Description of Business and Summary of Significant Accounting Policies (Policies)	12 Months Ended
Dec. 31, 2019
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 (“BancFirst”), an Oklahoma state-chartered bank headquartered in Oklahoma City, Oklahoma. The Company also conducts operating activities through its wholly-owned subsidiary, Pegasus Bank (“Pegasus Bank”), a Texas state-chartered bank headquartered in Dallas, Texas. BancFirst and Pegasus Bank provide 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. BancFirst also offers trust services and acts as executor, administrator, trustee, transfer agent and in various other fiduciary capacities. Through its Technology and Operations Center, BancFirst 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, Pegasus Bank, 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 2018 and 2017 have been reclassified to conform to the 2019 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 U.S. GAAP 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 83% of the portfolio, with junior liens comprising approximately 8%, 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.
Leases	Leases Certain operating leases are included as right of use lease assets in accrued interest receivable and other assets on the balance sheet and a related lease liability is included in accrued interest payable and other liabilities on the balance sheet. Right of use assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. The lease liability is measured as the present value of the unpaid lease payments, and the right of use assets value is derived from the calculation of the lease liability. To calculate the discount rate for each lease, the Company uses the rate implicit in the lease if available, otherwise an appropriate FHLB advance borrowing rate is used that correlates with the term of the lease.
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 were 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 were adjusted to fair value periodically, if impaired.
Advertising Costs	Advertising Costs Advertising costs are expensed as incurred. Advertising costs for the year ended December 31, 2019 were $3.8 million. Advertising costs for the years ended December 31, 2018 and 2017 were $3.5 million and $3.4 million, respectively.
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.
Revenue Recognition	Revenue Recognition In addition to lending and related activities, the Company offers various services to customers that generate revenue. Contract performance typically occurs in one year or less. Incremental costs of obtaining a contract are expensed when incurred when the amortization period is one year or less. Sales of real estate The sale of real estate property is generally recognized, along with any associated gain or loss, when control of the property transfers to the buyer. Service and transaction fees on depository accounts Customers often pay certain fees to the bank to access the cash on deposit including certain non-transactional fees such as account maintenance or dormancy fees, and certain transaction based fees such as ATM, wire transfer, or foreign exchange fees. Revenue is recognized when the transactions occur or as services are performed over primarily monthly or quarterly periods. Payment is typically received in the period the transactions occur, or in some cases, within 90 days of the service period. Interchange Fees Interchange fees, or “swipe” fees, are charges that merchants pay to the processors who, in turn, share that revenue with us and other card-issuing banks for processing electronic payment transactions. Interchange fees represent the portion of the debit card transaction amount that the card issuer retains to compensate it for processing transactions and providing rewards. Interchange fees are settled and recognized on a daily or monthly basis. Insurance Commissions and Fees Insurance commissions are received on the sale of insurance products, and revenue is recognized upon the placement date of the insurance policies or when such commissions are received. Payment is normally received within the policy period. In addition to placement, the Company also provides insurance policy related risk management services. Revenue is recognized as these services are provided. Performance-based commissions are recognized when received or earlier when, upon consideration of past results and current condition, the revenue is deemed not probable of reversal. For accounts billed by BancFirst Insurance Services, Inc., commission revenue is recognized at the later of the billing date or the effective date of the related insurance policies. Commission revenue, for accounts that are directly billed by the insurance company to the insured, is recognized when determinable by BancFirst Insurance Services, Inc., which is generally when such commissions are received. BancFirst Insurance Services, Inc. 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 they place. Contingent commissions from insurance companies are recognized when determinable, which is generally when such commissions are received. Trust BancFirst offers trust services and acts as executor, administrator, trustee, transfer agent and in various other fiduciary capacities. There are four basic types of fees that are included in the trust department income. Administrative fees are assessed for managing trust accounts. Shareholder fees are received in connection with holding specific fund share classes. In return for these services, the mutual fund (or its distributor or investment advisor) pay a fee to BancFirst. Oil and gas fees are assessed for management of oil and gas related activities. There are also other types of fees charged on a one time basis such as those related to opening and closing trust accounts. BancFirst records trust fees on a monthly, quarterly or annual basis based on the size of the asset being managed. Fees may be fixed or, where applicable, based on a percentage of transaction size of managed assets. These fees are recorded as revenue at the time the fee is billed, according to the agreement with the customer.
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 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-02, “Leases - (Topic 842)”, amended by ASU 2018-11, “Leases – (Topic 842)”: Targeted Improvements. This new guidance requires a lessee to recognize on the balance sheet the assets and liabilities for the rights and obligations created by leases with lease terms of more than twelve months and provide additional disclosures. The amendments were effective for annual periods, and interim reporting periods within those annual periods, beginning after December 15, 2018. The Company adopted this new standard on January 1, 2019, using a modified retrospective transition approach and recognized right-of-use lease assets and related lease liabilities totaling $4.3 million. The Company elected to apply certain practical adoption expedients provided under the updates whereby it did not reassess initial direct costs for any existing leases. No cumulative-effect adjustment was recognized as the amount was not material, and the impact on our results of operations and cash flows was also not material. No prior periods were adjusted. See Note (20) for the financial position impact and additional disclosures. 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. The Company expects to adopt the standard in the first quarter of 2020. In June 2016, the FASB issued ASU No. 2016-13, “Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” ASU 2016-13 requires a financial asset measured at amortized cost basis to be presented at the net amount expected to be collected. The measurement of expected credit losses is based on relevant information about past events, including historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. ASU 2016-13 requires enhanced disclosures related to the significant estimates and judgements used in estimating credit losses, as well as the credit quality and underwriting standards of an organization’s portfolio. In addition, ASU 2016-13 amends the accounting for credit losses on available-for-sale debt securities and purchased financial assets with credit deterioration. ASU 2016-13 will be effective for the Company on January 1, 2020. The Company believes under current assumptions the adoption will result in a 0-5% decrease in our allowance for loan loss. The Company is currently finalizing the execution of its implementation controls and processes, the ultimate impact of the adoption of ASU 2016-13 as of January 1, 2020 could differ from its current assumptions. Furthermore, ASU 2016-13 will necessitate that the Company establish an allowance for expected credit losses for certain debt securities and other financial assets. The Company expects to adopt the standard in the first quarter of 2020.

