluated for possible impairment. Impairment losses are measured by comparing the fair values of the intangible assets with their recorded amounts. Any impairment losses are reported in the statement of comprehensive income. Mortgage servicing rights are adjusted to fair value periodically, if impaired.
Derivatives	Derivatives The Company recognizes all of its derivative instruments as assets or liabilities in the balance sheet at fair value and recognizes the realized and unrealized change in fair value in the statement of comprehensive income. Income is derived from a fixed pricing spread when customer hedge contracts are immediately offset with counterparty contracts as compensation for administrative costs and credit risk and recognized in other noninterest income.
Insurance Commissions and Fees	Insurance Commissions and Fees Commission revenue is recognized at the later of the billing date or the effective date of the related insurance policies for those accounts billed by the Agency. Commission revenue, for accounts that are directly billed by the insurance company to the insured, is recognized when determinable by the Agency, which is generally when such commissions are received. The Agency also receives contingent commissions from insurance companies as additional incentive for achieving specified premium volume goals and/or loss experience parameters relating to the insurance placed by the Agency. Contingent commissions from insurance companies are recognized when determinable, which is generally when such commissions are received.
Stock-based Compensation	Stock-based Compensation The Company recognizes stock-based compensation as compensation expense in the statement of comprehensive income based on the fair value of the Company’s stock options on the measurement date, which, for the Company, is the date of the grant. 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.
Income Taxes	Income Taxes The Company files a consolidated income tax return with its subsidiaries. Federal and state income tax expense or benefit has been allocated to subsidiaries on a separate return basis. Deferred taxes are recognized under the balance sheet method based upon the future tax consequences of temporary differences between the carrying amounts and tax basis of assets and liabilities, using the tax rates expected to apply to taxable income in the periods when the related temporary differences are expected to be realized. Realization of deferred tax assets is dependent upon the generation of a sufficient level of future taxable income and recoverable taxes paid in prior years. Although realization is not assured, management believes it is more likely than not that all of the deferred tax assets will be realized.
Earnings Per Common Share	Earnings Per Common Share Basic earnings per common share is computed by dividing net income, less any preferred dividends requirement, by the weighted average of common shares outstanding. Diluted earnings per common share reflects the potential dilution that could occur if options, convertible securities or other contracts to issue common stock were exercised or converted into common stock or resulted in the issuance of common stock that then shared in the earnings of the Company.
Comprehensive Income	Comprehensive Income Comprehensive income includes all changes in stockholders’ equity during a period, except those resulting from transactions with stockholders. Besides net income, other components of the Company’s comprehensive income includes the after tax effect of changes in the net unrealized gain/loss on debt securities available for sale.
Statement of Cash Flows	Statement of Cash Flows For purposes of the statement of cash flows, the Company considers cash and due from banks and interest-bearing deposits with banks as cash equivalents.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Standards Adopted During Current Period: In February 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2018-2, Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. ASU 2018-2 allows a reclassification from accumulated other comprehensive income (loss) to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act. ASU 2018-2 is effective for fiscal years beginning after December 15, 2018 with early adoption permitted. The Company elected to early adopt the provisions of ASU 2018-2 and the amount to reclassify was immaterial to the Company’s financial statements. The Company’s policy is to release material stranded tax effects on a specific identification basis. In May 2017, the FASB issued ASU No. 2017-09, “Compensation – Stock Compensation (Topic 718): Scope of Modification Accounting.” The amendments in this update provide guidance about types of changes to the terms of conditions of share-based payment awards that would require an entity to apply modification accounting under ASC 718. ASU 2017-09 was adopted on January 1, 2018 and did not have a significant impact on the Company’s financial statements and no prior periods were adjusted. In January 2017, the FASB issued ASU No. 2017-04, “Intangibles – Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment.” ASU 2017-04 removes the second step of goodwill testing. ASU 2017-04 is effective for fiscal years beginning after December 31, 2019 with early adoption permitted. The Company elected to early adopt ASU 2017-4 and it did not have a significant impact on the Company’s financial statements. In January 2017, the FASB issued ASU No. 2017-01, “Business Combinations (Topic 805): Clarifying the Definition of a Business.” ASU 2017-01 clarifies the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of a business. ASU 2017-01 was adopted on January 1, 2018 and did not have a significant impact on the Company’s financial statements. In October 2016, the FASB issued ASU No. 2016-16, “Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory.” ASU 2016-16 provides guidance stating that an entity should recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. ASU 2016-16 was adopted on January 1, 2018 and did not have a significant impact on the Company’s financial statements and no prior periods were adjusted. In August 2016, the FASB issued ASU No. 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments.” ASU 2016-15 is intended to reduce the diversity in practice around how certain transactions are classified within the statement of cash flows. ASU 2016-15 was adopted on January 1, 2018 and did not have a significant impact on the Company’s financial statements. In January 2016, the FASB issued ASU No. 2016-01, “Financial Instruments – Overall (Subtopic 825-10).” ASU 2016-01 requires all equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) to be measured at fair value with changes in the fair value recognized through net income. The adoption of the guidance resulted in a $618,000 decrease to retained earnings and a $618,000 increase to accumulated other comprehensive income. Additional income of $48,900 was recorded in the consolidated statement of comprehensive income during 2018 as a result of changes to the accounting for equity investments. Further, the Company’s securities disclosures in Note (4) have been revised to exclude equity investments and fair value disclosures in Note (20) have incorporated the revised disclosure requirements for financial investments. In addition, equity securities of $5.7 million were reclassed from securities to other assets on the Company’s 2017 balance sheet to conform to the current presentation. ASU 2016-01 also emphasizes the existing requirement to use exit prices to measure fair value for disclosure purposes and clarifies that entities should not make use of a practicability exception in determining the fair value of loans. Accordingly, we refined the calculation used to determine the disclosed fair value of loans held for investment as part of adopting this standard. The refined calculation did not have a significant impact on fair value disclosures. In January 2014, the FASB issued ASU No. 2014-09, “Revenue from Contracts with Customers (Topic 606).” ASU 2014-09 implements a comprehensive new revenue recognition standard that will supersede substantially all existing revenue recognition guidance. The new standard’s core principle is that a company will recognize revenue when it transfers promised goods or services to customers in a manner that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. The guidance does not apply to revenue associated with financial instruments, including loans and securities that are accounted for under other GAAP, which comprises a significant portion of the Company’s revenue stream. ASU 2014-09 was adopted on January 1, 2018 and did not have a significant impact on the Company’s financial statements. 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. 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 models 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 Company expects to adopt the standard in the first quarter of 2020. In February 2016, the FASB issued ASU No. 2016-02, “Leases - (Topic 842).” ASU 2016-02 requires that lessees recognize on the balance sheet the assets and liabilities for the rights and obligations created by leases. The amendments are effective for annual periods, and interim reporting periods within those annual periods, beginning after December 15, 2018. The Company .

Cash, Due from Banks, Interes_2

Cash, Due from Banks, Interest-Bearing Deposits and Federal Funds Sold (Tables)	12 Months Ended
	Dec. 31, 2018
Cash And Cash Equivalents [Abstract]
Summary of Average Amount of Required Reserves	The average amount of required reserves for each of the years ended December 31, 2018 and 2017 is included in the following table: December 31, 2018 2017 (Dollars in thousands) Vault cash and funds on deposit with the Federal Reserve Bank $ 1,299,872 $ 1,639,058 Average required Reserves 45,195 44,485

Securities (Tables)

Securities (Tables)	12 Months Ended
	Dec. 31, 2018
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 (Dollars in thousands) 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 December 31, 2017 Mortgage backed securities (1) $ 187 $ 10 $ — $ 197 States and political subdivisions 1,605 3 (2 ) 1,606 Other securities 500 — — 500 Total $ 2,292 $ 13 $ (2 ) $ 2,303
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 (Dollars in thousands) 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 December 31, 2017 U.S. treasuries $ 314,905 $ — $ (2,103 ) $ 312,802 U.S. federal agencies 89,098 82 (329 ) 88,851 Mortgage backed securities (1) 18,358 204 (586 ) 17,976 States and political subdivisions 41,937 554 (121 ) 42,370 Total $ 464,298 $ 840 $ (3,139 ) $ 461,999 (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. December 31, 2018 2017 Amortized Cost Estimated Fair Value Amortized Cost Estimated Fair Value (Dollars in thousands) Held for Investment Contractual maturity of debt securities: Within one year $ 495 $ 495 $ 1,036 $ 1,034 After one year but within five years 369 370 623 627 After five years but within ten years 562 565 625 633 After ten years 2 3 8 9 Total $ 1,428 $ 1,433 $ 2,292 $ 2,303 Available for Sale Contractual maturity of debt securities: Within one year $ 411,256 $ 410,327 $ 113,225 $ 112,974 After one year but within five years 313,416 311,924 289,038 287,058 After five years but within ten years 7,524 7,685 6,222 6,500 After ten years 41,378 40,768 55,813 55,467 Total debt securities $ 773,574 $ 770,704 $ 464,298 $ 461,999
Proceeds from Sales and Realized Securities Losses, on Available for Sale Debt Securities	The following is a detail of proceeds from sales and realized securities losses, on available for sale debt securities: Year Ended December 31, 2018 2017 2016 (Dollars Proceeds $ 31,285 $ — $ — Gross losses realized 109 — —
Company's Book Value of Pledged Debt Securities	The following table is a summary of the Company’s book value of debt securities that were pledged as collateral for public funds on deposit, repurchase agreements and for other purposes as required or permitted by law: December 31, 2018 2017 (Dollars Book value of pledged securities $ 472,053 $ 440,069
Summary of Debt Securities with Unrealized Losses, Segregated by Duration of Unrealized Loss	The following table summarizes debt securities with unrealized losses, segregated by the duration of the unrealized loss, at December 31, 2018 and 2017 respectively: Less than 12 Months More than 12 Months Total Estimated Fair Value Unrealized Losses Estimated Fair Value Unrealized Losses Estimated Fair Value Unrealized Losses (Dollars in thousands) December 31, 2018 Held for Investment Mortgage backed securities $ — $ — $ 4 $ — $ 4 $ — Total $ — $ — $ 4 $ — $ 4 $ — Available for Sale U.S. treasuries $ 296,438 $ 90 $ 261,639 $ 3,434 $ 558,077 $ 3,524 U.S. federal agencies 1,705 7 27,035 153 28,740 160 Mortgage backed securities 1 — 13,444 573 13,445 573 States and political subdivisions 1,593 3 11,527 109 13,120 112 Total $ 299,737 $ 100 $ 313,645 $ 4,269 $ 613,382 $ 4,369 December 31, 2017 Held for Investment Mortgage backed securities $ — $ — $ 7 $ — $ 7 $ — States and political subdivisions 65 — 478 2 543 2 Total $ 65 $ — $ 485 $ 2 $ 550 $ 2 Available for Sale U.S. treasuries $ 283,302 $ 1,653 $ 29,500 $ 450 $ 312,802 $ 2,103 U.S. federal agencies 3,499 8 59,220 321 62,719 329 Mortgage backed securities 1 — 14,475 586 14,476 586 States and political subdivisions 21,300 114 585 7 21,885 121 Total $ 308,102 $ 1,775 $ 103,780 $ 1,364 $ 411,882 $ 3,139

