Summary of Significant Accounting Policies (Policies)	12 Months Ended
Dec. 31, 2020
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation - The financial statements of Arrow and its wholly owned subsidiaries are consolidated and all material inter-company transactions have been eliminated. In the “Parent Company Only” financial statements in Note 21, the investment in wholly owned subsidiaries is carried under the equity method of accounting. When necessary, prior years’ Consolidated Financial Statements have been reclassified to conform to the current-year financial statement presentation. The Company determines whether it has a controlling financial interest in an entity by first evaluating whether the entity is a voting interest entity or a variable interest entity under GAAP. Voting interest entities are entities in which the total equity investment at risk is sufficient to enable the entity to finance itself independently and provides the equity holders with the obligation to absorb losses, the right to receive residual returns and the right to make decisions about the entity’s activities. The Company consolidates voting interest entities in which it has all, or at least a majority of, the voting interest. As defined in applicable accounting standards, variable interest entities (VIE) are entities that lack one or more of the characteristics of a voting interest entity. A controlling financial interest in a VIE is present when the Company has both the power and ability to direct the activities of the VIE that most significantly impact the VIE's economic performance and an obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. The Company’s wholly owned subsidiaries Arrow Capital Statutory Trust II and Arrow Capital Statutory Trust III are VIEs for which the Company is not the primary beneficiary. Accordingly, the accounts of these entities are not included in the Company’s Consolidated Financial Statements.
Segment Reporting	Segment Reporting - Arrow operations are primarily in the community banking industry, which constitutes Arrow’s only segment for financial reporting purposes. Arrow provides other services, such as trust administration, retirement plan administration, advice to the Company's proprietary mutual funds and insurance products, but these services do not rise to the quantitative thresholds for separate disclosure. Arrow operates primarily in the northeastern region of New York State in Warren, Washington, Saratoga, Essex, Clinton, Rensselaer, Albany, and Schenectady counties and surrounding areas.
Cash and Cash Equivalents	Cash and Cash Equivalents - Cash and cash equivalents include the following items: cash at branches, due from bank balances, cash items in the process of collection, interest-bearing bank balances and federal funds sold.
Securities	Securities - Management determines the appropriate classification of securities at the time of purchase. Securities reported as held-to-maturity are those debt securities which Arrow has both the positive intent and ability to hold to maturity and are stated at amortized cost. Securities available-for-sale are reported at fair value, with unrealized gains and losses reported in accumulated other comprehensive income or loss, net of taxes. Equity securities with readily determinable fair values are stated at fair value with realized and unrealized gains and losses reported in income.Realized gains and losses are based upon the amortized cost of the specific security sold. A decline in the fair value of any available-for-sale or held-to-maturity security below cost that is deemed to be other-than-temporary results in an impairment to reduce the carrying amount to fair value. To determine whether an impairment is other-than-temporary, all available information relevant to the collectability of the security is considered, including past events, current conditions, and reasonable and supportable forecasts when developing an estimate of cash flows expected to be collected. Evidence considered in this assessment includes the reasons for impairment, the severity and duration of the impairment, changes in value subsequent to year-end, forecasted performance of the investee, and the general market condition in the geographic area or industry the investee operates in. When an other-than-temporary impairment has occurred on a debt security, the amount of the other-than-temporary impairment recognized in earnings depends on whether the Company intends to sell the debt security or if it is more likely than not that the Company will be required to sell the debt security before recovery of its amortized cost basis less any current-period credit loss. If it is more likely than not that the Company will be required to sell the debt security before recovery of its amortized cost basis less any current-period credit loss, the other-than-temporary impairment is recognized in earnings equal to the entire difference between the investment’s amortized cost basis and its fair value at the balance sheet date. If the Company does not intend to sell the debt security and it is not more likely than not that the Company will be required to sell the debt security before recovery of its amortized cost basis, the other-than-temporary impairment is separated into the amount representing the credit loss and the amount related to all other factors. The amount of the total other-than-temporary impairment related to the credit loss is recognized in earnings. The amount of the total other-than-temporary impairment related to other factors is recognized in other comprehensive income, net of applicable income taxes. Investments in Federal Reserve Bank and Federal Home Loan Bank (“FHLB”) stock are required for membership in those organizations and are carried at cost since there is no market value available. The FHLB New York continues to pay dividends and repurchase stock. As such, the Company has not recognized any impairment on its holdings of Federal Reserve Bank and FHLB stock.
Loans and Allowance for Loan Losses	Loans and Allowance for Loan Losses - Loans are reported at their principal outstanding balance, net of deferred fees and costs, and unearned income. Arrow has the intent and ability to hold to maturity. Interest income on loans is accrued and credited to income based upon the principal amount outstanding. Loan fees and costs directly associated with loan originations are deferred and amortized/accreted as an adjustment to yield over the lives of the loans originated. Arrow originated loans to commercial borrowers under the PPP during 2020. PPP loans have an interest rate of 1% and include an origination and servicing fee as a result of originating these loans. The original term on the PPP loans is two years, however the borrower will have the option to apply for forgiveness. Subsequent to the funding of the loans, additional guidance was provided permitting the term of a PPP loan to be extended to five years if both parties agree to the revised terms. Arrow is recognizing the fees earned over the life of the loan and will accelerate recognition of the fees if the loan is forgiven by the Small Business Administration. From time-to-time, Arrow has sold (most with servicing retained) residential real estate loans at or shortly after origination. Any gain or loss on the sale of loans, along with the value of the servicing right, is recognized at the time of sale as the difference between the recorded basis in the loan and net proceeds from the sale. Loans held for sale are recorded at the lower of cost or fair value on an aggregate basis. Loans are placed on nonaccrual status either due to the delinquency status of principal and/or interest or a judgment by management that the full repayment of principal and interest is unlikely. Unless already placed on nonaccrual status, loans secured by home equity lines of credit are put on nonaccrual status when 120 days past due; residential real estate loans when 150 days past due; commercial and commercial real estate loans are evaluated on a loan-by-loan basis and are placed on nonaccrual status when 90 days past due if the full collection of principal and interest is uncertain; all other loans are to be moved to nonaccrual status upon the earliest occurrence of repossession, bankruptcy, delinquency of 90 days or more unless the loan is secured and in the process of collection with no loss anticipated or when full collection of principal and interest is in doubt. The balance of any accrued interest deemed uncollectible at the date the loan is placed on nonaccrual status is reversed, generally against interest income. A loan is returned to accrual status at the later of the date when the past due status of the loan falls below the threshold for nonaccrual status or management deems that it is likely that the borrower will repay all interest and principal. For payments received while the loan is on nonaccrual status, Arrow may recognize interest income on a cash basis if the repayment of the remaining principal and accrued interest is deemed likely. The allowance for loan losses is maintained by charges to operations based upon the Company's best estimate of the probable amount of loans that will not be able to collected based on current information. Provisions to the allowance for loan losses are offset by actual loan charge-offs (net of any recoveries). The loan portfolio is evaluated for potential charge-offs on a monthly basis. In general, automobile and other consumer loans are charged-off when 120 days delinquent. Residential real estate loans are charged-off when a loss becomes known or based on a new appraisal at the earlier of 180 days past due or repossession. Commercial and commercial real estate loans are evaluated early in their delinquency status and are charged-off when management concludes that not all principal will be repaid from on-going cash flows or liquidation of collateral. An evaluation of estimated proceeds from the liquidation of the loan’s collateral is compared to the loan carrying amount and a charge to the allowance for loan losses is taken for any deficiency. While management uses available information to recognize losses on loans, future additions to the allowance may be necessary based on changes in economic conditions in Arrow's market area. In addition, various Federal regulatory agencies, as an integral part of their examination process, review Arrow's allowance for loan losses. Such agencies may require Arrow to recognize additions to the allowance in future periods, based on their judgments about information available to them at the time of their examination, which may not be currently available to management. All nonaccrual loans over $250 thousand and all troubled debt restructured loans are considered to be impaired loans and these loans are evaluated individually to determine the amount of impairment, if any. The amount of impairment, if any, related to individual impaired loans is measured based on either the present value of expected future cash flows discounted at the loan's effective interest rate, the loan's observable market price or the fair value of the collateral if the loan is collateral dependent. Arrow determines impairment for collateral dependent loans based on the fair value of the collateral less estimated costs to sell. Any excess of the recorded investment in the collateral dependent impaired loan over the estimated collateral value, less costs to sell, is typically charged off. For impaired loans which are not collateral dependent, impairment is measured by comparing the recorded investment in the loan to the present value of the expected cash flows, discounted at the loan’s effective interest rate. If this amount is less than the recorded investment in the loan, an impairment reserve is recognized as part of the allowance for loan losses, or based upon the judgment of management all or a portion of the excess of the recorded investment in the loan over the present value of the estimated future cash flow may be charged off. The allowance for loan losses on the remaining loans is primarily determined based upon consideration of the historical net loss factor incorporating a rolling average annual twelve quarter look-back period of the respective segment that have occurred within each pool of loans over the loss emergence period (LEP), adjusted as necessary based upon consideration of qualitative considerations impacting the inherent risk of loss in the respective loan portfolios. The LEP is an estimate of the average amount of time from the point at which a loss is incurred on a loan to the point at which the loss is recognized in the financial statements. Since the LEP may change under various economic environments, the LEP calculation is updated on an annual basis. In addition to historical net loss factors, qualitative factors that impact the inherent risk of loss associated with the loan categories within total loan portfolio are evaluated. These include: •Changes in the volume and severity of past due, nonaccrual and adversely classified loans •Changes in the nature and volume of the portfolio and in the terms of loans •Changes in the value of the underlying collateral for collateral dependent loans •Changes in lending policies and procedures, including changes in underwriting standards and collection, charge-off, and recovery practices not considered elsewhere in estimating loan losses •Changes in the quality of the loan review system •Changes in the experience, ability, and depth of lending management and other relevant staff •Changes in international, national, regional, and local economic and business conditions and developments that affect the collectability of the portfolio •The existence and effect of any concentrations of credit, and changes in the level of such concentrations •The effect of other external factors such as competition and legal and regulatory requirements on the level of estimated loan losses in the existing portfolio or pool In management’s opinion, the balance of the allowance for loan losses, at each balance sheet date, is sufficient to provide for probable loan losses inherent in the corresponding loan portfolio.
Comprehensive Income (Loss)	Comprehensive Income (Loss) - For the Company, comprehensive income (loss) represents net income plus unrealized net securities holding gains or losses arising during the year (net of taxes), net retirement plan gain or loss (net of taxes), net retirement plan prior service cost (net of taxes), amortization of net retirement plan actuarial gain or loss (net of taxes) and amortization of net retirement plan prior service credit or cost (net of taxes) and is presented in the Consolidated Statements of Comprehensive Income (Loss) and Consolidated Statements of Changes in Shareholders’ Equity. Accumulated other comprehensive income (loss) represents the unrealized net securities holding gains or losses arising during the year (net of taxes), net retirement plan gain or loss (net of taxes), net retirement plan prior service cost (net of taxes), amortization of net retirement plan actuarial gain or loss (net of taxes) and amortization of net retirement plan prior service credit or cost (net of taxes) in the Company’s defined-benefit retirement and pension plan, supplemental employee retirement plan, and post-retirement life and healthcare benefit plan.