Description of Business and Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2019

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 (“BancFirst”), an Oklahoma state-chartered bank headquartered in Oklahoma City, Oklahoma. The Company also conducts operating activities through its wholly-owned subsidiary, Pegasus Bank (“Pegasus Bank”), a Texas state-chartered bank headquartered in Dallas, Texas. BancFirst and Pegasus Bank provide 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. BancFirst also offers trust services and acts as executor, administrator, trustee, transfer agent and in various other fiduciary capacities. Through its Technology and Operations Center, BancFirst 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, Pegasus Bank, 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 2018 and 2017 have been reclassified to conform to the 2019 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 U.S. GAAP 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 83% of the portfolio, with junior liens comprising approximately 8%, 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.

Leases

Certain operating leases are included as right of use lease assets in accrued interest receivable and other assets on the balance sheet and a related lease liability is included in accrued interest payable and other liabilities on the balance sheet. Right of use assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. The lease liability is measured as the present value of the unpaid lease payments, and the right of use assets value is derived from the calculation of the lease liability. To calculate the discount rate for each lease, the Company uses the rate implicit in the lease if available, otherwise an appropriate FHLB advance borrowing rate is used that correlates with the term of the lease.

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 were 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 were adjusted to fair value periodically, if impaired.

Advertising Costs

Advertising costs are expensed as incurred. Advertising costs for the year ended December 31, 2019 were $3.8 million. Advertising costs for the years ended December 31, 2018 and 2017 were $3.5 million and $3.4 million, respectively.

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.

Revenue Recognition

In addition to lending and related activities, the Company offers various services to customers that generate revenue. Contract performance typically occurs in one year or less. Incremental costs of obtaining a contract are expensed when incurred when the amortization period is one year or less.

Sales of real estate

The sale of real estate property is generally recognized, along with any associated gain or loss, when control of the property transfers to the buyer.