Loans and Allowance for Loan _2

Loans and Allowance for Loan Losses (Tables)	12 Months Ended
	Dec. 31, 2018
Receivables [Abstract]
Schedule of Loans Outstanding by Category	The following is a schedule of loans outstanding by category: December 31, 2018 2017 Amount Percent Amount Percent (Dollars in thousands) Commercial and financial: Commercial and industrial $ 1,032,787 20.76 % $ 995,207 21.08 % Oil & gas production and equipment 94,729 1.90 95,574 2.02 Agriculture 136,313 2.74 141,249 2.99 State and political subdivisions: Taxable 76,211 1.53 73,827 1.56 Tax-exempt 48,415 0.97 48,626 1.03 Real estate: Construction 451,224 9.07 437,277 9.26 Farmland 219,241 4.41 195,162 4.13 One to four family residences 979,170 19.68 875,766 18.55 Multifamily residential properties 65,949 1.33 46,030 0.98 Commercial 1,506,937 30.28 1,487,927 31.51 Consumer 328,069 6.59 284,373 6.02 Other (not classified above) 36,931 0.74 40,977 0.87 Total loans $ 4,975,976 100.00 % $ 4,721,995 100.00 %
Summary of Nonperforming and Restructured Assets	The following is a summary of nonperforming and restructured assets: December 31, 2018 2017 (Dollars in thousands) Past due 90 days or more and still accruing $ 1,916 $ 2,893 Nonaccrual 22,603 31,943 Restructured 13,188 4,720 Total nonperforming and restructured loans 37,707 39,556 Other real estate owned and repossessed assets 6,873 4,424 Total nonperforming and restructured assets $ 44,580 $ 43,980
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. December 31, 2018 2017 (Dollars in thousands) Real estate: Non-residential real estate owner occupied $ 838 $ 1,108 Non-residential real estate other 187 9,809 Residential real estate permanent mortgage 954 781 Residential real estate all other 5,488 3,980 Commercial and financial: Non-consumer non-real estate 5,682 7,785 Consumer non-real estate 437 250 Other loans 490 5,596 Acquired loans 8,527 2,634 Total $ 22,603 $ 31,943
Age Analysis of Past Due Loans Segregated by Class of Loans	The following table presents an age analysis of past due loans, segregated by class of loans: Age Analysis of Past Due Loans 30-59 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 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 As of December 31, 2017 Real estate: Non-residential real estate owner occupied $ 998 $ 68 $ 977 $ 2,043 $ 639,575 $ 641,618 $ 84 Non-residential real estate other 2,905 271 2,112 5,288 1,121,303 1,126,591 432 Residential real estate permanent mortgage 2,211 403 977 3,591 326,743 330,334 584 Residential real estate all other 1,739 749 1,377 3,865 781,790 785,655 973 Commercial and financial: Non-consumer non-real estate 2,210 706 1,785 4,701 1,279,704 1,284,405 403 Consumer non-real estate 2,085 670 293 3,048 285,872 288,920 194 Other loans 506 103 3,916 4,525 139,920 144,445 — Acquired loans 753 192 713 1,658 118,369 120,027 223 Total $ 13,407 $ 3,162 $ 12,150 $ 28,719 $ 4,693,276 $ 4,721,995 $ 2,893
Impaired Loans Segregated by Class of Loans	The following table presents impaired loans, segregated by class of loans. During the year ended December 31, 2018 no material amount of interest income was recognized on impaired loans subsequent to their classification as impaired. During the year ended December 31, 2017, $2.3 million 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 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 As of December 31, 2017 Real estate: Non-residential real estate owner occupied $ 2,011 $ 1,945 $ 141 $ 1,858 Non-residential real estate other 10,323 10,240 496 3,975 Residential real estate permanent mortgage 1,745 1,542 146 1,440 Residential real estate all other 5,837 5,549 2,135 5,258 Commercial and financial: Non-consumer non-real estate 18,101 11,158 2,412 11,131 Consumer non-real estate 545 514 127 541 Other loans 6,092 5,595 178 7,439 Acquired loans 4,737 3,145 12 3,539 Total $ 49,391 $ 39,688 $ 5,647 $ 35,181
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 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 As of December 31, 2017 Real estate: Non-residential real estate owner occupied $ 520,641 $ 105,696 $ 13,852 $ 1,429 $ — $ 641,618 Non-residential real estate other 931,295 178,282 14,290 2,724 — 1,126,591 Residential real estate permanent mortgage 289,200 33,033 6,352 1,749 — 330,334 Residential real estate all other 621,401 149,201 9,418 5,635 — 785,655 Commercial and financial: Non-consumer non-real estate 1,018,172 234,884 24,322 6,997 30 1,284,405 Consumer non-real estate 268,826 17,499 2,038 557 — 288,920 Other loans 136,617 5,668 1,203 957 — 144,445 Acquired loans 65,685 34,418 17,113 2,811 — 120,027 Total $ 3,851,837 $ 758,681 $ 88,588 $ 22,859 $ 30 $ 4,721,995
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) As of December 31, 2018 Real estate: Non-residential real estate owner occupied $ 6,195 $ (282 ) $ 17 $ (265 ) $ 398 $ 6,328 Non-residential real estate other 10,519 (93 ) 41 (52 ) 560 11,027 Residential real estate permanent mortgage 3,226 (174 ) 26 (148 ) 183 3,261 Residential real estate all other 9,672 (395 ) 106 (289 ) 1,290 10,673 Commercial and financial: Non-consumer non-real estate 15,334 (2,257 ) 92 (2,165 ) (18 ) 13,151 Consumer non-real estate 2,793 (1,066 ) 245 (821 ) 1,093 3,065 Other loans 2,481 (16 ) 361 345 (403 ) 2,423 Acquired loans 1,446 (720 ) 36 (684 ) 699 1,461 Total $ 51,666 $ (5,003 ) $ 924 $ (4,079 ) $ 3,802 $ 51,389 As of December 31, 2017 Real estate: Non-residential real estate owner occupied $ 5,602 $ (74 ) $ 6 $ (68 ) $ 661 $ 6,195 Non-residential real estate other 10,793 (47 ) 16 (31 ) (243 ) 10,519 Residential real estate permanent mortgage 3,129 (373 ) 25 (348 ) 445 3,226 Residential real estate all other 8,622 (330 ) 66 (264 ) 1,314 9,672 Commercial and financial: Non-consumer non-real estate 12,421 (1,344 ) 1,033 (311 ) 3,224 15,334 Consumer non-real estate 2,804 (913 ) 180 (733 ) 722 2,793 Other loans 4,045 (3,727 ) 23 (3,704 ) 2,140 2,481 Acquired loans 1,277 (157 ) 77 (80 ) 249 1,446 Total $ 48,693 $ (6,965 ) $ 1,426 $ (5,539 ) $ 8,512 $ 51,666
Allowance for Loan Losses Outstanding by Impairment Methodology	The following table details the amount of ALL by class of loans for the period presented, on the basis of the impairment methodology used by the Company. ALL December 31, 2018 December 31, 2017 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 $ 669 $ 5,659 $ 656 $ 5,539 Non-residential real estate other 1,119 9,908 751 9,768 Residential real estate permanent mortgage 505 2,756 483 2,743 Residential real estate all other 3,413 7,260 2,761 6,911 Commercial and financial: Non-consumer non-real estate 2,114 11,037 4,651 10,683 Consumer non-real estate 374 2,691 429 2,364 Other loans 65 2,358 133 2,348 Acquired loans — 1,461 12 1,434 Total $ 8,259 $ 43,130 $ 9,876 $ 41,790
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 December 31, 2018 December 31, 2017 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 $ 17,846 $ 608,775 $ — $ 15,281 $ 626,337 $ — Non-residential real estate other 25,333 1,120,795 — 17,013 1,109,578 — Residential real estate permanent mortgage 9,026 319,676 — 8,100 322,234 — Residential real estate all other 21,285 806,219 — 15,052 770,603 — Commercial and financial: Non-consumer non-real estate 19,432 1,264,222 — 31,349 1,253,056 — Consumer non-real estate 3,093 323,769 — 2,600 286,320 — Other loans 209 141,700 — 764 143,681 — Acquired loans 22,132 265,084 7,380 14,464 100,106 5,457 Total $ 118,356 $ 4,850,240 $ 7,380 $ 104,623 $ 4,611,915 $ 5,457
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: Year ended December 31, 2018 2017 2016 (Dollars in thousands) Other real estate owned $ 5,437 $ 2,889 $ 2,553 Repossessed assets 1,122 1,242 1,402 Total $ 6,559 $ 4,131 $ 3,955
Related Party Loans	A summary of these loans is as follows: Year Ended December 31, Balance Beginning of the Period Additions Collections/ Terminations Balance End of the Period (Dollars in thousands) 2018 $ 24,001 $ 7,986 $ (12,096 ) $ 19,891 2017 27,486 7,350 (10,835 ) 24,001 2016 37,577 16,133 (26,224 ) 27,486

Premises and Equipment, Net a_2

Premises and Equipment, Net and Other Assets (Tables)	12 Months Ended
	Dec. 31, 2018
Property Plant And Equipment [Abstract]
Summary of Premises and Equipment by Classification	The following is a summary of premises and equipment by classification: December 31, Estimated Useful Lives 2018 2017 (Dollars in thousands) Land $ 35,434 $ 34,833 Buildings 10 to 40 years 181,182 145,051 Furniture, fixtures and equipment 3 to 15 years 75,138 69,915 Accumulated depreciation (117,392 ) (115,711 ) Premises and equipment, net $ 174,362 $ 134,088

Intangible Assets and Goodwill

Intangible Assets and Goodwill (Tables)	12 Months Ended
	Dec. 31, 2018
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 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 As of December 31, 2017 Core deposit intangibles $ 17,447 $ (8,451 ) $ 8,996 Customer relationship intangibles 5,699 (3,767 ) 1,932 Mortgage servicing intangibles 439 (285 ) 154 Total $ 23,585 $ (12,503 ) $ 11,082
Estimated Amortization of Intangible Assets	Estimated amortization of intangible assets for the next five years, as of December 31, 2018, is as follows (dollars in thousands): Estimated Amortization 2019 $ 3,056 2020 2,975 2021 2,246 2022 1,935 2023 1,811
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) Year Ended December 31, 2018 Balance at beginning of period $ 8,078 $ 39,876 $ 5,464 $ 624 $ 54,042 Acquisitions 5,689 20,018 — — 25,707 Balance at end of period $ 13,767 $ 59,894 $ 5,464 $ 624 $ 79,749 Year Ended December 31, 2017 Balance at beginning and end of period $ 8,078 $ 39,876 $ 5,464 $ 624 $ 54,042

Time Deposits (Tables)

Time Deposits (Tables)	12 Months Ended
	Dec. 31, 2018
Deposits [Abstract]
Schedule of Maturities of Time Deposits	At December 31, 2018, the scheduled maturities of all time deposits are as follows (Dollars in thousands): 2019 $ 458,378 2020 122,648 2021 53,661 2022 39,979 2023 31,276 Thereafter 4 Total $ 705,946
Summary of Large time Deposits and time Deposits Meet or Exceed Current FDIC Insurance Limit for Periods Presented	The following table is a summary of large time deposits and time deposits that meet or exceed the current FDIC insurance limit for the periods presented: December 31, 2018 2017 (Dollars in thousands) Time deposits of $100,000 or more $ 349,918 $ 319,811 Time deposits of $250,000 or more 132,957 122,391

Short-Term Borrowings (Tables)

Short-Term Borrowings (Tables)	12 Months Ended
	Dec. 31, 2018
Short Term Borrowings [Abstract]
Summary of Short-Term Borrowings	The following is a summary of short-term borrowings: December 31, 2018 2017 (Dollars in thousands) Federal funds purchased $ 1,675 $ 900 Weighted average interest rate 1.84 % 0.97 % End of period interest rate 2.30 % 1.38 %

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Components of the Company's Income Tax Expense (Benefit)	The components of the Company’s income tax expense (benefit) are as follows: Year Ended December 31, 2018 2017 2016 (Dollars in thousands) Current taxes: Federal $ 23,700 $ 39,569 $ 34,003 State 7,083 5,914 5,308 Deferred taxes 3,155 4,383 (2,048 ) Total income taxes $ 33,938 $ 49,866 $ 37,263
Reconciliation of Tax Expense at the Federal Statutory Tax Rate	Income tax expense for 2017 was impacted by the write-down of net deferred tax asset of $4.3 million resulting from the federal tax rate change under the Tax Cuts and Jobs Act, enacted December 22, 2017. A reconciliation of tax expense at the federal statutory tax rate applied to income before taxes is presented in the following table. The federal statutory tax rate was 21% in 2018 and 35% in 2017 and 2016: Year Ended December 31, 2018 2017 2016 (Dollars in thousands) Tax expense at the federal statutory tax rate $ 33,546 $ 47,708 $ 37,778 Increase (decrease) in tax expense from: Tax-exempt income, net (510 ) (829 ) (756 ) Modified endowment life contracts (558 ) (921 ) (852 ) Share based compensation excess tax benefit (917 ) (2,354 ) — State tax expense, net of federal tax benefit 5,595 3,840 3,250 Write-down of net deferred tax asset — 4,331 — Utilization of tax credits: New markets tax credits (1,422 ) (1,151 ) (1,254 ) Low-income housing tax credits, net of amortization (1,273 ) (1,589 ) (1,424 ) Other tax credits — — (319 ) Other, net (523 ) 831 840 Total tax expense $ 33,938 $ 49,866 $ 37,263
Summary of Net Deferred Tax Asset Reported in Other Assets	The net deferred tax asset consisted of the following and is reported in other assets: December 31, 2018 2017 (Dollars in thousands) Provision for loan losses $ 13,089 $ 13,123 Unrealized net losses on securities 731 739 Write-downs of other real estate owned 462 473 Deferred compensation 2,209 2,113 Stock-based compensation 1,448 1,351 Investments in partnership interests 4,274 3,758 Other 963 275 Gross deferred tax assets 23,176 21,832 Premium on securities of banks acquired (185 ) (219 ) Intangibles (5,376 ) (3,359 ) Basis difference related to tax credits (2,560 ) (2,713 ) Depreciation (8,484 ) (4,563 ) Leveraged lease — (821 ) Prepaid expense deducted (1,178 ) (887 ) Other (181 ) (180 ) Gross deferred tax liabilities (17,964 ) (12,742 ) Net deferred tax asset $ 5,212 $ 9,090