Revenue Recognition	Revenue Recognition - The following is a description of principal activities from which the Company generates its revenue from noninterest income sources. Income from Fiduciary Activities: represents revenue derived mainly through the management of client investments which is based on the market value of the covered assets and the fee schedule contained in the applicable account management agreement. Since the revenue is mainly based on the market value of assets, this amount can be volatile as financial markets increase and decrease based on various economic factors. The terms of the account management agreements generally specify that the performance obligations are completed each quarter. Accordingly, the Company mainly recognizes revenue from fiduciary activities on a quarterly basis. Fees for Other Services to Customers: represents general service fees for monthly deposit account maintenance and account activity plus fees from other deposit-based services. Revenue is recognized when the performance obligation is completed, which is generally on a monthly basis for account maintenance services, or upon the completion of a deposit-related transaction. Payment for these performance obligations is generally received at the time the performance obligations are satisfied. Insurance Commissions: represents commissions and fees paid by insurance carriers for both property and casualty insurance policies, and for services performed for employment benefits clients. Revenue from the property and casualty insurance business is recognized when the performance obligation is satisfied, which is generally the effective date of the bound coverage since there are no significant performance obligations remaining. Revenue from the employment benefit brokerage business is recognized when the benefit servicing performance obligations are satisfied, generally on a monthly basis.
Other Real Estate Owned and Repossessed Assets	Other Real Estate Owned and Repossessed Assets - Real estate acquired by foreclosure and assets acquired by repossession are recorded at the fair value of the property less estimated costs to sell at the time of repossession. Subsequent declines in fair value, after transfer to other real estate owned and repossessed assets are recognized through a valuation allowance. Such declines in fair value along with related operating expenses to administer such properties or assets are charged directly to operating expense.
Premises and Equipment	Premises and Equipment - Premises and equipment are stated at cost, less accumulated depreciation and amortization. Depreciation and amortization included in operating expenses are computed largely on the straight-line method. Depreciation is based on the estimated useful lives of the assets (buildings and improvements 20-40 years; furniture and equipment 7-10 years; data processing equipment 5-7 years) and, in the case of leasehold improvements, amortization is computed over the terms of the respective leases or their estimated useful lives, whichever is shorter. Gains or losses on disposition are reflected in earnings.
Leases	Leases - The Company recognizes right-of-use assets and lease liabilities on the balance sheet for all leases with terms longer than 12 months, and has elected not to separate lease and non-lease components, but accounts for the resulting combined component as a single lease component. The Company also elected to account for short-term leases, those leases with a "lease term" of twelve months or less, as an operating lease. Since the Company has not been able to determine the rate implicit in its leases, the secured borrowing rate from the Federal Home Loan Bank of New York is utilized to determine the lease discount rate. The expected expiration date of each new lease is determined on a lease-by-lease basis based on certain criteria, such as the availability of renewal options in the lease contracts, the amount of leasehold improvements required in addition to the feasibility of growth potential.
Investments in Real Estate Limited Partnerships	Investments in Real Estate Limited Partnerships - These limited partnerships acquire, develop and operate low and moderate-income housing. As a limited partner in these projects, Arrow receives low income housing tax credits and tax deductions for losses incurred by the underlying properties. The proportional amortization method allowed in Accounting Standards Update 2014-01 "Investments - Equity Method and Joint Ventures (Topic 323): Accounting for Investments in Qualified Affordable Housing Projects" is applied. The proportional amortization method permits an entity to amortize the initial cost of the investment in proportion to the amount of the tax credits and other tax benefits received and to recognize the net investment performance in the income statement as a component of income tax expense.
Investments in Historical Tax Credits	Investments in Historical Tax Credits - Arrow accounts for historic rehabilitation tax credits using the deferral method of accounting under which the tax benefit generated from an investment tax credit is recorded as a reduction to the GAAP asset basis. Accordingly, Arrow recognized a current tax receivable and a deferred tax asset and corresponding reduction in the basis of Arrow's historic tax credit investment.
Bank-Owned Life Insurance	Bank-Owned Life Insurance - Arrow has purchased life insurance policies on certain employees, key executives and directors. Bank-owned life insurance is recorded at the amount that can be realized under the insurance contract at the balance sheet date, which is the cash surrender value adjusted for other charges or other amounts due that are probable at settlement.
Derivative Instruments and Hedging Activities	Derivative Instruments and Hedging Activities - Arrow enters into interest rate swap agreements that are not designated as hedges for accounting purposes. As the interest rate swap agreements have substantially equivalent and offsetting terms, they do not present any material exposure to Arrow's consolidated statements of income. Arrow records its interest rate swap agreements at fair value and is presented on a gross basis within other assets and other liabilities on the consolidated balance sheets. Changes in the fair value of assets and liabilities arising from these derivatives are included, net, in other income in the consolidated statement of income. In addition, Arrow has entered into interest rate swaps to synthetically fix the variable rate interest payments in outstanding subordinated trust securities. These agreements are designated as cash flow hedges. For derivatives designated and that qualify as cash flow hedges of interest rate risk, the gain or loss on the derivative is recorded in Accumulated Other Comprehensive Income and subsequently reclassified into interest expense in the same period during which the hedge transaction affects earnings.
Income Taxes	Income Taxes - Arrow accounts for income taxes under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income tax expense in the period that includes the enactment date. Arrow’s policy is that deferred tax assets are reduced by a valuation allowance if, based on the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized.
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets - Identifiable intangible assets acquired in a business combination are capitalized and amortized. Any remaining unidentifiable intangible asset is classified as goodwill, for which amortization is not required but which must be evaluated for impairment. Arrow tests for impairment of goodwill on an annual basis, or when events and circumstances indicate potential impairment. In evaluating goodwill for impairment, Arrow first assesses certain qualitative factors to determine if it is more likely than not that the fair value of the reporting unit is less than its carrying value. If it is more likely than not that the fair value of a reporting unit exceeds its carrying amount, goodwill of the reporting unit is considered not impaired. If the carrying amount of a reporting unit exceeds its fair value, the second step of the goodwill impairment test is performed to measure the amount of impairment loss, if any.The carrying amounts of other recognized intangible assets that meet recognition criteria and for which separate accounting records have been maintained (mortgage servicing rights and customer intangibles), have been included in the consolidated balance sheet as “Other Intangible Assets, Net.”Arrow has sold residential real estate loans, primarily to Freddie Mac, with servicing retained. Mortgage servicing rights are recognized as an asset when loans are sold with servicing retained, by allocating the cost of an originated mortgage loan between the loan and servicing right based on estimated relative fair values. The cost allocated to the servicing right is capitalized as a separate asset and amortized in proportion to, and over the period of, estimated net servicing income. Capitalized mortgage servicing rights are evaluated for impairment by comparing the asset’s carrying value to its current estimated fair value. Fair values are estimated using a discounted cash flow approach, which considers future servicing income and costs, current market interest rates, and anticipated prepayment, and default rates. Impairment losses are recognized through a valuation allowance for servicing rights having a current fair value that is less than amortized cost on an aggregate basis. Adjustments to increase or decrease the valuation allowance are charged or credited to income as a component of other operating income.
Pension and Postretirement Benefits	Pension and Postretirement Benefits - Arrow maintains a non-contributory, defined benefit pension plan covering substantially all employees, a supplemental pension plan covering certain executive officers selected by the Board of Directors, and certain post-retirement medical, dental and life insurance benefits for employees and retirees. The costs of these plans, based on actuarial computations of current and future benefits for employees, are charged to current operating expenses. The cost of post-retirement benefits other than pensions is recognized on an accrual basis as employees perform services to earn the benefits. Arrow recognizes the overfunded or underfunded status of our single employer defined benefit pension plan as an asset or liability on its consolidated balance sheet and recognizes changes in the funded status in comprehensive income in the year in which the change occurred. Prior service costs or credits are amortized on a straight-line basis over the average remaining service period of active participants. Gains and losses in excess of 10% of the greater of the benefit obligation or the fair value of assets are amortized over the average remaining service period of active participants. The discount rate assumption is determined by preparing an analysis of the respective plan’s expected future cash flows and high-quality fixed-income investments currently available and expected to be available during the period to maturity of the pension benefits.
Stock-Based Compensation Plans	Stock-Based Compensation Plans - Arrow has three stock-based compensation plans, which are described more fully in Note 12, Stock Based Compensation. The Company expenses the grant date fair value of stock options and restricted stock units granted. For stock options and restricted stock units, the expense is recognized over the vesting period of the grant, typically four years for stock options and three years for restricted stock units, on a straight-line basis. Shares are generally issued from treasury for the exercise of stock options. Arrow sponsors an Employee Stock Purchase Plan ("ESPP") under which employees may purchase Arrow’s common stock at a 5% discount below market price at the time of purchase. This stock purchase plan is not considered a compensatory plan. Arrow maintains an employee stock ownership plan (“ESOP”). Substantially all employees of Arrow and its subsidiaries are eligible to participate upon satisfaction of applicable service requirements. The ESOP borrowed funds from one of Arrow’s subsidiary banks to purchase outstanding shares of Arrow’s common stock. The notes required annual payments of principal and interest through 2019. As the debt was repaid, shares were released from collateral based on the proportion of debt paid to total debt outstanding for the year and allocated to active employees. At December 31, 2020, there was no outstanding balance remaining on the loans and therefore no remaining unallocated shares. In addition, Arrow makes additional cash contributions to the Plan each year.
Securities Sold Under Agreements to Repurchase	Securities Sold Under Agreements to Repurchase - In securities repurchase agreements, Arrow receives cash from a counterparty in exchange for the transfer of securities to a third party custodian’s account that explicitly recognizes Arrow’s interest in the securities. These agreements are accounted for by Arrow as secured financing transactions, since it maintains effective control over the transferred securities, and meets other criteria for such accounting. Accordingly, the cash proceeds are recorded as borrowed funds, and the underlying securities continue to be carried in Arrow’s securities available-for-sale portfolio.
Earnings Per Share	Earnings Per Share (“EPS”) - Basic EPS excludes dilution and is computed by dividing income available to common stockholders by the weighted average number of common shares outstanding for the period. Diluted EPS reflects the potential dilution that could occur if 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 entity (such as Arrow’s stock options), computed using the treasury stock method. Unallocated common shares held by Arrow’s ESOP are not included in the weighted average number of common shares outstanding for either the basic or diluted EPS calculation.