Service and transaction fees on depository accounts

Customers often pay certain fees to the bank to access the cash on deposit including certain non-transactional fees such as account maintenance or dormancy fees, and certain transaction based fees such as ATM, wire transfer, or foreign exchange fees. Revenue is recognized when the transactions occur or as services are performed over primarily monthly or quarterly periods. Payment is typically received in the period the transactions occur, or in some cases, within 90 days of the service period.

Interchange Fees

Interchange fees, or “swipe” fees, are charges that merchants pay to the processors who, in turn, share that revenue with us and other card-issuing banks for processing electronic payment transactions. Interchange fees represent the portion of the debit card transaction amount that the card issuer retains to compensate it for processing transactions and providing rewards. Interchange fees are settled and recognized on a daily or monthly basis.

Insurance Commissions and Fees

Insurance commissions are received on the sale of insurance products, and revenue is recognized upon the placement date of the insurance policies or when such commissions are received. Payment is normally received within the policy period. In addition to placement, the Company also provides insurance policy related risk management services. Revenue is recognized as these services are provided. Performance-based commissions are recognized when received or earlier when, upon consideration of past results and current condition, the revenue is deemed not probable of reversal.

For accounts billed by BancFirst Insurance Services, Inc., commission revenue is recognized at the later of the billing date or the effective date of the related insurance policies. Commission revenue, for accounts that are directly billed by the insurance company to the insured, is recognized when determinable by BancFirst Insurance Services, Inc., which is generally when such commissions are received.

BancFirst Insurance Services, Inc. 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 they place. Contingent commissions from insurance companies are recognized when determinable, which is generally when such commissions are received.

Trust

BancFirst offers trust services and acts as executor, administrator, trustee, transfer agent and in various other fiduciary capacities. There are four basic types of fees that are included in the trust department income. Administrative fees are assessed for managing trust accounts. Shareholder fees are received in connection with holding specific fund share classes. In return for these services, the mutual fund (or its distributor or investment advisor) pay a fee to BancFirst. Oil and gas fees are assessed for management of oil and gas related activities. There are also other types of fees charged on a one time basis such as those related to opening and closing trust accounts. BancFirst records trust fees on a monthly, quarterly or annual basis based on the size of the asset being managed. Fees may be fixed or, where applicable, based on a percentage of transaction size of managed assets. These fees are recorded as revenue at the time the fee is billed, according to the agreement with the customer.

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 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-02, “Leases - (Topic 842)”, amended by ASU 2018-11, “Leases – (Topic 842)”: Targeted Improvements. This new guidance requires a lessee to recognize on the balance sheet the assets and liabilities for the rights and obligations created by leases with lease terms of more than twelve months and provide additional disclosures. The amendments were effective for annual periods, and interim reporting periods within those annual periods, beginning after December 15, 2018. The Company adopted this new standard on January 1, 2019, using a modified retrospective transition approach and recognized right-of-use lease assets and related lease liabilities totaling $4.3 million. The Company elected to apply certain practical adoption expedients provided under the updates whereby it did not reassess initial direct costs for any existing leases. No cumulative-effect adjustment was recognized as the amount was not material, and the impact on our results of operations and cash flows was also not material. No prior periods were adjusted. See Note (20) for the financial position impact and additional disclosures.

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. The Company expects to adopt the standard in the first quarter of 2020.

In June 2016, the FASB issued ASU No. 2016-13, “Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” ASU 2016-13 requires a financial asset measured at amortized cost basis to be presented at the net amount expected to be collected. The measurement of expected credit losses is based on relevant information about past events, including historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. ASU 2016-13 requires enhanced disclosures related to the significant estimates and judgements used in estimating credit losses, as well as the credit quality and underwriting standards of an organization’s portfolio. In addition, ASU 2016-13 amends the accounting for credit losses on available-for-sale debt securities and purchased financial assets with credit deterioration. ASU 2016-13 will be effective for the Company on January 1, 2020. The Company believes under current assumptions the adoption will result in a 0-5% decrease in our allowance for loan loss. The Company is currently finalizing the execution of its implementation controls and processes, the ultimate impact of the adoption of ASU 2016-13 as of January 1, 2020 could differ from its current assumptions. Furthermore, ASU 2016-13 will necessitate that the Company establish an allowance for expected credit losses for certain debt securities and other financial assets. The Company expects to adopt the standard in the first quarter of 2020.