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2018
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) Year Ended December 31, 2018 Outstanding at December 31, 2017 1,273,625 $ 25.90 Options granted 72,000 56.47 Options exercised (123,925 ) 17.42 Options canceled, forfeited, or expired (5,000 ) 48.02 Outstanding at December 31, 2018 1,216,700 28.48 9.53Yrs $ 26,066 Exercisable at December 31, 2018 601,700 21.53 7.12Yrs $ 17,070 Year Ended December 31, 2017 Outstanding at December 31, 2016 1,414,900 $ 22.46 Options granted 121,500 48.26 Options exercised (262,775 ) 17.73 Outstanding at December 31, 2017 1,273,625 25.90 9.73Yrs $ 32,165 Exercisable at December 31, 2017 566,625 20.07 6.92Yrs $ 17,611
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: Year Ended December 31, 2018 2017 2016 (Dollars in thousands) Total intrinsic value of options exercised $ 4,810 $ 8,389 $ 12,230 Cash received from options exercised 2,159 4,660 9,720 Tax benefit realized from options exercised 1,225 3,245 4,731
Stock-based Employee Compensation Expense	The following table is a summary of the Company’s recorded stock-based compensation expense: Year Ended December 31, 2018 2017 206 (Dollars in thousands) Stock-based compensation expense $ 1,352 $ 1,180 $ 1,636 Tax benefit 345 301 633 Stock-based compensation expense, net of tax $ 1,007 $ 879 $ 1,003
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: December 31, 2018 (Dollars in thousands) Unearned stock-based compensation expense $ 3,319
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: Year Ended December 31, 2018 2017 2016 Weighted average grant-date fair value per share of options granted $ 14.71 $ 11.87 $ 5.96 Risk-free interest rate 2.55 to 3.05% 2.15 to 2.40% 1.46 to 2.02% Dividend yield 2.00 % 2.00 % 2.00 % Stock price volatility 23.05 to 23.95% 22.57 to 24.18% 20.41 to 21.78% Expected term 10 Yrs 10 Yrs 10 Yrs
Summary of Accumulated Stock Units	A summary of the accumulated stock units is as follows: December 31, 2018 2017 Accumulated stock units 143,347 138,768 Average price $ 24.91 $ 22.84

Retirement Plans (Tables)

Retirement Plans (Tables)	12 Months Ended
	Dec. 31, 2018
Compensation And Retirement Disclosure [Abstract]
Aggregate Amounts of Contributions to the 401(k) and ESOP Plans	The aggregate amounts of contributions by the Company to the 401(k) and ESOP plans are shown in the following table: December 31, 2018 2017 2016 (Dollars in thousands) 401(k) contributions $ 2,465 $ 2,229 $ 2,074 ESOP contributions 4,073 2,645 2,352 Total contributions $ 6,538 $ 4,874 $ 4,426

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Summary of Authorized Outstanding Preferred and Common Stock	As of December 31, 2018, 2017 and 2016 the Company’s authorized and outstanding preferred and common stock was as follows: No. of Shares Authorized at No. of Shares Outstanding at December 31, Class of Stock December 31, 2018 2018 2017 2016 Par Value Per Share Dividends Voting Rights Senior Preferred 10,000,000 — — — $ 1.00 As declared Voting 10% Cumulative Preferred 900,000 — — — 5.00 As declared Non-voting Common 40,000,000 32,603,926 31,894,563 31,621,870 1.00 As declared Voting
Summary of Shares Repurchased Under Stock Purchase Program	The following table is a summary of the shares under the program: Year Ended December 31, 2018 2017 2016 Number of shares repurchased 151,264 — 200,000 Average price of shares repurchased $ 52.32 $ — $ 27.62 Shares remaining to be repurchased 148,736 300,000 300,000
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 December 31, 2018: Total Capital (to Risk Weighted Assets)- BancFirst Corporation $ 886,190 16.29 % $ 435,208 8.00% $ 537,210 9.875 % N/A N/A BancFirst 765,487 14.09 % 434,573 8.00% 536,426 9.875 % $ 543,216 10.00 % Common Equity Tier 1 Capital (to Risk Weighted Assets)- BancFirst Corporation $ 808,801 14.87 % $ 244,804 4.50% $ 346,806 6.375 % N/A N/A BancFirst 694,098 12.78 % 244,447 4.50% 346,300 6.375 % $ 353,090 6.50 % Tier 1 Capital (to Risk Weighted Assets)- BancFirst Corporation $ 834,801 15.35 % $ 326,406 6.00% $ 428,408 7.875 % N/A N/A BancFirst 714,098 13.15 % 325,930 6.00% 427,783 7.875 % $ 434,573 8.00 % Tier 1 Capital (to Total Assets)- BancFirst Corporation $ 834,801 11.09 % $ 301,116 4.00% N/A N/A N/A N/A BancFirst 714,098 9.49 % 300,855 4.00% N/A N/A $ 376,069 5.00 % As of December 31, 2017: Total Capital (to Risk Weighted Assets)- BancFirst Corporation $ 797,015 15.62 % $ 408,234 8.00% $ 472,020 9.250 % N/A N/A BancFirst 714,964 14.03 % 407,698 8.00% 471,401 9.250 % $ 509,622 10.00 % Common Equity Tier 1 Capital (to Risk Weighted Assets)- BancFirst Corporation $ 714,349 14.00 % $ 229,632 4.50% $ 293,418 5.750 % N/A N/A BancFirst 643,298 12.62 % 229,330 4.50% 293,033 5.750 % $ 331,255 6.50 % Tier 1 Capital (to Risk Weighted Assets)- BancFirst Corporation $ 745,349 14.61 % $ 306,175 6.00% $ 369,962 7.250 % N/A N/A BancFirst 663,298 13.02 % 306,773 6.00% 369,476 7.250 % $ 407,698 8.00 % Tier 1 Capital (to Total Assets)- BancFirst Corporation $ 745,349 10.44 % $ 285,444 4.00% N/A N/A N/A N/A BancFirst 663,298 9.31 % 285,101 4.00% N/A N/A $ 356,677 5.00 %

Net Income Per Common Share (Ta

Net Income Per Common Share (Tables)	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Basic and Diluted Net Income Per Common Share	Basic and diluted net income per common share are calculated as follows: Income (Numerator) Shares (Denominator) Per Share Amount (Dollars in thousands, except per share data) Year Ended December 31, 2018 Basic Income available to common stockholders $ 125,814 32,689,228 $ 3.85 Effect of stock options — 741,486 Diluted Income available to common stockholders plus assumed exercises of stock options $ 125,814 33,430,714 $ 3.76 Year Ended December 31, 2017 Basic Income available to common stockholders $ 86,439 31,813,572 $ 2.72 Effect of stock options — 754,533 Diluted Income available to common stockholders plus assumed exercises of stock options $ 86,439 32,568,105 $ 2.65 Year Ended December 31, 2016 Basic Income available to common stockholders $ 70,674 31,230,340 $ 2.27 Effect of stock options — 592,184 Diluted Income available to common stockholders plus assumed exercises of stock options $ 70,674 31,822,524 $ 2.22
Average Exercise Price of Options Excluded from Computation of Diluted Net Income Per Common Share	The following table shows the number and average exercise price of options that were excluded from the computation of diluted net income per common share for each year because the options were anti-dilutive for the period. Shares Average Exercise December 31, 2018 92,738 $ 53.17 December 31, 2017 55,337 46.86 December 31, 2016 294,438 30.25

Condensed Parent Company Fina_2

Condensed Parent Company Financial Statements (Tables)	12 Months Ended
	Dec. 31, 2018
Condensed Financial Information Of Parent Company Only Disclosure [Abstract]
Summary of Balance Sheet of Parent Company	BALANCE SHEETS December 31, 2018 2017 (Dollars in thousands) ASSETS Cash $ 105,089 $ 67,917 Investments in subsidiaries 822,336 737,031 Goodwill 624 624 Dividends receivable 11,058 7,788 Other assets 958 1,401 Total assets $ 940,065 $ 814,761 LIABILITIES AND STOCKHOLDERS’ EQUITY Other liabilities $ 10,472 $ 7,173 Junior subordinated debentures 26,804 31,959 Stockholders’ equity 902,789 775,629 Total liabilities and stockholders’ equity $ 940,065 $ 814,761
Summary of Income Statement of Parent Company	STATEMENTS OF INCOME Year Ended December 31, 2018 2017 2016 (Dollars in thousands) OPERATING INCOME Dividends from subsidiaries $ 38,326 $ 29,455 $ 28,175 Interest on interest-bearing deposits 1,151 291 160 Other 16 3 3 Total operating income 39,493 29,749 28,338 OPERATING EXPENSE Interest 2,172 2,122 2,096 Other 698 770 583 Total operating expense 2,870 2,892 2,679 Income before taxes and equity in undistributed earnings of subsidiaries 36,623 26,857 25,659 Allocated income tax benefit 3,093 3,295 1,244 Income before equity in undistributed earnings of subsidiaries 39,716 30,152 26,903 Equity in undistributed earnings of subsidiaries 87,404 57,429 44,172 Amortization of stock-based compensation arrangements of subsidiaries (1,306 ) (1,142 ) (401 ) Net income $ 125,814 $ 86,439 $ 70,674
Summary of Cash Flow of Parent Company	STATEMENTS OF CASH FLOW Year Ended December 31, 2018 2017 2016 (Dollars in thousands) CASH FLOWS FROM OPERATING ACTIVITIES Net income $ 125,814 $ 86,439 $ 70,674 Adjustments to reconcile to net cash provided by operating activities: Equity in undistributed earnings of subsidiaries (87,404 ) (57,429 ) (44,172 ) Amortization of stock-based compensation arrangements of subsidiaries 1,306 1,142 401 Other, net (2,621 ) 569 136 Net cash provided by operating activities 37,095 30,721 27,039 INVESTING ACTIVITIES Net cash provided by acquisitions 41,347 — — Payments for investments in subsidiaries — (502 ) — Other, net (174 ) 100 — Net cash provided by (used in) investing activities 41,173 (402 ) — FINANCING ACTIVITIES Issuance of common stock 2,238 4,844 13,354 Common stock acquired (7,914 ) — (5,523 ) Cash dividends paid (30,265 ) (24,783 ) (22,770 ) Redemption of Junior Subordinated debentures (5,155 ) — — Net cash used for financing activities (41,096 ) (19,939 ) (14,939 ) Net increase in cash 37,172 10,380 12,100 Cash and due from banks at the beginning of the period 67,917 57,537 45,437 Cash and due from banks at the end of the period $ 105,089 $ 67,917 $ 57,537 SUPPLEMENTAL DISCLOSURE Cash paid during the period for interest $ 2,171 $ 2,122 $ 2,096 Cash received during the period for income taxes, net $ 3,647 $ 4,643 $ 5,031

Commitments and Contingent Li_2

Commitments and Contingent Liabilities (Tables)	12 Months Ended
	Dec. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Summary of Financial Instruments with Off-Balance-Sheet Risks	The amounts of financial instruments with off-balance-sheet risk are as follows: December 31, 2018 2017 (Dollars in thousands) Loan commitments $ 1,232,996 $ 1,050,686 Stand-by letters of credit 56,096 57,074
Summary of Future Minimum Rental Payments Under Lease	Future minimum lease payments required under operating leases that have an initial or remaining non-cancelable lease term in excess of one year at December 31, 2018, were as follows (Dollars in thousands): 2019 $ 1,049 2020 789 2021 569 2022 369 2023 60 Later years 499 Total $ 3,335
Summary of Rental Expense	Rental expense on all operating leases, including those rented on a monthly or temporary basis were as follows (Dollars in thousands): Year Ending December 31: 2018 $ 1,857 2017 1,597 2016 1,524

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2018
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 December 31, 2018 and 2017, 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) 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 Equity securities — — 7,521 7,521 Derivative assets — 252 — 252 Derivative liabilities — 238 — 238 December 31, 2017 Securities available for sale: U.S. Treasury $ 312,802 $ — $ — $ 312,802 U.S. federal agencies — 88,851 — 88,851 Mortgage-backed securities — 3,509 14,467 17,976 States and political subdivisions — 42,370 — 42,370 Equity securities — — 5,704 5,704 Derivative assets — 295 — 295 Derivative liabilities — 261 — 261
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 years ended December 31, 2018 and 2017 were as follows: Twelve Months Ended December 31, 2018 2017 (Dollars in thousands) Balance at the beginning of the year $ 20,171 $ 21,385 Purchases 3,190 1,668 Settlements (2,446 ) (722 ) Sales (75 ) (5,412 ) Gains included in earnings 118 4,060 Total unrealized gains/(losses) 6 (808 ) Balance at the end of the period $ 20,964 $ 20,171
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 December 31, 2018 Impaired loans (less specific allowance) $ 34,396 Repossessed assets 183 Other real estate owned 4,683 As of and for the Year-to-date Period Ended December 31, 2017 Impaired loans (less specific allowance) $ 34,041 Repossessed assets 288 Other real estate owned 1,995
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: December 31, 2018 2017 Carrying Amount Fair Value Carrying Amount Fair Value (Dollars in thousands) FINANCIAL ASSETS Level 2 inputs: Cash and cash equivalents $ 1,424,255 $ 1,424,255 $ 1,758,575 $ 1,758,575 Securities held for investment 928 933 1,792 1,803 Loans held for sale 8,174 8,174 6,173 6,173 Level 3 inputs: Securities held for investment 500 500 500 500 Loans, net of allowance for loan losses 4,924,587 4,901,159 4,670,329 4,663,608 FINANCIAL LIABILITIES Level 2 inputs: Deposits 6,605,495 6,713,542 6,415,045 6,490,309 Short-term borrowings 1,675 1,675 900 900 Junior subordinated debentures 26,804 29,549 31,959 34,661 OFF-BALANCE SHEET FINANCIAL INSTRUMENTS Loan commitments 2,158 1,839 Letters of credit 421 428