Financial Instruments	Financial Instruments - Arrow is 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 commitments to extend credit and standby letters of credit. Commitments to extend credit include home equity lines of credit, commitments for residential and commercial construction loans and other personal and commercial lines of credit. These instruments involve, to varying degrees, elements of credit and interest rate risk in excess of the amount recognized in the consolidated balance sheets. The contract or notional amounts of those instruments reflect the extent of the involvement Arrow has in particular classes of financial instruments. Arrow's policy is to record such instruments when funded. Fair value estimates are made at a specific point in time, based on relevant market information and information about the financial instrument. These estimates do not reflect any premium or discount that could result from offering for sale at one time Arrow's entire holdings of a particular financial instrument. Because no market exists for a significant portion of Arrow's financial instruments, fair value estimates are based on judgments regarding future expected loss experience, current economic conditions, risk characteristics of various financial instruments, and other factors. These estimates are subjective in nature and involve uncertainties and matters of significant judgment and therefore cannot be determined with precision. Changes in assumptions could significantly affect the estimates. Fair value estimates are based on existing on- and off-balance sheet financial instruments without attempting to estimate the value of anticipated future business and the value of assets and liabilities that are not considered financial instruments. For example, Arrow has a wealth management department that contributes net fee income annually. The value of the wealth management department customer relationships is not considered a financial instrument of the Company, and therefore this value has not been incorporated into the fair value estimates. Other significant assets and liabilities that are not considered financial assets or liabilities include deferred taxes, premises and equipment, the value of low-cost, long-term core deposits and goodwill. In addition, the tax ramifications related to the realization of the unrealized gains and losses can have a significant effect on fair value estimates and have not been considered in any of the estimates. The fair value for loans is disclosed using the "exit price" notion which is a reasonable estimate of what another party might pay in an orderly transaction. Fair values for loans are calculated for portfolios of loans with similar financial characteristics. Loans are segregated by type such as commercial, commercial real estate, residential mortgage, indirect auto and other consumer loans. Each loan category is further segmented into fixed and adjustable interest rate terms and by performing and nonperforming categories. The fair value of performing loans is calculated by determining the estimated future cash flow, which is the contractual cash flow adjusted for estimated prepayments. The discount rate is determined by starting with current market yields, and adjusting for a discount spread. The discount spread is applied separately for each loan type based on market information. A liquidity premium is determined for each loan type based on market inefficiencies associated with the sale of a financial instrument. Finally, a credit loss component is determined utilizing the credit loss assumptions used in the allowance for loan and lease loss model. The carrying amount of short-term assets and liabilities is a reasonable estimate of fair value: cash and due from banks, federal funds sold and purchased, securities sold under agreements to repurchase, demand deposits, savings, N.O.W. and money market deposits, brokered money market deposits and time deposits, other short-term borrowings, accrued interest receivable and accrued interest payable. The fair value estimates of other on- and off-balance sheet financial instruments, as well as the method of arriving at fair value estimates, are included in the related footnotes and summarized in Note 17. Fair Value Measures - Arrow determines the fair value of financial instruments under the following hierarchy: •Level 1 – Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities; •Level 2 – Quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, or inputs that are observable, either directly or indirectly, for substantially the full term of the asset or liability; •Level 3 – Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity). A financial instrument’s level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement.
Management's Use of Estimates	Management’s Use of Estimates -The preparation of the Consolidated Financial Statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the Consolidated Financial Statements and the reported amounts of income and expenses during the reporting period. Our most significant estimates are the allowance for loan losses, the evaluation of other-than-temporary impairment of investment securities, goodwill impairment, pension and other postretirement liabilities and an analysis of a need for a valuation allowance for deferred tax assets. Actual results could differ from those estimates.A material estimate that is particularly susceptible to significant change in the near term is the allowance for loan losses. In connection with the determination of the allowance for loan losses, management obtains appraisals for properties. The allowance for loan losses is management’s best estimate of probable loan losses incurred as of the balance sheet date. While management uses available information to recognize losses on loans, future adjustments to the allowance for loan losses may be necessary based on changes in economic conditions.
New Accounting Pronouncements	The following accounting standards were adopted in 2020: In August 2018, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2018-13 "Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement" as part of its disclosure framework, and pursuant to which FASB has eliminated, amended and added disclosure requirements for fair value measurements. For Arrow, the standard became effective, on a prospective basis, on January 1, 2020. The adoption of this change in fair value disclosure did not have a material impact on its financial position or the results of operations in the period subsequent to its adoption. In August 2018, the FASB issued ASU 2018-14 "Disclosure Framework-Changes to the Disclosure Requirements for Defined Benefit Plans" which applies to all companies that provide defined benefit pension or other postretirement benefit plans for their employees. Certain disclosure requirements have been eliminated such as reporting the amounts in accumulated other comprehensive income expected to be recognized as components of net periodic benefit cost over the next year, and reporting the effects of a one-percentage-point change in the assumed healthcare cost trend rate on the aggregate of the service cost and interest cost components of net periodic benefit cost and on the benefit obligation for postretirement healthcare benefits. New required disclosures for reporting the weighted-average interest rate used to credit cash balance and similar plans that have a promised interest credit, the reasons for significant gains and losses affecting benefit obligations and other requirements for reporting aggregate information related to pension plans. For Arrow, the standard was adopted on December 31, 2020. The adoption of this standard affecting defined benefit plan disclosures did not have a material impact on its financial position or the results of operations. In August 2018, the FASB issued ASU 2018-15 "Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract" which will require companies to defer potentially significant, specified implementation costs incurred in a cloud computing arrangement that are currently often expensed under US GAAP. For Arrow, the standard was adopted, on a prospective basis, on January 1, 2020. The adoption of this standard did not have a material impact on its financial position or the results of operations in the period subsequent to its adoption. In October 2018, the FASB issued ASU No. 2018-17, Consolidation (Topic 810): Targeted Improvements to Related Party Guidance for Variable Interest Entities ("ASU 2018-17"). ASU 2018-17 provides that indirect interests held through related parties in common control arrangements should be considered on a proportional basis for determining whether fees paid to decision makers and service providers are variable interests. For Arrow, the standard was effective on January 1, 2020 and the adoption of this standard did not have a material impact on its financial position or the results of operations in the period subsequent to its adoption. In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting ("ASU 2020-04"). ASU 2020-04 provides companies with optional guidance to ease the potential accounting burden associated with transitioning away from reference rates that are expected to be discontinued, such as LIBOR. Companies can apply the ASU immediately. However, the guidance will only be available for a limited time (generally through December 31, 2022), and provides optional relief for contract modifications, hedge accounting and Held-to-maturity debt securities. For Arrow, this standard was effective January 1, 2020 and can be applied prospectively beginning January 1, 2020 for contract modifications and hedging relationships. The one-time election to sell and/or transfer securities classified as Held-to-maturity may be made at any point after March 12, 2020. Arrow is evaluating the impact of this standard as it will provide relief for contracts currently tied to LIBOR and hedge accounting relationships.
Fair Value Measurements	The fair value of financial instruments is determined under the following hierarchy: •Level 1 - Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities; •Level 2 - Quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, or inputs that are observable, either directly or indirectly, for substantially the full term of the asset or liability; •Level 3 - Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity). There were no transfers between Levels 1, 2 and 3 for the years ended December 31, 2020 or 2019. Fair Value Methodology for Assets and Liabilities Measured on a Recurring Basis The fair value of level 1 securities available-for-sale are based on unadjusted, quoted market prices from exchanges in active markets. The fair value of level 2 securities available-for-sale are based on an independent bond and equity pricing service for identical assets or significantly similar securities and an independent equity pricing service for equity securities not actively traded. The pricing services use a variety of techniques to arrive at fair value including market maker bids, quotes and pricing models. Inputs to the pricing models include recent trades, benchmark interest rates, spreads and actual and projected cash flows. The fair value of Level 2 derivatives is determined using inputs that are observable in the market place obtained from third parties including yield curves, publicly available volatilities, and floating indexes. Fair Value Methodology for Assets and Liabilities Measured on a Nonrecurring Basis The fair value of collateral dependent impaired loans and other real estate owned was based on third-party appraisals less estimated cost to sell. The appraisals may be adjusted by management for qualitative factors such as economic conditions and estimated liquidation expenses. Other assets which might have been included in this table include mortgage servicing rights, goodwill and other intangible assets. Arrow evaluates each of these assets for impairment on an annual basis, with no impairment recognized for these assets at December 31, 2020 and 2019. Fair Value Methodology for Financial Instruments Not Measured on a Recurring or Nonrecurring Basis The fair value for securities held-to-maturity is determined utilizing an independent bond pricing service for identical assets or significantly similar securities. The pricing service uses a variety of techniques to arrive at fair value including market maker bids, quotes and pricing models. Inputs to the pricing models include recent trades, benchmark interest rates, spreads and actual and projected cash flows. ASU 2016-01 "Recognition and Measurement of Financial Assets and Financial Liabilities" requires that the fair value for loans must be disclosed using the "exit price" notion which is a reasonable estimate of what another party might pay in an orderly transaction. Fair values for loans are calculated for portfolios of loans with similar financial characteristics. Loans are segregated by type such as commercial, commercial real estate, residential mortgage, indirect auto and other consumer loans. Each loan category is further segmented into fixed and adjustable interest rate terms and by performing and nonperforming categories. The fair value of performing loans is calculated by determining the estimated future cash flow, which is the contractual cash flow adjusted for estimated prepayments. The discount rate is determined by starting with current market yields, and first adjusting for a liquidity premium. This premium is separately determined for each loan type. Then a credit loss component is determined utilizing the credit loss assumptions used in the allowance for loan and lease loss model. Finally, a discount spread is applied separately for consumer loans vs. commercial loans based on market information and utilization of the swap curve. The fair value of time deposits is calculated using the replacement cost of funds approach, which is based on the discounted value of contractual cash flows. The discount rates are estimated using the Federal Home Loan Bank of New York ("FHLBNY") yield curve, which is considered representative of Arrow’s replacement cost of funds. A cash flow is generated separately to represent the functional cost of maintaining each account; this cash flow is discounted to FHLBNY yield curve, in conjunction with the contractual cash flows. The fair value of all other deposits is equal to the carrying value. The fair value of FHLBNY advances are as calculated by the FHLBNY. The carrying amount of FHLBNY and FRB stock approximates fair value. If the stock was redeemed, the Company will receive an amount equal to the par value of the stock. The fair value of the outstanding trust preferred securities (Junior Subordinated Obligations Issued to Unconsolidated Subsidiary Trusts) are equal to book value with adjustments for the fair market value of their associated interest rate swaps. The fair value is determined by starting with book value as these outstanding securities have a floating rate coupon that is tied to 3-month LIBOR. Through the use of interest rate swaps, the coupons are synthetically fixed, so an adjustment for market value of swap is applied. The market value of interest rate swaps are provided by a third party counterparty.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2020

Principles of Consolidation - The financial statements of Arrow and its wholly owned subsidiaries are consolidated and all material inter-company transactions have been eliminated. In the “Parent Company Only” financial statements in Note 21, the investment in wholly owned subsidiaries is carried under the equity method of accounting. When necessary, prior years’ Consolidated Financial Statements have been reclassified to conform to the current-year financial statement presentation.

The Company determines whether it has a controlling financial interest in an entity by first evaluating whether the entity is a voting interest entity or a variable interest entity under GAAP. Voting interest entities are entities in which the total equity investment at risk is sufficient to enable the entity to finance itself independently and provides the equity holders with the obligation to absorb losses, the right to receive residual returns and the right to make decisions about the entity’s activities. The Company consolidates voting interest entities in which it has all, or at least a majority of, the voting interest. As defined in applicable accounting standards, variable interest entities (VIE) are entities that lack one or more of the characteristics of a voting interest entity. A controlling financial interest in a VIE is present when the Company has both the power and ability to direct the activities of the VIE that most significantly impact the VIE's economic performance and an obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. The Company’s wholly owned subsidiaries Arrow Capital Statutory Trust II and Arrow Capital Statutory Trust III are VIEs for which the Company is not the primary beneficiary. Accordingly, the accounts of these entities are not included in the Company’s Consolidated Financial Statements.