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2018
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) December 31, 2018 Net interest income $ 84,043 $ 170,096 $ 5,341 $ 996 $ — $ 260,476 Provision for loan losses 79 4,178 (466 ) 11 — 3,802 Noninterest income 16,625 60,004 37,743 137,364 (126,537 ) 125,199 Depreciation and amortization 2,364 9,092 588 1,502 — 13,546 Other expenses 36,873 106,674 24,895 42,319 (2,186 ) 208,575 Income before taxes $ 61,352 $ 110,156 $ 18,067 $ 94,528 $ (124,351 ) $ 159,752 Total assets $ 2,743,876 $ 4,892,946 $ 84,706 $ 861,782 $ (1,009,052 ) $ 7,574,258 Capital expenditures $ 3,003 $ 21,393 $ 1,035 $ 26,432 $ — $ 51,863 December 31, 2017 Net interest income (expense) $ 74,274 $ 147,731 $ 5,770 $ (636 ) $ — $ 227,139 Provision for loan losses 2,457 4,442 1,767 (154 ) — 8,512 Noninterest income 15,698 54,353 37,842 97,368 (87,191 ) 118,070 Depreciation and amortization 2,192 7,790 584 1,225 — 11,791 Other expenses 35,488 93,619 24,474 36,531 (1,511 ) 188,601 Income before taxes $ 49,835 $ 96,233 $ 16,787 $ 59,130 $ (85,680 ) $ 136,305 Total assets $ 2,552,024 $ 4,544,196 $ 117,332 $ 885,590 $ (845,986 ) $ 7,253,156 Capital expenditures $ 3,606 $ 12,334 $ 64 $ 2,003 $ — $ 18,007 December 31, 2016 Net interest income (expense) $ 63,519 $ 135,508 $ 6,132 $ (1,331 ) $ — $ 203,828 Provision for loan losses 2,229 7,509 1,653 128 — 11,519 Noninterest income 16,372 57,745 29,711 75,415 (72,211 ) 107,032 Depreciation and amortization 2,341 8,281 510 1,251 — 12,383 Other expenses 34,130 96,627 22,216 26,375 (327 ) 179,021 Income before taxes $ 41,191 $ 80,836 $ 11,464 $ 46,330 $ (71,884 ) $ 107,937 Total assets $ 2,493,096 $ 4,412,174 $ 83,594 $ 803,810 $ (773,722 ) $ 7,018,952 Capital expenditures $ 1,525 $ 7,738 $ 125 $ 1,447 $ — $ 10,835

Selected Quarterly Financial _2

Selected Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Summary of the Unaudited Quarterly Results of Operations	A summary of the unaudited quarterly results of operations for the years ended December 31, 2018 and 2017 is as follows: Quarter Fourth Third Second First (Dollars in thousands, except per share data) 2018 Net interest income $ 66,888 $ 65,673 $ 64,880 $ 63,035 Provision for loan losses 1,516 747 1,225 314 Securities transactions 10 (64 ) 115 (14 ) Noninterest income 31,851 32,801 30,437 30,110 Noninterest expense 56,166 55,809 54,256 55,890 Net income 32,725 32,883 30,586 29,620 Net income per common share: Basic 1.00 1.01 0.93 0.91 Diluted 0.98 0.98 0.91 0.89 2017 Net interest income $ 58,699 $ 57,233 $ 56,439 $ 54,768 Provision for loan losses 3,323 3,276 1,841 72 Securities transactions 4,412 (22 ) (330 ) — Noninterest income 32,833 29,169 27,983 28,085 Noninterest expense 51,251 50,600 48,953 49,588 Net income 19,497 21,710 23,182 22,050 Net income per common share: Basic 0.61 0.68 0.73 0.70 Diluted 0.59 0.67 0.71 0.68

Description of Business and S_3

Description of Business and Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2019
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Days from origination after which mortgage loan are sold	30 days
Loan upon which a default of principal or interest has existed for a period	90 days
Intangible assets, Estimated useful lives	6 years 8 months 12 days
Accounting Standards Update 2016-01 [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Additional income from changes in equity investments	$ 48,900
Accounting Standards Update 2016-01 [Member] | Other Assets [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Effect of change in accounting principle	5,700,000
Accounting Standards Update 2016-01 [Member] | Equity Securities [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Effect of change in accounting principle	(5,700,000)
Accounting Standards Update 2016-01 [Member] | Retained Earnings [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Effect of change in accounting principle	618,000
Accounting Standards Update 2016-01 [Member] | Accumulated Other Comprehensive Income [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Effect of change in accounting principle	$ 618,000
Accounting Standards Update 2016-02 [Member] | Scenario Forecast [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Effect of change in accounting principle		$ 3,000,000
Core Deposit Intangibles [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Intangible assets, Estimated useful lives	6 years 10 months 24 days
Minimum [Member] | Core Deposit Intangibles [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Intangible assets, Estimated useful lives	7 years
Minimum [Member] | Customer Relationship Intangibles [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Intangible assets, Estimated useful lives	3 years
Maximum [Member] | Core Deposit Intangibles [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Intangible assets, Estimated useful lives	10 years
Maximum [Member] | Customer Relationship Intangibles [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Intangible assets, Estimated useful lives	18 years
Home Equity Lines of Credit [Member] | Maximum [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Loans and finance receivables portfolio percentage	9.00%
First Liens [Member] | Minimum [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Loans and finance receivables portfolio percentage	82.00%
Junior Liens [Member] | Maximum [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Loans and finance receivables portfolio percentage	9.00%

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 ($)CommunityLocation	Jul. 31, 2017shares	Dec. 31, 2017USD ($)	Dec. 31, 2018USD ($)
Business Combination Separately Recognized Transactions [Line Items]
Goodwill					$ 54,042	$ 79,749
Number of additional banking communities | Community			5
Common Stock [Member]
Business Combination Separately Recognized Transactions [Line Items]
Stock split description					On July 31, 2017, the Company completed a two-for-one stock split of the Company’s outstanding shares of common stock.
Stock split conversion ratio				2
Stock payable in form of dividend, payable date				Jul. 31, 2017
Stock payable in form of dividend, record date				Jul. 17, 2017
Additional shares received by stockholders for each share held | shares				1
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 period		2 years
Renovations cost		$ 60,000
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

Cash Due from Banks Interest-Be

Cash Due from Banks Interest-Bearing Deposits and Federal Funds Sold - Summary of Average Amount of Required Reserves (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Average Amount Of Required Reserves [Abstract]
Vault cash and funds on deposit with the Federal Reserve Bank	$ 1,299,872	$ 1,639,058
Average required Reserves	$ 45,195	$ 44,485

Securities - Summary of Amortiz

Securities - Summary of Amortized Cost and Estimated Fair Values of Debt Securities Held for Investment (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 1,428	$ 2,292
Gross Unrealized Gains	5	13
Gross Unrealized Losses		(2)
Estimated Fair Value	1,433	2,303
Mortgage Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	133	187
Gross Unrealized Gains	5	10
Estimated Fair Value	138	197
States and Political Subdivisions [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	795	1,605
Gross Unrealized Gains		3
Gross Unrealized Losses		(2)
Estimated Fair Value	795	1,606
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	Dec. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 773,574	$ 464,298
Gross Unrealized Gains	1,499	840
Gross Unrealized Losses	(4,369)	(3,139)
Estimated Fair Value	770,704	461,999
U.S. Treasuries [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	699,882	314,905
Gross Unrealized Gains	1,108
Gross Unrealized Losses	(3,524)	(2,103)
Estimated Fair Value	697,466	312,802
U.S. Federal Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	30,079	89,098
Gross Unrealized Gains		82
Gross Unrealized Losses	(160)	(329)
Estimated Fair Value	29,919	88,851
Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	16,367	18,358
Gross Unrealized Gains	114	204
Gross Unrealized Losses	(573)	(586)
Estimated Fair Value	15,908	17,976
States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	27,246	41,937
Gross Unrealized Gains	277	554
Gross Unrealized Losses	(112)	(121)
Estimated Fair Value	$ 27,411	$ 42,370

Securities - Maturity of Debt S

Securities - Maturity of Debt Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Held for Investment, Contractual maturity of debt securities, Amortized Cost
Amortized cost, Within one year	$ 495	$ 1,036
Amortized cost, After one year but within five years	369	623
Amortized cost, After five years but within ten years	562	625
Amortized cost, After ten years	2	8
Amortized Cost	1,428	2,292
Available for sale, Contractual maturity of debt securities, Amortized Cost
Amortized Cost, Within one year	411,256	113,225
Amortized Cost, After one year but within five years	313,416	289,038
Amortized Cost, After five years but within ten years	7,524	6,222
Amortized Cost, After ten years	41,378	55,813
Amortized Cost	773,574	464,298
Held for Investment, Contractual maturity of debt securities, Estimated Fair Value
Estimated Fair Value, Within one year	495	1,034
Estimated Fair Value, After one year but within five years	370	627
Estimated Fair Value, After five years but within ten years	565	633
Estimated Fair Value, After ten years	3	9
Estimated Fair Value	1,433	2,303
Available for sale, Contractual maturity of debt securities, Estimated Fair Value
Estimated Fair Value, Within one year	410,327	112,974
Estimated Fair Value, After one year but within five years	311,924	287,058
Estimated Fair Value, After five years but within ten years	7,685	6,500
Estimated Fair Value, After ten years	40,768	55,467
Total debt securities	$ 770,704	$ 461,999

Securities - Proceeds from Sale

Securities - Proceeds from Sales and Realized Securities Losses, on Available for Sale Debt Securities (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
Available For Sale Securities Gross Realized Gain Loss [Abstract]
Proceeds	$ 31,285
Gross losses realized	$ 109

Securities - Company's Book Val

Securities - Company's Book Value of Pledged Debt Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Pledged Financial Instruments Not Separately Reported Securities Pledged By Type Of Security [Abstract]
Book value of pledged securities	$ 472,053	$ 440,069

Securities - Summary of Debt Se

Securities - Summary of Debt Securities with Unrealized Losses, Segregated by Duration of Unrealized Loss (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Available for Sale
Available-for-sale Securities, Less than 12 Months, Fair Value	$ 299,737	$ 308,102
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	100	1,775
Available-for-sale Securities, 12 Months or Longer, Fair Value	313,645	103,780
Available-for-sale Securities, 12 Months or Longer, Unrealized Losses	4,269	1,364
Available-for-sale Securities, Fair Value, Total	613,382	411,882
Available-for-sale Securities, Unrealized Losses, Total	4,369	3,139
Held for Investment
Held-to-maturity Securities, Less than 12 Months, Fair Value		65
Held-to-maturity Securities, 12 Months or Longer, Fair Value	4	485
Held-to-maturity Securities, 12 Months or Longer, Unrealized Losses		2
Held-to-maturity Securities, Fair Value, Total	4	550
Held-to-maturity Securities, Unrealized Losses, Total		2
U.S. Treasuries [Member]
Available for Sale
Available-for-sale Securities, Less than 12 Months, Fair Value	296,438	283,302
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	90	1,653
Available-for-sale Securities, 12 Months or Longer, Fair Value	261,639	29,500
Available-for-sale Securities, 12 Months or Longer, Unrealized Losses	3,434	450
Available-for-sale Securities, Fair Value, Total	558,077	312,802
Available-for-sale Securities, Unrealized Losses, Total	3,524	2,103
U.S. Federal Agencies [Member]
Available for Sale
Available-for-sale Securities, Less than 12 Months, Fair Value	1,705	3,499
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	7	8
Available-for-sale Securities, 12 Months or Longer, Fair Value	27,035	59,220
Available-for-sale Securities, 12 Months or Longer, Unrealized Losses	153	321
Available-for-sale Securities, Fair Value, Total	28,740	62,719
Available-for-sale Securities, Unrealized Losses, Total	160	329
Mortgage Backed Securities [Member]
Available for Sale
Available-for-sale Securities, Less than 12 Months, Fair Value	1	1
Available-for-sale Securities, 12 Months or Longer, Fair Value	13,444	14,475
Available-for-sale Securities, 12 Months or Longer, Unrealized Losses	573	586
Available-for-sale Securities, Fair Value, Total	13,445	14,476
Available-for-sale Securities, Unrealized Losses, Total	573	586
Held for Investment
Held-to-maturity Securities, 12 Months or Longer, Fair Value	4	7
Held-to-maturity Securities, Fair Value, Total	4	7
States and Political Subdivisions [Member]
Available for Sale
Available-for-sale Securities, Less than 12 Months, Fair Value	1,593	21,300
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	3	114
Available-for-sale Securities, 12 Months or Longer, Fair Value	11,527	585
Available-for-sale Securities, 12 Months or Longer, Unrealized Losses	109	7
Available-for-sale Securities, Fair Value, Total	13,120	21,885
Available-for-sale Securities, Unrealized Losses, Total	$ 112	121
Held for Investment
Held-to-maturity Securities, Less than 12 Months, Fair Value		65
Held-to-maturity Securities, 12 Months or Longer, Fair Value		478
Held-to-maturity Securities, 12 Months or Longer, Unrealized Losses		2
Held-to-maturity Securities, Fair Value, Total		543
Held-to-maturity Securities, Unrealized Losses, Total		$ 2