Segment Reporting

Segment Reporting - Arrow operations are primarily in the community banking industry, which constitutes Arrow’s only segment for financial reporting purposes. Arrow provides other services, such as trust administration, retirement plan administration, advice to the Company's proprietary mutual funds and insurance products, but these services do not rise to the quantitative thresholds for separate disclosure. Arrow operates primarily in the northeastern region of New York State in Warren, Washington, Saratoga, Essex, Clinton, Rensselaer, Albany, and Schenectady counties and surrounding areas.

Cash and Cash Equivalents

Cash and Cash Equivalents - Cash and cash equivalents include the following items: cash at branches, due from bank balances, cash items in the process of collection, interest-bearing bank balances and federal funds sold.

Securities

Securities - Management determines the appropriate classification of securities at the time of purchase. Securities reported as held-to-maturity are those debt securities which Arrow has both the positive intent and ability to hold to maturity and are stated at amortized cost. Securities available-for-sale are reported at fair value, with unrealized gains and losses reported in accumulated other comprehensive income or loss, net of taxes. Equity securities with readily determinable fair values are stated at fair value with realized and unrealized gains and losses reported in income.Realized gains and losses are based upon the amortized cost of the specific security sold. A decline in the fair value of any available-for-sale or held-to-maturity security below cost that is deemed to be other-than-temporary results in an impairment to reduce the carrying amount to fair value. To determine whether an impairment is other-than-temporary, all available information relevant to the collectability of the security is considered, including past events, current conditions, and reasonable and supportable forecasts when developing an estimate of cash flows expected to be collected. Evidence considered in this assessment includes the reasons for impairment, the severity and duration of the impairment, changes in value subsequent to year-end, forecasted performance of the investee, and the general market condition in the geographic area or industry the investee operates in. When an other-than-temporary impairment has occurred on a debt security, the amount of the other-than-temporary impairment recognized in earnings depends on whether the Company intends to sell the debt security or if it is more likely than not that the Company will be required to sell the debt security before recovery of its amortized cost basis less any current-period credit loss. If it is more likely than not that the Company will be required to sell the debt security before recovery of its amortized cost basis less any current-period credit loss, the other-than-temporary impairment is recognized in earnings equal to the entire difference between the investment’s amortized cost basis and its fair value at the balance sheet date. If the Company does not intend to sell the debt security and it is not more likely than not that the Company will be required to sell the debt security before recovery of its amortized cost basis, the other-than-temporary impairment is separated into the amount representing the credit loss and the amount related to all other factors. The amount of the total other-than-temporary impairment related to the credit loss is recognized in earnings. The amount of the total other-than-temporary impairment related to other factors is recognized in other comprehensive income, net of applicable income taxes. Investments in Federal Reserve Bank and Federal Home Loan Bank (“FHLB”) stock are required for membership in those organizations and are carried at cost since there is no market value available. The FHLB New York continues to pay dividends and repurchase stock. As such, the Company has not recognized any impairment on its holdings of Federal Reserve Bank and FHLB stock.

Loans and Allowance for Loan Losses

Loans and Allowance for Loan Losses - Loans are reported at their principal outstanding balance, net of deferred fees and costs, and unearned income. Arrow has the intent and ability to hold to maturity. Interest income on loans is accrued and credited to income based upon the principal amount outstanding. Loan fees and costs directly associated with loan originations are deferred and amortized/accreted as an adjustment to yield over the lives of the loans originated.

Arrow originated loans to commercial borrowers under the PPP during 2020. PPP loans have an interest rate of 1% and include an origination and servicing fee as a result of originating these loans. The original term on the PPP loans is two years, however the borrower will have the option to apply for forgiveness. Subsequent to the funding of the loans, additional guidance was provided permitting the term of a PPP loan to be extended to five years if both parties agree to the revised terms. Arrow is recognizing the fees earned over the life of the loan and will accelerate recognition of the fees if the loan is forgiven by the Small Business Administration.

From time-to-time, Arrow has sold (most with servicing retained) residential real estate loans at or shortly after origination. Any gain or loss on the sale of loans, along with the value of the servicing right, is recognized at the time of sale as the difference between the recorded basis in the loan and net proceeds from the sale. Loans held for sale are recorded at the lower of cost or fair value on an aggregate basis.

Loans are placed on nonaccrual status either due to the delinquency status of principal and/or interest or a judgment by management that the full repayment of principal and interest is unlikely. Unless already placed on nonaccrual status, loans secured by home equity lines of credit are put on nonaccrual status when 120 days past due; residential real estate loans when 150 days past due; commercial and commercial real estate loans are evaluated on a loan-by-loan basis and are placed on nonaccrual status when 90 days past due if the full collection of principal and interest is uncertain; all other loans are to be moved to nonaccrual status upon the earliest occurrence of repossession, bankruptcy, delinquency of 90 days or more unless the loan is secured and in the process of collection with no loss anticipated or when full collection of principal and interest is in doubt.

The balance of any accrued interest deemed uncollectible at the date the loan is placed on nonaccrual status is reversed, generally against interest income. A loan is returned to accrual status at the later of the date when the past due status of the loan falls below the threshold for nonaccrual status or management deems that it is likely that the borrower will repay all interest and principal. For payments received while the loan is on nonaccrual status, Arrow may recognize interest income on a cash basis if the repayment of the remaining principal and accrued interest is deemed likely.

The allowance for loan losses is maintained by charges to operations based upon the Company's best estimate of the probable amount of loans that will not be able to collected based on current information. Provisions to the allowance for loan losses are offset by actual loan charge-offs (net of any recoveries). The loan portfolio is evaluated for potential charge-offs on a monthly basis. In general, automobile and other consumer loans are charged-off when 120 days delinquent. Residential real estate loans are charged-off when a loss becomes known or based on a new appraisal at the earlier of 180 days past due or repossession. Commercial and commercial real estate loans are evaluated early in their delinquency status and are charged-off when management concludes that not all principal will be repaid from on-going cash flows or liquidation of collateral. An evaluation of estimated proceeds from the liquidation of the loan’s collateral is compared to the loan carrying amount and a charge to the allowance for loan losses is taken for any deficiency. While management uses available information to recognize losses on loans, future additions to the allowance may be necessary based on changes in economic conditions in Arrow's market area. In addition, various Federal regulatory agencies, as an integral part of their examination process, review Arrow's allowance for loan losses. Such agencies may require Arrow to recognize additions to the allowance in future periods, based on their judgments about information available to them at the time of their examination, which may not be currently available to management.