Loans and Allowance for Loan _3

Loans and Allowance for Loan Losses - Schedule of Loans Outstanding by Category (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 4,975,976	$ 4,721,995
Percent	100.00%	100.00%
Taxable [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 76,211	$ 73,827
Percent	1.53%	1.56%
Tax-exempt [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 48,415	$ 48,626
Percent	0.97%	1.03%
Commercial and Financial [Member] | Commercial and Industrial [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 1,032,787	$ 995,207
Percent	20.76%	21.08%
Commercial and Financial [Member] | Oil & Gas Production And Equipment [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 94,729	$ 95,574
Percent	1.90%	2.02%
Commercial and Financial [Member] | Agriculture [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 136,313	$ 141,249
Percent	2.74%	2.99%
Real Estate [Member] | Construction [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 451,224	$ 437,277
Percent	9.07%	9.26%
Real Estate [Member] | Farmland [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 219,241	$ 195,162
Percent	4.41%	4.13%
Real Estate [Member] | One to Four Family Residences [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 979,170	$ 875,766
Percent	19.68%	18.55%
Real Estate [Member] | Multifamily Residential Properties [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 65,949	$ 46,030
Percent	1.33%	0.98%
Real Estate [Member] | Commercial [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 1,506,937	$ 1,487,927
Percent	30.28%	31.51%
Consumer [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 328,069	$ 284,373
Percent	6.59%	6.02%
Other (Not Classified Above) [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 36,931	$ 40,977
Percent	0.74%	0.87%

Loans and Allowance for Loan _4

Loans and Allowance for Loan Losses - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 4,975,976,000	$ 4,721,995,000
Percentage of loans secured by real estate	65.00%
Interest income that would have been recognized	$ 2,300,000	1,800,000	$ 2,000,000
Interest income recognized on impaired loans	0	2,300,000
Commercial and Industrial [Member] | Ancillary Services [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 60,000,000	$ 81,000,000

Loans and Allowance for Loan _5

Loans and Allowance for Loan Losses - Summary of Nonperforming and Restructured Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Summary Of Nonperforming And Restructured Assets [Abstract]
Past due 90 days or more and still accruing	$ 1,916	$ 2,893
Nonaccrual	22,603	31,943
Restructured	13,188	4,720
Total nonperforming and restructured loans	37,707	39,556
Other real estate owned and repossessed assets	6,873	4,424
Total nonperforming and restructured assets	$ 44,580	$ 43,980

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	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans, Total	$ 22,603	$ 31,943
Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans, Total	838	1,108
Real Estate [Member] | Non-residential Real Estate Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans, Total	187	9,809
Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans, Total	954	781
Real Estate [Member] | Residential Real Estate All Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans, Total	5,488	3,980
Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans, Total	5,682	7,785
Consumer Non-real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans, Total	437	250
Other Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans, Total	490	5,596
Acquired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans, Total	$ 8,527	$ 2,634

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	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	$ 38,271	$ 28,719
Current Loans	4,937,705	4,693,276
Total Loans	4,975,976	4,721,995
Accruing Loans 90 Days or More Past Due	1,916	2,893
30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	23,235	13,407
60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	4,881	3,162
90 Days and Greater [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	10,155	12,150
Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	5,967	2,043
Current Loans	620,654	639,575
Total Loans	626,621	641,618
Accruing Loans 90 Days or More Past Due		84
Real Estate [Member] | Non-residential Real Estate Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	2,918	5,288
Current Loans	1,143,210	1,121,303
Total Loans	1,146,128	1,126,591
Accruing Loans 90 Days or More Past Due		432
Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	3,794	3,591
Current Loans	324,908	326,743
Total Loans	328,702	330,334
Accruing Loans 90 Days or More Past Due	430	584
Real Estate [Member] | Residential Real Estate All Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	4,819	3,865
Current Loans	822,685	781,790
Total Loans	827,504	785,655
Accruing Loans 90 Days or More Past Due	612	973
Real Estate [Member] | 30 to 59 Days Past Due [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	5,114	998
Real Estate [Member] | 30 to 59 Days Past Due [Member] | Non-residential Real Estate Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	2,772	2,905
Real Estate [Member] | 30 to 59 Days Past Due [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	2,448	2,211
Real Estate [Member] | 30 to 59 Days Past Due [Member] | Residential Real Estate All Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	1,728	1,739
Real Estate [Member] | 60 to 89 Days Past Due [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	810	68
Real Estate [Member] | 60 to 89 Days Past Due [Member] | Non-residential Real Estate Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	32	271
Real Estate [Member] | 60 to 89 Days Past Due [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	653	403
Real Estate [Member] | 60 to 89 Days Past Due [Member] | Residential Real Estate All Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	292	749
Real Estate [Member] | 90 Days and Greater [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	43	977
Real Estate [Member] | 90 Days and Greater [Member] | Non-residential Real Estate Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	114	2,112
Real Estate [Member] | 90 Days and Greater [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	693	977
Real Estate [Member] | 90 Days and Greater [Member] | Residential Real Estate All Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	2,799	1,377
Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	5,155	4,701
Current Loans	1,278,499	1,279,704
Total Loans	1,283,654	1,284,405
Accruing Loans 90 Days or More Past Due	282	403
Commercial and Financial [Member] | 30 to 59 Days Past Due [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	3,620	2,210
Commercial and Financial [Member] | 60 to 89 Days Past Due [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	702	706
Commercial and Financial [Member] | 90 Days and Greater [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	833	1,785
Consumer Non-real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	3,115	3,048
Current Loans	323,747	285,872
Total Loans	326,862	288,920
Accruing Loans 90 Days or More Past Due	325	194
Consumer Non-real Estate [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	1,991	2,085
Consumer Non-real Estate [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	565	670
Consumer Non-real Estate [Member] | 90 Days and Greater [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	559	293
Other Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	658	4,525
Current Loans	141,251	139,920
Total Loans	141,909	144,445
Other Loans [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	322	506
Other Loans [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	158	103
Other Loans [Member] | 90 Days and Greater [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	178	3,916
Acquired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	11,845	1,658
Current Loans	282,751	118,369
Total Loans	294,596	120,027
Accruing Loans 90 Days or More Past Due	267	223
Acquired Loans [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	5,240	753
Acquired Loans [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	1,669	192
Acquired Loans [Member] | 90 Days and Greater [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due Loans	$ 4,936	$ 713

Loans and Allowance for Loan _8

Loans and Allowance for Loan Losses - Impaired Loans Segregated by Class of Loans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	$ 50,032	$ 49,391
Recorded Investment with Allowance	38,257	39,688
Related Allowance	3,861	5,647
Average Recorded Investment	47,117	35,181
Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	7,126	2,011
Recorded Investment with Allowance	6,933	1,945
Related Allowance	202	141
Average Recorded Investment	7,739	1,858
Real Estate [Member] | Non-residential Real Estate Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	949	10,323
Recorded Investment with Allowance	757	10,240
Related Allowance	50	496
Average Recorded Investment	6,057	3,975
Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	1,789	1,745
Recorded Investment with Allowance	1,545	1,542
Related Allowance	127	146
Average Recorded Investment	1,650	1,440
Real Estate [Member] | Residential Real Estate All Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	7,177	5,837
Recorded Investment with Allowance	6,862	5,549
Related Allowance	2,433	2,135
Average Recorded Investment	7,154	5,258
Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	18,507	18,101
Recorded Investment with Allowance	10,977	11,158
Related Allowance	881	2,412
Average Recorded Investment	12,140	11,131
Consumer Non-real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	928	545
Recorded Investment with Allowance	829	514
Related Allowance	131	127
Average Recorded Investment	846	541
Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	710	6,092
Recorded Investment with Allowance	490	5,595
Related Allowance	35	178
Average Recorded Investment	481	7,439
Acquired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	12,846	4,737
Recorded Investment with Allowance	9,864	3,145
Related Allowance	2	12
Average Recorded Investment	$ 11,050	$ 3,539

Loans and Allowance for Loan _9

Loans and Allowance for Loan Losses - Internal Loan Grading by Class of Loans (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 4,975,976	$ 4,721,995
Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	626,621	641,618
Real Estate [Member] | Non-residential Real Estate Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	1,146,128	1,126,591
Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	328,702	330,334
Real Estate [Member] | Residential Real Estate All Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	827,504	785,655
Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	1,283,654	1,284,405
Consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	326,862	288,920
Other Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	141,909	144,445
Acquired Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	294,596	120,027
Grade 1 [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	3,902,046	3,851,837
Grade 1 [Member] | Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	451,059	520,641
Grade 1 [Member] | Real Estate [Member] | Non-residential Real Estate Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	932,454	931,295
Grade 1 [Member] | Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	279,870	289,200
Grade 1 [Member] | Real Estate [Member] | Residential Real Estate All Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	644,217	621,401
Grade 1 [Member] | Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	1,000,089	1,018,172
Grade 1 [Member] | Consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	302,217	268,826
Grade 1 [Member] | Other Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	136,132	136,617
Grade 1 [Member] | Acquired Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	156,008	65,685
Grade 2 [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	948,216	758,681
Grade 2 [Member] | Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	157,715	105,696
Grade 2 [Member] | Real Estate [Member] | Non-residential Real Estate Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	188,341	178,282
Grade 2 [Member] | Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	39,806	33,033
Grade 2 [Member] | Real Estate [Member] | Residential Real Estate All Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	162,003	149,201
Grade 2 [Member] | Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	264,134	234,884
Grade 2 [Member] | Consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	21,600	17,499
Grade 2 [Member] | Other Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	5,542	5,668
Grade 2 [Member] | Acquired Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	109,075	34,418
Grade 3 [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	103,111	88,588
Grade 3 [Member] | Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	16,949	13,852
Grade 3 [Member] | Real Estate [Member] | Non-residential Real Estate Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	25,146	14,290
Grade 3 [Member] | Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	7,401	6,352
Grade 3 [Member] | Real Estate [Member] | Residential Real Estate All Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	15,232	9,418
Grade 3 [Member] | Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	15,128	24,322
Grade 3 [Member] | Consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	2,255	2,038
Grade 3 [Member] | Other Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	116	1,203
Grade 3 [Member] | Acquired Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	20,884	17,113
Grade 4 [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	22,258	22,859
Grade 4 [Member] | Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	898	1,429
Grade 4 [Member] | Real Estate [Member] | Non-residential Real Estate Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	187	2,724
Grade 4 [Member] | Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	1,625	1,749
Grade 4 [Member] | Real Estate [Member] | Residential Real Estate All Other [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	6,052	5,635
Grade 4 [Member] | Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	4,303	6,997
Grade 4 [Member] | Consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	790	557
Grade 4 [Member] | Other Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	119	957
Grade 4 [Member] | Acquired Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	8,284	2,811
Grade 5 [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	345	30
Grade 5 [Member] | Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans		$ 30
Grade 5 [Member] | Acquired Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 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								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of period				$ 51,666				$ 48,693	$ 51,666	$ 48,693
Charge- offs									(5,003)	(6,965)
Recoveries									924	1,426
Net charge- offs									(4,079)	(5,539)
Provisions charged to operations	$ 1,516	$ 747	$ 1,225	314	$ 3,323	$ 3,276	$ 1,841	72	3,802	8,512	$ 11,519
Balance at end of period	51,389				51,666				51,389	51,666	48,693
Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of period				6,195				5,602	6,195	5,602
Charge- offs									(282)	(74)
Recoveries									17	6
Net charge- offs									(265)	(68)
Provisions charged to operations									398	661
Balance at end of period	6,328				6,195				6,328	6,195	5,602
Real Estate [Member] | Non-residential Real Estate Other [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of period				10,519				10,793	10,519	10,793
Charge- offs									(93)	(47)
Recoveries									41	16
Net charge- offs									(52)	(31)
Provisions charged to operations									560	(243)
Balance at end of period	11,027				10,519				11,027	10,519	10,793
Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of period				3,226				3,129	3,226	3,129
Charge- offs									(174)	(373)
Recoveries									26	25
Net charge- offs									(148)	(348)
Provisions charged to operations									183	445
Balance at end of period	3,261				3,226				3,261	3,226	3,129
Real Estate [Member] | Residential Real Estate All Other [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of period				9,672				8,622	9,672	8,622
Charge- offs									(395)	(330)
Recoveries									106	66
Net charge- offs									(289)	(264)
Provisions charged to operations									1,290	1,314
Balance at end of period	10,673				9,672				10,673	9,672	8,622
Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of period				15,334				12,421	15,334	12,421
Charge- offs									(2,257)	(1,344)
Recoveries									92	1,033
Net charge- offs									(2,165)	(311)
Provisions charged to operations									(18)	3,224
Balance at end of period	13,151				15,334				13,151	15,334	12,421
Consumer Non-real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of period				2,793				2,804	2,793	2,804
Charge- offs									(1,066)	(913)
Recoveries									245	180
Net charge- offs									(821)	(733)
Provisions charged to operations									1,093	722
Balance at end of period	3,065				2,793				3,065	2,793	2,804
Other Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of period				2,481				4,045	2,481	4,045
Charge- offs									(16)	(3,727)
Recoveries									361	23
Net charge- offs									345	(3,704)
Provisions charged to operations									(403)	2,140
Balance at end of period	2,423				2,481				2,423	2,481	4,045
Acquired Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of period				$ 1,446				$ 1,277	1,446	1,277
Charge- offs									(720)	(157)
Recoveries									36	77
Net charge- offs									(684)	(80)
Provisions charged to operations									699	249
Balance at end of period	$ 1,461				$ 1,446				$ 1,461	$ 1,446	$ 1,277