All nonaccrual loans over $250 thousand and all troubled debt restructured loans are considered to be impaired loans and these loans are evaluated individually to determine the amount of impairment, if any. The amount of impairment, if any, related

to individual impaired loans is measured based on either the present value of expected future cash flows discounted at the loan's effective interest rate, the loan's observable market price or the fair value of the collateral if the loan is collateral dependent. Arrow determines impairment for collateral dependent loans based on the fair value of the collateral less estimated costs to sell. Any excess of the recorded investment in the collateral dependent impaired loan over the estimated collateral value, less costs to sell, is typically charged off. For impaired loans which are not collateral dependent, impairment is measured by comparing the recorded investment in the loan to the present value of the expected cash flows, discounted at the loan’s effective interest rate. If this amount is less than the recorded investment in the loan, an impairment reserve is recognized as part of the allowance for loan losses, or based upon the judgment of management all or a portion of the excess of the recorded investment in the loan over the present value of the estimated future cash flow may be charged off.

The allowance for loan losses on the remaining loans is primarily determined based upon consideration of the historical net loss factor incorporating a rolling average annual twelve quarter look-back period of the respective segment that have occurred within each pool of loans over the loss emergence period (LEP), adjusted as necessary based upon consideration of qualitative considerations impacting the inherent risk of loss in the respective loan portfolios. The LEP is an estimate of the average amount of time from the point at which a loss is incurred on a loan to the point at which the loss is recognized in the financial statements. Since the LEP may change under various economic environments, the LEP calculation is updated on an annual basis. In addition to historical net loss factors, qualitative factors that impact the inherent risk of loss associated with the loan categories within total loan portfolio are evaluated. These include:

•Changes in the volume and severity of past due, nonaccrual and adversely classified loans

•Changes in the nature and volume of the portfolio and in the terms of loans

•Changes in the value of the underlying collateral for collateral dependent loans

•Changes in lending policies and procedures, including changes in underwriting standards and collection, charge-off, and recovery practices not considered elsewhere in estimating loan losses

•Changes in the quality of the loan review system

•Changes in the experience, ability, and depth of lending management and other relevant staff

•Changes in international, national, regional, and local economic and business conditions and developments that affect the collectability of the portfolio

•The existence and effect of any concentrations of credit, and changes in the level of such concentrations

•The effect of other external factors such as competition and legal and regulatory requirements on the level of estimated loan losses in the existing portfolio or pool

In management’s opinion, the balance of the allowance for loan losses, at each balance sheet date, is sufficient to provide for probable loan losses inherent in the corresponding loan portfolio.

Comprehensive Income (Loss)

Comprehensive Income (Loss) - For the Company, comprehensive income (loss) represents net income plus unrealized net securities holding gains or losses arising during the year (net of taxes), net retirement plan gain or loss (net of taxes), net retirement plan prior service cost (net of taxes), amortization of net retirement plan actuarial gain or loss (net of taxes) and amortization of net retirement plan prior service credit or cost (net of taxes) and is presented in the Consolidated Statements of Comprehensive Income (Loss) and Consolidated Statements of Changes in Shareholders’ Equity. Accumulated other comprehensive income (loss) represents the unrealized net securities holding gains or losses arising during the year (net of taxes), net retirement plan gain or loss (net of taxes), net retirement plan prior service cost (net of taxes), amortization of net retirement plan actuarial gain or loss (net of taxes) and amortization of net retirement plan prior service credit or cost (net of taxes) in the Company’s defined-benefit retirement and pension plan, supplemental employee retirement plan, and post-retirement life and healthcare benefit plan.

Revenue Recognition

Revenue Recognition - The following is a description of principal activities from which the Company generates its revenue from noninterest income sources.

Income from Fiduciary Activities: represents revenue derived mainly through the management of client investments which is based on the market value of the covered assets and the fee schedule contained in the applicable account management agreement. Since the revenue is mainly based on the market value of assets, this amount can be volatile as financial markets increase and decrease based on various economic factors. The terms of the account management agreements generally specify that the performance obligations are completed each quarter. Accordingly, the Company mainly recognizes revenue from fiduciary activities on a quarterly basis.

Fees for Other Services to Customers: represents general service fees for monthly deposit account maintenance and account activity plus fees from other deposit-based services. Revenue is recognized when the performance obligation is completed, which is generally on a monthly basis for account maintenance services, or upon the completion of a deposit-related transaction. Payment for these performance obligations is generally received at the time the performance obligations are satisfied.

Insurance Commissions: represents commissions and fees paid by insurance carriers for both property and casualty insurance policies, and for services performed for employment benefits clients. Revenue from the property and casualty insurance business is recognized when the performance obligation is satisfied, which is generally the effective date of the bound coverage since there are no significant performance obligations remaining. Revenue from the employment benefit brokerage business is recognized when the benefit servicing performance obligations are satisfied, generally on a monthly basis.

Other Real Estate Owned and Repossessed Assets

Other Real Estate Owned and Repossessed Assets - Real estate acquired by foreclosure and assets acquired by repossession are recorded at the fair value of the property less estimated costs to sell at the time of repossession. Subsequent declines in fair value, after transfer to other real estate owned and repossessed assets are recognized through a valuation allowance. Such declines in fair value along with related operating expenses to administer such properties or assets are charged directly to operating expense.

Premises and Equipment

Premises and Equipment - Premises and equipment are stated at cost, less accumulated depreciation and amortization. Depreciation and amortization included in operating expenses are computed largely on the straight-line method. Depreciation is based on the estimated useful lives of the assets (buildings and improvements 20-40 years; furniture and equipment 7-10 years; data processing equipment 5-7 years) and, in the case of leasehold improvements, amortization is computed over the terms of the respective leases or their estimated useful lives, whichever is shorter. Gains or losses on disposition are reflected in earnings.

Leases

Leases - The Company recognizes right-of-use assets and lease liabilities on the balance sheet for all leases with terms longer than 12 months, and has elected not to separate lease and non-lease components, but accounts for the resulting combined component as a single lease component. The Company also elected to account for short-term leases, those leases with a "lease term" of twelve months or less, as an operating lease. Since the Company has not been able to determine the rate implicit in its leases, the secured borrowing rate from the Federal Home Loan Bank of New York is utilized to determine the lease discount rate. The expected expiration date of each new lease is determined on a lease-by-lease basis based on certain criteria, such as the availability of renewal options in the lease contracts, the amount of leasehold improvements required in addition to the feasibility of growth potential.

Investments in Real Estate Limited Partnerships

Investments in Real Estate Limited Partnerships - These limited partnerships acquire, develop and operate low and moderate-income housing. As a limited partner in these projects, Arrow receives low income housing tax credits and tax deductions for losses incurred by the underlying properties. The proportional amortization method allowed in Accounting Standards Update 2014-01 "Investments - Equity Method and Joint Ventures (Topic 323): Accounting for Investments in Qualified Affordable Housing Projects" is applied. The proportional amortization method permits an entity to amortize the initial cost of the investment in proportion to the amount of the tax credits and other tax benefits received and to recognize the net investment performance in the income statement as a component of income tax expense.

Investments in Historical Tax Credits

Investments in Historical Tax Credits - Arrow accounts for historic rehabilitation tax credits using the deferral method of accounting under which the tax benefit generated from an investment tax credit is recorded as a reduction to the GAAP asset basis. Accordingly, Arrow recognized a current tax receivable and a deferred tax asset and corresponding reduction in the basis of Arrow's historic tax credit investment.

Bank-Owned Life Insurance

Bank-Owned Life Insurance - Arrow has purchased life insurance policies on certain employees, key executives and directors. Bank-owned life insurance is recorded at the amount that can be realized under the insurance contract at the balance sheet date, which is the cash surrender value adjusted for other charges or other amounts due that are probable at settlement.

Derivative Instruments and Hedging Activities

Derivative Instruments and Hedging Activities - Arrow enters into interest rate swap agreements that are not designated as hedges for accounting purposes. As the interest rate swap agreements have substantially equivalent and offsetting terms, they do not present any material exposure to Arrow's consolidated statements of income. Arrow records its interest rate swap agreements at fair value and is presented on a gross basis within other assets and other liabilities on the consolidated balance sheets. Changes in the fair value of assets and liabilities arising from these derivatives are included, net, in other income in the consolidated statement of income.

In addition, Arrow has entered into interest rate swaps to synthetically fix the variable rate interest payments in outstanding subordinated trust securities. These agreements are designated as cash flow hedges. For derivatives designated and that qualify as cash flow hedges of interest rate risk, the gain or loss on the derivative is recorded in Accumulated Other Comprehensive Income and subsequently reclassified into interest expense in the same period during which the hedge transaction affects earnings.

Income Taxes

Income Taxes - Arrow accounts for income taxes under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income tax expense in the period that includes the enactment date. Arrow’s policy is that deferred tax assets are reduced by a valuation allowance if, based on the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized.

Goodwill and Other Intangible Assets

Goodwill and Other Intangible Assets - Identifiable intangible assets acquired in a business combination are capitalized and amortized. Any remaining unidentifiable intangible asset is classified as goodwill, for which amortization is not required but which must be evaluated for impairment. Arrow tests for impairment of goodwill on an annual basis, or when events and circumstances indicate potential impairment. In evaluating goodwill for impairment, Arrow first assesses certain qualitative factors to determine if it is more likely than not that the fair value of the reporting unit is less than its carrying value. If it is more likely than not that the fair value of a reporting unit exceeds its carrying amount, goodwill of the reporting unit is considered not impaired. If the carrying amount of a reporting unit exceeds its fair value, the second step of the goodwill impairment test is performed to measure the amount of impairment loss, if any.The carrying amounts of other recognized intangible assets that meet recognition criteria and for which separate accounting records have been maintained (mortgage servicing rights and customer intangibles), have been included in the consolidated balance sheet as “Other Intangible Assets, Net.”Arrow has sold residential real estate loans, primarily to Freddie Mac, with servicing retained. Mortgage servicing rights are recognized as an asset when loans are sold with servicing retained, by allocating the cost of an originated mortgage loan between the loan and servicing right based on estimated relative fair values. The cost allocated to the servicing right is capitalized as a separate asset and amortized in proportion to, and over the period of, estimated net servicing income. Capitalized mortgage servicing rights are evaluated for impairment by comparing the asset’s carrying value to its current estimated fair value. Fair values are estimated using a discounted cash flow approach, which considers future servicing income and costs, current market interest rates, and anticipated prepayment, and default rates. Impairment losses are recognized through a valuation allowance for servicing rights having a current fair value that is less than amortized cost on an aggregate basis. Adjustments to increase or decrease the valuation allowance are charged or credited to income as a component of other operating income.

Pension and Postretirement Benefits

Pension and Postretirement Benefits - Arrow maintains a non-contributory, defined benefit pension plan covering substantially all employees, a supplemental pension plan covering certain executive officers selected by the Board of Directors, and certain post-retirement medical, dental and life insurance benefits for employees and retirees. The costs of these plans, based on actuarial computations of current and future benefits for employees, are charged to current operating expenses. The cost of post-retirement benefits other than pensions is recognized on an accrual basis as employees perform services to earn the benefits. Arrow recognizes the overfunded or underfunded status of our single employer defined benefit pension plan as an asset or liability on its consolidated balance sheet and recognizes changes in the funded status in comprehensive income in the year in which the change occurred.

Prior service costs or credits are amortized on a straight-line basis over the average remaining service period of active participants. Gains and losses in excess of 10% of the greater of the benefit obligation or the fair value of assets are amortized over the average remaining service period of active participants.

The discount rate assumption is determined by preparing an analysis of the respective plan’s expected future cash flows and high-quality fixed-income investments currently available and expected to be available during the period to maturity of the pension benefits.

Stock-Based Compensation Plans

Stock-Based Compensation Plans - Arrow has three stock-based compensation plans, which are described more fully in Note 12, Stock Based Compensation. The Company expenses the grant date fair value of stock options and restricted stock units granted. For stock options and restricted stock units, the expense is recognized over the vesting period of the grant, typically four years for stock options and three years for restricted stock units, on a straight-line basis. Shares are generally issued from treasury for the exercise of stock options.

Arrow sponsors an Employee Stock Purchase Plan ("ESPP") under which employees may purchase Arrow’s common stock at a 5% discount below market price at the time of purchase. This stock purchase plan is not considered a compensatory plan.

Arrow maintains an employee stock ownership plan (“ESOP”). Substantially all employees of Arrow and its subsidiaries are eligible to participate upon satisfaction of applicable service requirements. The ESOP borrowed funds from one of Arrow’s subsidiary banks to purchase outstanding shares of Arrow’s common stock. The notes required annual payments of principal and interest through 2019. As the debt was repaid, shares were released from collateral based on the proportion of debt paid to total debt outstanding for the year and allocated to active employees. At December 31, 2020, there was no outstanding balance remaining on the loans and therefore no remaining unallocated shares. In addition, Arrow makes additional cash contributions to the Plan each year.

Securities Sold Under Agreements to Repurchase

Securities Sold Under Agreements to Repurchase - In securities repurchase agreements, Arrow receives cash from a counterparty in exchange for the transfer of securities to a third party custodian’s account that explicitly recognizes Arrow’s interest in the securities. These agreements are accounted for by Arrow as secured financing transactions, since it maintains effective control over the transferred securities, and meets other criteria for such accounting. Accordingly, the cash proceeds are recorded as borrowed funds, and the underlying securities continue to be carried in Arrow’s securities available-for-sale portfolio.

Earnings Per Share

Earnings Per Share (“EPS”) - Basic EPS excludes dilution and is computed by dividing income available to common stockholders by the weighted average number of common shares outstanding for the period. Diluted EPS reflects the potential dilution that could occur if 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 entity (such as Arrow’s stock options), computed using the treasury stock method. Unallocated common shares held by Arrow’s ESOP are not included in the weighted average number of common shares outstanding for either the basic or diluted EPS calculation.

Financial Instruments

Financial Instruments - Arrow is 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 commitments to extend credit and standby letters of credit. Commitments to extend credit include home equity lines of credit, commitments for residential and commercial construction loans and other personal and commercial lines of credit. These instruments involve, to varying degrees, elements of credit and interest rate risk in excess of the amount recognized in the consolidated balance sheets. The contract or notional amounts of those instruments reflect the extent of the involvement Arrow has in particular classes of financial instruments. Arrow's policy is to record such instruments when funded. Fair value estimates are made at a specific point in time,

based on relevant market information and information about the financial instrument. These estimates do not reflect any premium or discount that could result from offering for sale at one time Arrow's entire holdings of a particular financial instrument. Because no market exists for a significant portion of Arrow's financial instruments, fair value estimates are based on judgments regarding future expected loss experience, current economic conditions, risk characteristics of various financial instruments, and other factors. These estimates are subjective in nature and involve uncertainties and matters of significant judgment and therefore cannot be determined with precision. Changes in assumptions could significantly affect the estimates.

Fair value estimates are based on existing on- and off-balance sheet financial instruments without attempting to estimate the value of anticipated future business and the value of assets and liabilities that are not considered financial instruments. For example, Arrow has a wealth management department that contributes net fee income annually. The value of the wealth management department customer relationships is not considered a financial instrument of the Company, and therefore this value has not been incorporated into the fair value estimates. Other significant assets and liabilities that are not considered financial assets or liabilities include deferred taxes, premises and equipment, the value of low-cost, long-term core deposits and goodwill. In addition, the tax ramifications related to the realization of the unrealized gains and losses can have a significant effect on fair value estimates and have not been considered in any of the estimates.

The fair value for loans is disclosed using the "exit price" notion which is a reasonable estimate of what another party might pay in an orderly transaction. Fair values for loans are calculated for portfolios of loans with similar financial characteristics. Loans are segregated by type such as commercial, commercial real estate, residential mortgage, indirect auto and other consumer loans. Each loan category is further segmented into fixed and adjustable interest rate terms and by performing and nonperforming categories. The fair value of performing loans is calculated by determining the estimated future cash flow, which is the contractual cash flow adjusted for estimated prepayments. The discount rate is determined by starting with current market yields, and adjusting for a discount spread. The discount spread is applied separately for each loan type based on market information. A liquidity premium is determined for each loan type based on market inefficiencies associated with the sale of a financial instrument. Finally, a credit loss component is determined utilizing the credit loss assumptions used in the allowance for loan and lease loss model.

The carrying amount of short-term assets and liabilities is a reasonable estimate of fair value: cash and due from banks, federal funds sold and purchased, securities sold under agreements to repurchase, demand deposits, savings, N.O.W. and money market deposits, brokered money market deposits and time deposits, other short-term borrowings, accrued interest receivable and accrued interest payable. The fair value estimates of other on- and off-balance sheet financial instruments, as well as the method of arriving at fair value estimates, are included in the related footnotes and summarized in Note 17.