Loans and Allowance for Loan_11

Loans and Allowance for Loan Losses - Allowance for Loan Losses Outstanding by Impairment Methodology (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	$ 8,259	$ 9,876
Collectively evaluated for impairment	43,130	41,790
Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	669	656
Collectively evaluated for impairment	5,659	5,539
Real Estate [Member] | Non-residential Real Estate Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	1,119	751
Collectively evaluated for impairment	9,908	9,768
Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	505	483
Collectively evaluated for impairment	2,756	2,743
Real Estate [Member] | Residential Real Estate All Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	3,413	2,761
Collectively evaluated for impairment	7,260	6,911
Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	2,114	4,651
Collectively evaluated for impairment	11,037	10,683
Consumer Non-real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	374	429
Collectively evaluated for impairment	2,691	2,364
Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	65	133
Collectively evaluated for impairment	2,358	2,348
Acquired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment		12
Collectively evaluated for impairment	$ 1,461	$ 1,434

Loans and Allowance for Loan_12

Loans and Allowance for Loan Losses - Loans Outstanding by Impairment Methodology (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	$ 118,356	$ 104,623
Collectively evaluated for impairment	4,850,240	4,611,915
Loans Acquired with Deteriorated Credit Quality [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans acquired with deteriorated credit quality	7,380	5,457
Real Estate [Member] | Non-residential Real Estate Owner Occupied [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	17,846	15,281
Collectively evaluated for impairment	608,775	626,337
Real Estate [Member] | Non-residential Real Estate Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	25,333	17,013
Collectively evaluated for impairment	1,120,795	1,109,578
Real Estate [Member] | Residential Real Estate Permanent Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	9,026	8,100
Collectively evaluated for impairment	319,676	322,234
Real Estate [Member] | Residential Real Estate All Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	21,285	15,052
Collectively evaluated for impairment	806,219	770,603
Commercial and Financial [Member] | Non-consumer Non-real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	19,432	31,349
Collectively evaluated for impairment	1,264,222	1,253,056
Consumer Non-real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	3,093	2,600
Collectively evaluated for impairment	323,769	286,320
Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	209	764
Collectively evaluated for impairment	141,700	143,681
Acquired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Individually evaluated for impairment	22,132	14,464
Collectively evaluated for impairment	265,084	100,106
Acquired Loans [Member] | Loans Acquired with Deteriorated Credit Quality [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans acquired with deteriorated credit quality	$ 7,380	$ 5,457

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 Repossesed Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Noncash Investing And Financing Items [Abstract]
Other real estate owned	$ 5,437	$ 2,889	$ 2,553
Repossessed assets	1,122	1,242	1,402
Total	$ 6,559	$ 4,131	$ 3,955

Loans and Allowance for Loan_14

Loans and Allowance for Loan Losses - Related Party Loans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Receivables [Abstract]
Balance Beginning of the Period	$ 24,001	$ 27,486	$ 37,577
Additions	7,986	7,350	16,133
Collections/ Terminations	(12,096)	(10,835)	(26,224)
Balance End of the Period	$ 19,891	$ 24,001	$ 27,486

Premises and Equipment, Net a_3

Premises and Equipment, Net and Other Assets - Summary of premises and equipment by classification (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Property Plant And Equipment [Line Items]
Accumulated depreciation	$ (117,392)	$ (115,711)
Premises and equipment, net	174,362	134,088
Building [Member]
Property Plant And Equipment [Line Items]
Premises and Equipment, gross	$ 181,182	145,051
Building [Member] | Minimum [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Lives	10 years
Building [Member] | Maximum [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Lives	40 years
Furniture Fixtures And Equipment [Member]
Property Plant And Equipment [Line Items]
Premises and Equipment, gross	$ 75,138	69,915
Furniture Fixtures And Equipment [Member] | Minimum [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Lives	3 years
Furniture Fixtures And Equipment [Member] | Maximum [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Lives	15 years
Land [Member]
Property Plant And Equipment [Line Items]
Premises and Equipment, gross	$ 35,434	$ 34,833

Premises and Equipment, Net a_4

Premises and Equipment, Net and Other Assets - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property Plant And Equipment [Abstract]
Percentage of equity investment	50.00%
Low income housing tax credit investments	$ 18.5	$ 16.9
Tax credits and other tax benefits recognized from LIHTC investments	5.4	4.4	$ 4.2
Amortization expense resulting from LIHTC investments	4.4	$ 3.5	$ 2.9
Unfunded commitment on investments	$ 17.3

Intangible Assets and Goodwil_2

Intangible Assets and Goodwill - Summary of Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 32,003	$ 23,585
Accumulated Amortization	(15,533)	(12,503)
Net Carrying Amount	16,470	11,082
Core Deposit Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	25,907	17,447
Accumulated Amortization	(11,113)	(8,451)
Net Carrying Amount	14,794	8,996
Customer Relationship Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	5,699	5,699
Accumulated Amortization	(4,115)	(3,767)
Net Carrying Amount	1,584	1,932
Mortgage Servicing Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	397	439
Accumulated Amortization	(305)	(285)
Net Carrying Amount	$ 92	$ 154

Intangible Assets and Goodwil_3

Intangible Assets and Goodwill - Estimated Amortization of Intangible Assets (Detail) $ in Thousands	Dec. 31, 2018USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
2,019	$ 3,056
2,020	2,975
2,021	2,246
2,022	1,935
2,023	$ 1,811

Intangible Assets and Goodwil_4

Intangible Assets and Goodwill - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Weighted-average life	6 years 8 months 12 days
Customer Related Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted-average life	5 years 1 month 6 days
Core Deposit Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted-average life	6 years 10 months 24 days
Mortgage Servicing Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted-average life	2 years

Intangible Assets and Goodwil_5

Intangible Assets and Goodwill - Summary of Goodwill by Business Segment (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
Goodwill [Line Items]
Balance at beginning of period	$ 54,042
Acquisitions	25,707
Balance at end of period	79,749
Metropolitan Banks [Member]
Goodwill [Line Items]
Balance at beginning of period	8,078
Acquisitions	5,689
Balance at end of period	13,767
Community Banks [Member]
Goodwill [Line Items]
Balance at beginning of period	39,876
Acquisitions	20,018
Balance at end of period	59,894
Other Financial Services [Member]
Goodwill [Line Items]
Balance at beginning of period	5,464
Balance at end of period	5,464
Executive, Operations & Support [Member]
Goodwill [Line Items]
Balance at beginning of period	624
Balance at end of period	$ 624

Time Deposits - Summary of Sche

Time Deposits - Summary of Scheduled Maturities of all Time Deposits (Detail) $ in Thousands	Dec. 31, 2018USD ($)
Deposits [Abstract]
2,019	$ 458,378
2,020	122,648
2,021	53,661
2,022	39,979
2,023	31,276
Thereafter	4
Total	$ 705,946

Time Deposits - Summary of Larg

Time Deposits - Summary of Large time Deposits and time Deposits Meet or Exceed Current FDIC Insurance Limit for Periods Presented (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deposits [Abstract]
Time deposits of $100,000 or more	$ 349,918	$ 319,811
Time deposits of $250,000 or more	$ 132,957	$ 122,391

Short-Term Borrowings - Summary

Short-Term Borrowings - Summary of Short-Term Borrowings (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Short-term Debt [Line Items]
Short-term borrowings	$ 1,675	$ 900
Weighted average interest rate	1.84%	0.97%
Federal Funds Purchased [Member]
Short-term Debt [Line Items]
Short-term borrowings	$ 1,675	$ 900
Short-term Debt [Member]
Short-term Debt [Line Items]
End of period interest rate	2.30%	1.38%

Long-Term Borrowings - Addition

Long-Term Borrowings - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2018USD ($)
Debt Instrument [Line Items]
Maximum drawing capacity	$ 619,100,000
FHLB stock holdings	553,400
Advances outstanding	0
Residential Mortgage [Member]
Debt Instrument [Line Items]
Line of credit assets pledged as collateral	775,300,000
Revolving Line of Credit Member]
Debt Instrument [Line Items]
Maximum drawing capacity	10,000,000
Advances outstanding	$ 0
Description of variable interest rate	prime rate minus 25 basis points
Line of credit maturity year	2,020

Junior Subordinated Debentures

Junior Subordinated Debentures - Additional Information (Detail) - USD ($)	Oct. 08, 2015	Mar. 31, 2004	Feb. 29, 2004	Dec. 31, 2018	Dec. 31, 2017
Junior Subordinated Debentures [Line Items]
Junior subordinated notes assumed				$ 26,804,000	$ 31,959,000
BancFirst Capital Trust Two [Member] | Subordinated Debentures Subject to Mandatory Redemption [Member]
Junior Subordinated Debentures [Line Items]
Interest rate of securities				7.20%
Frequency of payment				Payable January 15, April 15, July 15 and October 15 of each year.
Junior subordinated notes assumed				$ 26,800,000
Debt instrument maturity date				Mar. 31, 2034
BancFirst Capital Trust Two [Member] | Cumulative Preferred Stock [Member]
Junior Subordinated Debentures [Line Items]
Issue of securities		$ 1,000,000	$ 25,000,000
Cumulative trust preferred securities interest rate				7.20%
CSB Bancshares Statutory Trust I [Member]
Junior Subordinated Debentures [Line Items]
Business combination, acquisition of capital securities	$ 5,000,000
Business combination, acquisition of common securities	155,000
CSB Bancshares Statutory Trust I [Member] | Subordinated Deferrable Interest Debentures [Member]
Junior Subordinated Debentures [Line Items]
Frequency of payment				Payable March 15, June 15, September 15 and December 15 of each year
Junior subordinated notes assumed	$ 5,200,000
Debt instrument maturity date	Sep. 15, 2036
CSB Bancshares Statutory Trust I [Member] | Subordinated Deferrable Interest Debentures [Member] | LIBOR [Member]
Junior Subordinated Debentures [Line Items]
Debt instrument, Basis point rate	1.82%

Income Taxes - Components of th

Income Taxes - Components of the Company's Income Tax Expense (Benefit) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current taxes:
Federal	$ 23,700	$ 39,569	$ 34,003
State	7,083	5,914	5,308
Deferred taxes	3,155	4,383	(2,048)
Total income taxes	$ 33,938	$ 49,866	$ 37,263

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Taxes [Line Items]
Securities transactions income tax expense (benefit)	$ 10,000	$ 1.4	$ (21,000)
Change in income tax expense (benefit) due to write down of net deferred tax asset resulting from federal tax rate change		$ 4,300,000
Federal tax rate, percentage	21.00%	35.00%	35.00%
Recognition of interest and penalties related to unrecognized tax benefits	$ 0	$ 0	$ 0
Earliest Tax Year [Member]
Income Taxes [Line Items]
Year under examination	2,016	2,013
Latest Tax Year [Member]
Income Taxes [Line Items]
Year under examination	2,018	2,015

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Tax Expense at the Federal Statutory Tax Rate (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Tax expense at the federal statutory tax rate	$ 33,546	$ 47,708	$ 37,778
Increase (decrease) in tax expense from:
Tax-exempt income, net	(510)	(829)	(756)
Modified endowment life contracts	(558)	(921)	(852)
Share based compensation excess tax benefit	(917)	(2,354)
State tax expense, net of federal tax benefit	5,595	3,840	3,250
Write-down of net deferred tax asset		4,331
Utilization of tax credits:
New markets tax credits	(1,422)	(1,151)	(1,254)
Low-income housing tax credits, net of amortization	(1,273)	(1,589)	(1,424)
Other tax credits			(319)
Other, net	(523)	831	840
Total income taxes	$ 33,938	$ 49,866	$ 37,263

Income Taxes - Summary of Net D

Income Taxes - Summary of Net Deferred Tax Asset Reported in Other Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Provision for loan losses	$ 13,089	$ 13,123
Unrealized net losses on securities	731	739
Write-downs of other real estate owned	462	473
Deferred compensation	2,209	2,113
Stock-based compensation	1,448	1,351
Investments in partnership interests	4,274	3,758
Other	963	275
Gross deferred tax assets	23,176	21,832
Premium on securities of banks acquired	(185)	(219)
Intangibles	(5,376)	(3,359)
Basis difference related to tax credits	(2,560)	(2,713)
Depreciation	(8,484)	(4,563)
Leveraged lease		(821)
Prepaid expense deducted	(1,178)	(887)
Other	(181)	(180)
Gross deferred tax liabilities	(17,964)	(12,742)
Net deferred tax asset	$ 5,212	$ 9,090

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
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	282,970
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	2,025
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	2,022
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	3,891	9,918

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Activity Under Stock Option Plan (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Outstanding at beginning period - Options	1,273,625	1,414,900
Options granted	72,000	121,500
Options exercised	(123,925)	(262,775)
Options canceled, forfeited, or expired	(5,000)
Outstanding at ending period - Options	1,216,700	1,273,625
Exercisable at ending period - Options	601,700	566,625
Outstanding at beginning period - Wgtd. Avg. Exercise Price	$ 25.90	$ 22.46
Options granted - Wgtd. Avg. Exercise Price	56.47	48.26
Options exercised - Wgtd. Avg. Exercise Price	17.42	17.73
Options cancelled, forfeited, or expired - Wgtd. Avg. Exercise Price	48.02
Outstanding at ending period - Wgtd. Avg. Exercise Price	28.48	25.90
Exercisable at ending period - Wgtd. Avg. Exercise Price	$ 21.53	$ 20.07
Outstanding at ending period - Wgtd. Avg. Remaining Contractual Term, years	9 years 6 months 10 days	9 years 8 months 23 days
Exercisable at ending period - Wgtd. Avg. Remaining Contractual Term, years	7 years 1 month 13 days	6 years 11 months 1 day
Outstanding at ending period - Aggregate Intrinsic Value	$ 26,066	$ 32,165
Exercisable at ending period - Aggregate Intrinsic Value	$ 17,070	$ 17,611

Stock-Based Compensation - Opti

Stock-Based Compensation - Options Exercised Under Stock Option Plan (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award Options Additional Disclosures [Abstract]
Total intrinsic value of options exercised	$ 4,810	$ 8,389	$ 12,230
Cash received from options exercised	2,159	4,660	9,720
Tax benefit realized from options exercised	$ 1,225	$ 3,245	$ 4,731

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock-Based Employee Compensation Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Labor And Related Expense [Abstract]
Stock-based compensation expense	$ 1,352	$ 1,180	$ 1,636
Tax benefit	345	301	633
Stock-based compensation expense, net of tax	$ 1,007	$ 879	$ 1,003

Stock-Based Compensation - Unea

Stock-Based Compensation - Unearned Stock-based Compensation Expense (Detail) $ in Thousands	Dec. 31, 2018USD ($)
Share Based Compensation [Abstract]
Unearned stock-based compensation expense	$ 3,319

Stock-Based Compensation - Assu

Stock-Based Compensation - Assumptions Used for Computing Stock-Based Compensation Expense (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
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	$ 14.71	$ 11.87	$ 5.96
Risk-free interest rate, minimum	2.55%	2.15%	1.46%
Risk-free interest rate, maximum	3.05%	2.40%	2.02%
Dividend yield	2.00%	2.00%	2.00%
Stock price volatility, minimum	23.05%	22.57%	20.41%
Stock price volatility, maximum	23.95%	24.18%	21.78%
Expected term	10 years	10 years	10 years

Stock - Based Compensation - Su

Stock - Based Compensation - Summary of Accumulated Stock Units (Detail) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Accumulated stock units	143,347	138,768
Average price	$ 24.91	$ 22.84

Retirement Plans - Additional I

Retirement Plans - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2018Plans
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Number of retirement plans	2
Maximum [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Maximum legal limit of employer contribution to plan	3.00%

Retirement Plans - Aggregate Am

Retirement Plans - Aggregate Amounts of Contributions to the 401(k) and ESOP Plans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Contribution Plan Disclosure [Line Items]
Total contributions	$ 6,538	$ 4,874	$ 4,426
401(k) contributions [Member]
Defined Contribution Plan Disclosure [Line Items]
Aggregate amounts of contributions	2,465	2,229	2,074
ESOP contributions [Member]
Defined Contribution Plan Disclosure [Line Items]
Aggregate amounts of contributions	$ 4,073	$ 2,645	$ 2,352

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Authorized Outstanding Preferred and Common Stock (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Class of Stock [Line Items]
Common stock, shares authorized	40,000,000	40,000,000
Common stock, shares outstanding	32,603,926	31,894,563	31,621,870
Common stock, par value	$ 1	$ 1
Common stock dividend payment terms	As declared
Common stock, voting rights	Voting
Senior Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares outstanding	0
Preferred stock, par value	$ 1	$ 1
Preferred stock, dividend payment terms	As declared
Preferred stock, voting rights	Voting
Cumulative Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares authorized	900,000	900,000
Preferred stock, shares outstanding	0
Preferred stock, par value	$ 5	$ 5
Preferred stock, dividend payment terms	As declared
Preferred stock, voting rights	Non-voting

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Jan. 01, 2019	Dec. 31, 2017
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
Subsequent Event [Member]
Stockholders Equity [Line Items]
Available equity of BancFirst for dividend payments to the company		$ 140,300,000
Senior Preferred Stock [Member]
Stockholders Equity [Line Items]
Preferred stock, shares issued	0		0
Preferred stock, shares outstanding	0
Cumulative Preferred Stock [Member]
Stockholders Equity [Line Items]
Preferred stock, shares issued	0		0
Preferred stock, shares outstanding	0
Dividend payable at redemption, per share	$ 5
Cumulative preferred stock dividend rate	10.00%

Stockholders' Equity - Summar_2

Stockholders' Equity - Summary of Shares Repurchased Under Stock Purchase Program (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2016	Dec. 31, 2017
Summary Of Shares Repurchased Under Stock Purchase Program [Abstract]
Number of shares repurchased	151,264	200,000
Average price of shares repurchased	$ 52.32	$ 27.62
Shares remaining to be repurchased	148,736	300,000	300,000

Stockholders' Equity - Required

Stockholders' Equity - Required Capital Amounts and Company's Respective Ratios (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Parent Company [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital Amount	$ 886,190	$ 797,015
Total Capital To Risk Weighted Assets Actual Ratio	16.29%	15.62%
Capital Required For Capital Adequacy Amount	$ 435,208	$ 408,234
Capital Required For Capital Adequacy to Risk Weighted Assets Ratio	8.00%	8.00%
Capital With Capital Conservation Buffer Amount	$ 537,210	$ 472,020
Capital With Capital Conservation To Risk Based Weighted Assets Buffer Ratio	9.875%	9.25%
Common Equity Tier 1 Risk Based Capital Amount	$ 808,801	$ 714,349
Common Equity Tier 1 Risk Based Capital To Risk Weighted Assets Ratio	14.87%	14.00%
Common Equity Tier 1 Risk Based Capital Required For Capital Adequacy Amount	$ 244,804	$ 229,632
Common Equity Tier 1 Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets Ratio	4.50%	4.50%
Common Equity Tier 1 Risk Based Capital With Capital Conservation Buffer Amount	$ 346,806	$ 293,418
Common Equity Tier 1 Risk Based Capital With Capital Conservation Buffer To Risk Weighted Assets Ratio	6.375%	5.75%
Tier 1 Risk Based Capital Amount	$ 834,801	$ 745,349
Tier 1 Risk Based Capital To Risk Weighted Assets Ratio	15.35%	14.61%
Tier 1 Risk Based Capital Required For Capital Adequacy Amount	$ 326,406	$ 306,175
Tier 1 Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets Ratio	6.00%	6.00%
Tier 1 Risk Based Capital With Capital Conservation Buffer Amount	$ 428,408	$ 369,962
Tier 1 Risk Based Capital With Capital Conservation Buffer To Risk Weighted Assets Ratio	7.875%	7.25%
Tier 1 Capital Amount	$ 834,801	$ 745,349
Tier 1 Capital To Average Assets Ratio	11.09%	10.44%
Tier 1 Capital Required For Capital Adequacy Amount	$ 301,116	$ 285,444
Tier 1 Capital Required For Capital Adequacy To Average Assets Ratio	4.00%	4.00%
BancFirst [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital Amount	$ 765,487	$ 714,964
Total Capital To Risk Weighted Assets Actual Ratio	14.09%	14.03%
Capital Required For Capital Adequacy Amount	$ 434,573	$ 407,698
Capital Required For Capital Adequacy to Risk Weighted Assets Ratio	8.00%	8.00%
Capital With Capital Conservation Buffer Amount	$ 536,426	$ 471,401
Capital With Capital Conservation To Risk Based Weighted Assets Buffer Ratio	9.875%	9.25%
Capital Required To Be Well Capitalized Amount	$ 543,216	$ 509,622
Capital Required To Be Well Capitalized To Risk Weighted Assets Ratio	10.00%	10.00%
Common Equity Tier 1 Risk Based Capital Amount	$ 694,098	$ 643,298
Common Equity Tier 1 Risk Based Capital To Risk Weighted Assets Ratio	12.78%	12.62%
Common Equity Tier 1 Risk Based Capital Required For Capital Adequacy Amount	$ 244,447	$ 229,330
Common Equity Tier 1 Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets Ratio	4.50%	4.50%
Common Equity Tier 1 Risk Based Capital With Capital Conservation Buffer Amount	$ 346,300	$ 293,033
Common Equity Tier 1 Risk Based Capital With Capital Conservation Buffer To Risk Weighted Assets Ratio	6.375%	5.75%
Common Equity Tier 1 Risk Based Capital Required To Be Well Capitalized Amount	$ 353,090	$ 331,255
Common Equity Tier 1 Risk Based Capital Required To Be Well Capitalized To Risk Weighted Assets Ratio	6.50%	6.50%
Tier 1 Risk Based Capital Amount	$ 714,098	$ 663,298
Tier 1 Risk Based Capital To Risk Weighted Assets Ratio	13.15%	13.02%
Tier 1 Risk Based Capital Required For Capital Adequacy Amount	$ 325,930	$ 306,773
Tier 1 Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets Ratio	6.00%	6.00%
Tier 1 Risk Based Capital With Capital Conservation Buffer Amount	$ 427,783	$ 369,476
Tier 1 Risk Based Capital With Capital Conservation Buffer To Risk Weighted Assets Ratio	7.875%	7.25%
Tier 1 Risk Based Capital Required To Be Well Capitalized Amount	$ 434,573	$ 407,698
Tier 1 Risk Based Capital Required To Be Well Capitalized To Risk Weighted Assets Ratio	8.00%	8.00%
Tier 1 Capital Amount	$ 714,098	$ 663,298
Tier 1 Capital To Average Assets Ratio	9.49%	9.31%
Tier 1 Capital Required For Capital Adequacy Amount	$ 300,855	$ 285,101
Tier 1 Capital Required For Capital Adequacy To Average Assets Ratio	4.00%	4.00%
Tier 1 Capital Required To Be Well Capitalized Amount	$ 376,069	$ 356,677
Tier 1 Capital Required To Be Well Capitalized To Average Assets Ratio	5.00%	5.00%

Net Income Per Common Share - B

Net Income Per Common Share - Basic and Diluted Net Income Per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share Reconciliation [Abstract]
Income available to common stockholders									$ 125,814	$ 86,439	$ 70,674
Income available to common stockholders plus assumed exercises of stock options									$ 125,814	$ 86,439	$ 70,674
Income available to common stockholders - Shares									32,689,228	31,813,572	31,230,340
Effect of stock options - Shares									741,486	754,533	592,184
Income available to common stockholders plus assumed exercises of stock options - Shares									33,430,714	32,568,105	31,822,524
Income available to common stockholders - Per Share Amount	$ 1	$ 1.01	$ 0.93	$ 0.91	$ 0.61	$ 0.68	$ 0.73	$ 0.70	$ 3.85	$ 2.72	$ 2.27
Income available to common stockholders plus assumed exercises of stock options - Per Share Amount	$ 0.98	$ 0.98	$ 0.91	$ 0.89	$ 0.59	$ 0.67	$ 0.71	$ 0.68	$ 3.76	$ 2.65	$ 2.22

Net Income Per Common Share - A

Net Income Per Common Share - Average Exercise Prices of Options Excluded from Computation of Diluted Net Income Per Common Share (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Abstract]
Shares	92,738	55,337	294,438
Average Exercise Price	$ 53.17	$ 46.86	$ 30.25

Condensed Parent Company Fina_3

Condensed Parent Company Financial Statements - Summary of Balance Sheet of Parent Company (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
ASSETS
Cash	$ 228,431	$ 216,104
Goodwill	79,749	54,042
Total assets	7,574,258	7,253,156	$ 7,018,952
LIABILITIES AND STOCKHOLDERS' EQUITY
Other liabilities	37,495	29,623
Junior subordinated debentures	26,804	31,959
Stockholders’ equity	902,789	775,629	$ 711,094
Total liabilities and stockholders' equity	7,574,258	7,253,156
Parent Company [Member]
ASSETS
Cash	105,089	67,917
Investments in subsidiaries	822,336	737,031
Goodwill	624	624
Dividends receivable	11,058	7,788
Other assets	958	1,401
Total assets	940,065	814,761
LIABILITIES AND STOCKHOLDERS' EQUITY
Other liabilities	10,472	7,173
Junior subordinated debentures	26,804	31,959
Stockholders’ equity	902,789	775,629
Total liabilities and stockholders' equity	$ 940,065	$ 814,761