Fair Value Measures - Arrow determines the fair value of financial instruments under the following hierarchy:

•Level 1 – Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities;

•Level 2 – Quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, or inputs that are observable, either directly or indirectly, for substantially the full term of the asset or liability;

•Level 3 – Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity).

A financial instrument’s level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement.

Management's Use of Estimates

Management’s Use of Estimates -The preparation of the Consolidated Financial Statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the Consolidated Financial Statements and the reported amounts of income and expenses during the reporting period. Our most significant estimates are the allowance for loan losses, the evaluation of other-than-temporary impairment of investment securities, goodwill impairment, pension and other postretirement liabilities and an analysis of a need for a valuation allowance for deferred tax assets. Actual results could differ from those estimates.A material estimate that is particularly susceptible to significant change in the near term is the allowance for loan losses. In connection with the determination of the allowance for loan losses, management obtains appraisals for properties. The allowance for loan losses is management’s best estimate of probable loan losses incurred as of the balance sheet date. While management uses available information to recognize losses on loans, future adjustments to the allowance for loan losses may be necessary based on changes in economic conditions.

New Accounting Pronouncements

The following accounting standards were adopted in 2020:

In August 2018, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2018-13 "Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement" as part of its disclosure framework, and pursuant to which FASB has eliminated, amended and added disclosure requirements for fair value measurements. For Arrow, the standard became effective, on a prospective basis, on January 1, 2020. The adoption of this change in fair value disclosure did not have a material impact on its financial position or the results of operations in the period subsequent to its adoption.

In August 2018, the FASB issued ASU 2018-14 "Disclosure Framework-Changes to the Disclosure Requirements for Defined Benefit Plans" which applies to all companies that provide defined benefit pension or other postretirement benefit plans for their employees. Certain disclosure requirements have been eliminated such as reporting the amounts in accumulated other comprehensive income expected to be recognized as components of net periodic benefit cost over the next year, and reporting

the effects of a one-percentage-point change in the assumed healthcare cost trend rate on the aggregate of the service cost and interest cost components of net periodic benefit cost and on the benefit obligation for postretirement healthcare benefits. New required disclosures for reporting the weighted-average interest rate used to credit cash balance and similar plans that have a promised interest credit, the reasons for significant gains and losses affecting benefit obligations and other requirements for reporting aggregate information related to pension plans. For Arrow, the standard was adopted on December 31, 2020. The adoption of this standard affecting defined benefit plan disclosures did not have a material impact on its financial position or the results of operations.

In August 2018, the FASB issued ASU 2018-15 "Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract" which will require companies to defer potentially significant, specified implementation costs incurred in a cloud computing arrangement that are currently often expensed under US GAAP. For Arrow, the standard was adopted, on a prospective basis, on January 1, 2020. The adoption of this standard did not have a material impact on its financial position or the results of operations in the period subsequent to its adoption.

In October 2018, the FASB issued ASU No. 2018-17, Consolidation (Topic 810): Targeted Improvements to Related Party Guidance for Variable Interest Entities ("ASU 2018-17"). ASU 2018-17 provides that indirect interests held through related parties in common control arrangements should be considered on a proportional basis for determining whether fees paid to decision makers and service providers are variable interests. For Arrow, the standard was effective on January 1, 2020 and the adoption of this standard did not have a material impact on its financial position or the results of operations in the period subsequent to its adoption.

In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting ("ASU 2020-04"). ASU 2020-04 provides companies with optional guidance to ease the potential accounting burden associated with transitioning away from reference rates that are expected to be discontinued, such as LIBOR. Companies can apply the ASU immediately. However, the guidance will only be available for a limited time (generally through December 31, 2022), and provides optional relief for contract modifications, hedge accounting and Held-to-maturity debt securities. For Arrow, this standard was effective January 1, 2020 and can be applied prospectively beginning January 1, 2020 for contract modifications and hedging relationships. The one-time election to sell and/or transfer securities classified as Held-to-maturity may be made at any point after March 12, 2020. Arrow is evaluating the impact of this standard as it will provide relief for contracts currently tied to LIBOR and hedge accounting relationships.

Fair Value Measurements

The fair value of financial instruments is determined under the following hierarchy:

•Level 1 - Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities;

•Level 2 - Quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, or inputs that are observable, either directly or indirectly, for substantially the full term of the asset or liability;

•Level 3 - Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity).

There were no transfers between Levels 1, 2 and 3 for the years ended December 31, 2020 or 2019.

Fair Value Methodology for Assets and Liabilities Measured on a Recurring Basis

The fair value of level 1 securities available-for-sale are based on unadjusted, quoted market prices from exchanges in active markets. The fair value of level 2 securities available-for-sale are based on an independent bond and equity pricing service for identical assets or significantly similar securities and an independent equity pricing service for equity securities not actively traded. The pricing services use a variety of techniques to arrive at fair value including market maker bids, quotes and pricing models. Inputs to the pricing models include recent trades, benchmark interest rates, spreads and actual and projected cash flows. The fair value of Level 2 derivatives is determined using inputs that are observable in the market place obtained from third parties including yield curves, publicly available volatilities, and floating indexes.

Fair Value Methodology for Assets and Liabilities Measured on a Nonrecurring Basis

The fair value of collateral dependent impaired loans and other real estate owned was based on third-party appraisals less estimated cost to sell. The appraisals may be adjusted by management for qualitative factors such as economic conditions and estimated liquidation expenses. Other assets which might have been included in this table include mortgage servicing rights, goodwill and other intangible assets. Arrow evaluates each of these assets for impairment on an annual basis, with no impairment recognized for these assets at December 31, 2020 and 2019.

Fair Value Methodology for Financial Instruments Not Measured on a Recurring or Nonrecurring Basis

The fair value for securities held-to-maturity is determined utilizing an independent bond pricing service for identical assets or significantly similar securities. The pricing service uses a variety of techniques to arrive at fair value including market maker bids, quotes and pricing models. Inputs to the pricing models include recent trades, benchmark interest rates, spreads and actual and projected cash flows.

ASU 2016-01 "Recognition and Measurement of Financial Assets and Financial Liabilities" requires that the fair value for loans must be disclosed using the "exit price" notion which is a reasonable estimate of what another party might pay in an orderly transaction. Fair values for loans are calculated for portfolios of loans with similar financial characteristics. Loans are segregated by type such as commercial, commercial real estate, residential mortgage, indirect auto and other consumer loans. Each loan category is further segmented into fixed and adjustable interest rate terms and by performing and nonperforming categories. The fair value of performing loans is calculated by determining the estimated future cash flow, which is the contractual cash flow adjusted for estimated prepayments. The discount rate is determined by starting with current market yields, and first adjusting for a liquidity premium. This premium is separately determined for each loan type. Then a credit loss component is determined utilizing the credit loss assumptions used in the allowance for loan and lease loss model. Finally, a discount spread is applied separately for consumer loans vs. commercial loans based on market information and utilization of the swap curve.

The fair value of time deposits is calculated using the replacement cost of funds approach, which is based on the discounted value of contractual cash flows. The discount rates are estimated using the Federal Home Loan Bank of New York ("FHLBNY") yield curve, which is considered representative of Arrow’s replacement cost of funds. A cash flow is generated separately to

represent the functional cost of maintaining each account; this cash flow is discounted to FHLBNY yield curve, in conjunction with the contractual cash flows.

The fair value of all other deposits is equal to the carrying value. The fair value of FHLBNY advances are as calculated by the FHLBNY. The carrying amount of FHLBNY and FRB stock approximates fair value. If the stock was redeemed, the Company will receive an amount equal to the par value of the stock.

The fair value of the outstanding trust preferred securities (Junior Subordinated Obligations Issued to Unconsolidated Subsidiary Trusts) are equal to book value with adjustments for the fair market value of their associated interest rate swaps. The fair value is determined by starting with book value as these outstanding securities have a floating rate coupon that is tied to 3-month LIBOR. Through the use of interest rate swaps, the coupons are synthetically fixed, so an adjustment for market value of swap is applied. The market value of interest rate swaps are provided by a third party counterparty.