Condensed Parent Company Fina_4

Condensed Parent Company Financial Statements- Summary of Income Statement of Parent Company (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
OPERATING INCOME
Interest on interest-bearing deposits									$ 30,403	$ 18,077	$ 7,908
OPERATING EXPENSE
Other									39,887	36,136	32,857
Allocated income tax benefit									(33,938)	(49,866)	(37,263)
Amortization of stock-based compensation arrangements of subsidiaries									(1,352)	(1,180)	(1,636)
Net income	$ 32,725	$ 32,883	$ 30,586	$ 29,620	$ 19,497	$ 21,710	$ 23,182	$ 22,050	125,814	86,439	70,674
Parent Company [Member]
OPERATING INCOME
Dividends from subsidiaries									38,326	29,455	28,175
Interest on interest-bearing deposits									1,151	291	160
Other									16	3	3
Total operating income									39,493	29,749	28,338
OPERATING EXPENSE
Interest									2,172	2,122	2,096
Other									698	770	583
Total operating expense									2,870	2,892	2,679
Income before taxes									36,623	26,857	25,659
Allocated income tax benefit									3,093	3,295	1,244
Income before equity in undistributed earnings of subsidiaries									39,716	30,152	26,903
Equity in undistributed earnings of subsidiaries									87,404	57,429	44,172
Amortization of stock-based compensation arrangements of subsidiaries									(1,306)	(1,142)	(401)
Net income									$ 125,814	$ 86,439	$ 70,674

Condensed Parent Company Fina_5

Condensed Parent Company Financial Statements - Summary of Cash Flow of Parent Company (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 32,725	$ 32,883	$ 30,586	$ 29,620	$ 19,497	$ 21,710	$ 23,182	$ 22,050	$ 125,814	$ 86,439	$ 70,674
Adjustments to reconcile to net cash provided by operating activities:
Amortization of stock-based compensation arrangements of subsidiaries									1,352	1,180	1,636
Other, net									(10,063)	(1,173)	(5,500)
INVESTING ACTIVITIES
Other, net									(3,890)	4,038	9,519
FINANCING ACTIVITIES
Common stock acquired									(7,914)		(5,523)
Cash dividends paid									(30,265)	(24,783)	(22,770)
Redemption of Junior Subordinated debentures									(5,155)
Net (decrease)/increase in cash, due from banks and interest-bearing deposits									(333,620)	(92,586)	252,284
Cash, due from banks and interest-bearing deposits at the beginning of the period				1,757,875				1,850,461	1,757,875	1,850,461	1,598,177
Cash, due from banks and interest-bearing deposits at the end of the period	1,424,255				1,757,875				1,424,255	1,757,875	1,850,461
SUPPLEMENTAL DISCLOSURE
Cash paid during the period for interest									41,549	20,563	14,673
Cash received during the period for income taxes, net									27,952	41,058	32,700
Parent Company [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income									125,814	86,439	70,674
Adjustments to reconcile to net cash provided by operating activities:
Equity in undistributed earnings of subsidiaries									(87,404)	(57,429)	(44,172)
Amortization of stock-based compensation arrangements of subsidiaries									1,306	1,142	401
Other, net									(2,621)	569	136
Net cash provided by operating activities									37,095	30,721	27,039
INVESTING ACTIVITIES
Net cash provided by acquisitions									41,347
Payments for investments in subsidiaries										(502)
Other, net									(174)	100
Net cash provided by (used in) investing activities									41,173	(402)
FINANCING ACTIVITIES
Issuance of common stock									2,238	4,844	13,354
Common stock acquired									(7,914)		(5,523)
Cash dividends paid									(30,265)	(24,783)	(22,770)
Redemption of Junior Subordinated debentures									(5,155)
Net cash used for financing activities									(41,096)	(19,939)	(14,939)
Net (decrease)/increase in cash, due from banks and interest-bearing deposits									37,172	10,380	12,100
Cash, due from banks and interest-bearing deposits at the beginning of the period				$ 67,917				$ 57,537	67,917	57,537	45,437
Cash, due from banks and interest-bearing deposits at the end of the period	$ 105,089				$ 67,917				105,089	67,917	57,537
SUPPLEMENTAL DISCLOSURE
Cash paid during the period for interest									2,171	2,122	2,096
Cash received during the period for income taxes, net									$ 3,647	$ 4,643	$ 5,031

Commitments and Contingent Li_3

Commitments and Contingent Liabilities - Summary of Financial Instruments with Off-Balance-Sheet Risks (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Loan commitments	$ 1,232,996	$ 1,050,686
Stand-by letters of credit	$ 56,096	$ 57,074

Commitments and Contingent Li_4

Commitments and Contingent Liabilities - Summary of Future Minimum Lease Payments Under Operating Leases (Detail) $ in Thousands	Dec. 31, 2018USD ($)
Operating Leases Future Minimum Payments Due [Abstract]
2,019	$ 1,049
2,020	789
2,021	569
2,022	369
2,023	60
Later years	499
Total	$ 3,335

Commitments and Contingent Li_5

Commitments and Contingent Liabilities - Summary of Rental Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Leases Rent Expense [Abstract]
Rent expense on all property and equipment rented	$ 1,857	$ 1,597	$ 1,524

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value of Financial Assets and Liabilities Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	$ 770,704	$ 461,999
Equity securities	7,521	5,704
Derivative assets	252	295
Derivative liabilities	238	261
U.S. Treasuries [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	697,466	312,802
U.S. Federal Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	29,919	88,851
Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	15,908	17,976
States and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	27,411	42,370
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	697,466	312,802
Level 2 Inputs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	252	295
Derivative liabilities	238	261
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	29,919	88,851
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	2,465	3,509
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	27,411	42,370
Level 3 Inputs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	7,521	5,704
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	$ 13,443	$ 14,467

Fair Value Measurements - Chang

Fair Value Measurements - Changes in Level 3 Assets Measured at Estimated Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation Calculation Roll Forward
Balance at the beginning of the year	$ 20,171	$ 21,385
Purchases	3,190	1,668
Settlements	(2,446)	(722)
Sales	(75)	(5,412)
Gains included in earnings	118	4,060
Total unrealized gains/(losses)	6	(808)
Balance at the end of the period	$ 20,964	$ 20,171

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument Fair Value Disclosure [Abstract]
Transfer of securities between levels of fair value hierarchy	$ 0	$ 0
Days from origination after which mortgage loan 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	Dec. 31, 2018	Dec. 31, 2017
Impaired Loans (Less Specific Allowance) [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Total Fair Value	$ 34,396	$ 34,041
Repossessed Assets [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Total Fair Value	183	288
Other Real Estate Owned [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Total Fair Value	$ 4,683	$ 1,995

Fair Value Measurements - Estim

Fair Value Measurements - Estimated Fair Values of Company's Financial Instruments (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
FINANCIAL ASSETS
Securities held for investment, Carrying Amount	$ 1,428	$ 2,292
Loans, net of allowance for loan losses, Carrying Amount	4,924,587	4,670,329
Securities held for investment, Fair Value	1,433	2,303
Loans held for sale, Fair Value	8,174	6,173
FINANCIAL LIABILITIES
Deposits, Carrying Amount	6,605,495	6,415,045
Short-term borrowings, Carrying Amount	1,675	900
Junior subordinated debentures, Carrying Amount	26,804	31,959
OFF-BALANCE SHEET FINANCIAL INSTRUMENTS
Loan commitments, Fair Value	2,158	1,839
Letters of credit, Fair Value	421	428
Level 2 Inputs [Member]
FINANCIAL ASSETS
Cash and cash equivalents, Carrying Amount	1,424,255	1,758,575
Securities held for investment, Carrying Amount	928	1,792
Loans held for sale, Carrying Amount	8,174	6,173
Cash and cash equivalents, Fair Value	1,424,255	1,758,575
Securities held for investment, Fair Value	933	1,803
Loans held for sale, Fair Value	8,174	6,173
FINANCIAL LIABILITIES
Deposits, Carrying Amount	6,605,495	6,415,045
Short-term borrowings, Carrying Amount	1,675	900
Junior subordinated debentures, Carrying Amount	26,804	31,959
Deposits, Fair Value	6,713,542	6,490,309
Short-term borrowings, Fair Value	1,675	900
Junior subordinated debentures, Fair Value	29,549	34,661
Level 3 Inputs [Member]
FINANCIAL ASSETS
Securities held for investment, Carrying Amount	500	500
Loans, net of allowance for loan losses, Carrying Amount	4,924,587	4,670,329
Securities held for investment, Fair Value	500	500
Loans, net of allowance for loan losses, Fair Value	$ 4,901,159	$ 4,663,608

Segment Information - Additiona

Segment Information - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2018Business_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								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Net interest income (expense)	$ 66,888	$ 65,673	$ 64,880	$ 63,035	$ 58,699	$ 57,233	$ 56,439	$ 54,768	$ 260,476	$ 227,139	$ 203,828
Provision for loan losses	1,516	747	1,225	314	3,323	3,276	1,841	72	3,802	8,512	11,519
Noninterest income	31,851	$ 32,801	$ 30,437	$ 30,110	32,833	$ 29,169	$ 27,983	$ 28,085	125,199	118,070	107,032
Depreciation and amortization									13,546	11,791	12,383
Other expenses									208,575	188,601	179,021
Income before taxes									159,752	136,305	107,937
Total assets	7,574,258				7,253,156				7,574,258	7,253,156	7,018,952
Capital expenditures									51,863	18,007	10,835
Operating Segments [Member] | Metropolitan Banks [Member]
Segment Reporting Information [Line Items]
Net interest income (expense)									84,043	74,274	63,519
Provision for loan losses									79	2,457	2,229
Noninterest income									16,625	15,698	16,372
Depreciation and amortization									2,364	2,192	2,341
Other expenses									36,873	35,488	34,130
Income before taxes									61,352	49,835	41,191
Total assets	2,743,876				2,552,024				2,743,876	2,552,024	2,493,096
Capital expenditures									3,003	3,606	1,525
Operating Segments [Member] | Community Banks [Member]
Segment Reporting Information [Line Items]
Net interest income (expense)									170,096	147,731	135,508
Provision for loan losses									4,178	4,442	7,509
Noninterest income									60,004	54,353	57,745
Depreciation and amortization									9,092	7,790	8,281
Other expenses									106,674	93,619	96,627
Income before taxes									110,156	96,233	80,836
Total assets	4,892,946				4,544,196				4,892,946	4,544,196	4,412,174
Capital expenditures									21,393	12,334	7,738
Operating Segments [Member] | Other Financial Services [Member]
Segment Reporting Information [Line Items]
Net interest income (expense)									5,341	5,770	6,132
Provision for loan losses									(466)	1,767	1,653
Noninterest income									37,743	37,842	29,711
Depreciation and amortization									588	584	510
Other expenses									24,895	24,474	22,216
Income before taxes									18,067	16,787	11,464
Total assets	84,706				117,332				84,706	117,332	83,594
Capital expenditures									1,035	64	125
Operating Segments [Member] | Executive, Operations & Support [Member]
Segment Reporting Information [Line Items]
Net interest income (expense)									996	(636)	(1,331)
Provision for loan losses									11	(154)	128
Noninterest income									137,364	97,368	75,415
Depreciation and amortization									1,502	1,225	1,251
Other expenses									42,319	36,531	26,375
Income before taxes									94,528	59,130	46,330
Total assets	861,782				885,590				861,782	885,590	803,810
Capital expenditures									26,432	2,003	1,447
Eliminations [Member]
Segment Reporting Information [Line Items]
Noninterest income									(126,537)	(87,191)	(72,211)
Other expenses									(2,186)	(1,511)	(327)
Income before taxes									(124,351)	(85,680)	(71,884)
Total assets	$ (1,009,052)				$ (845,986)				$ (1,009,052)	$ (845,986)	$ (773,722)

Selected Quarterly Financial _3

Selected Quarterly Financial Data (Unaudited) - Summary of the Unaudited Quarterly Results of Operations (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Net interest income	$ 66,888	$ 65,673	$ 64,880	$ 63,035	$ 58,699	$ 57,233	$ 56,439	$ 54,768	$ 260,476	$ 227,139	$ 203,828
Provision for loan losses	1,516	747	1,225	314	3,323	3,276	1,841	72	3,802	8,512	11,519
Securities transactions	10	(64)	115	(14)	4,412	(22)	(330)		47	4,060	(59)
Noninterest income	31,851	32,801	30,437	30,110	32,833	29,169	27,983	28,085	125,199	118,070	107,032
Noninterest expense	56,166	55,809	54,256	55,890	51,251	50,600	48,953	49,588	222,121	200,392	191,404
Net income	$ 32,725	$ 32,883	$ 30,586	$ 29,620	$ 19,497	$ 21,710	$ 23,182	$ 22,050	$ 125,814	$ 86,439	$ 70,674
Net income per common share:
Basic	$ 1	$ 1.01	$ 0.93	$ 0.91	$ 0.61	$ 0.68	$ 0.73	$ 0.70	$ 3.85	$ 2.72	$ 2.27
Diluted	$ 0.98	$ 0.98	$ 0.91	$ 0.89	$ 0.59	$ 0.67	$ 0.71	$ 0.68	$ 3.76	$ 2.65	$ 2.22