Accounting Policies	3 Months Ended
Mar. 31, 2026
Accounting Policies [Abstract]
Accounting Policies	ACCOUNTING POLICIES The accompanying unaudited interim Consolidated Financial Statements contain all of the adjustments necessary to present fairly the financial position as of March 31, 2026 and December 31, 2025; the results of operations for the three month periods ended March 31, 2026 and 2025; the consolidated statements of comprehensive income for the three month periods ended March 31, 2026 and 2025; the changes in stockholders' equity for the three month periods ended March 31, 2026 and 2025; and the cash flows for the three month periods ended March 31, 2026 and 2025. All such adjustments are of a normal recurring nature. The unaudited interim Consolidated Financial Statements should be read in conjunction with the audited annual Consolidated Financial Statements of Arrow for the year ended December 31, 2025 included in Arrow's Annual Report on Form 10-K for the year ended December 31, 2025 (the "2025 Form 10-K"). Accounting Standards Pending Adoption ASU No. 2024-03, "Income Statement - Reporting Comprehensive Income-Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses", requires new financial statement disclosures, disaggregating information for certain expense captions presented on the face of the income statements, including employee compensation, depreciation, and intangible asset amortization. Arrow is required to adopt this ASU prospectively for annual periods beginning after December 15, 2026, and interim periods beginning after December 15, 2027. Early adoption is permitted. Arrow is currently evaluating the potential impact of ASU 2024-03 on our Consolidated Financial Statements. Other ASUs issued but not effective until after March 31, 2026, are not expected to have a material effect on the Company’s consolidated financial position, annual results of operations and/or cash flows. 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 credit losses, the evaluation of 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 credit losses. In connection with the determination of the allowance for credit losses, management obtains appraisals for properties. The allowance for credit losses is management’s best estimate of expected credit losses as of the balance sheet date. While management uses available information to recognize losses on loans, future adjustments to the allowance for credit losses may be necessary based on changes in economic conditions. Allowance for Credit Losses – Loans Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (CECL) approach requires an estimate of the credit losses expected over the life of a loan (or pool of loans). The allowance for credit losses is a valuation account that is deducted from, or added to, the loans’ amortized cost basis to present the net lifetime amount expected to be collected on the loans. Credit losses are charged off against the allowance when management believes a loan balance to be uncollectible. Expected recoveries do not exceed the aggregate of amounts previously charged off and expected to be charged off. Management estimates the allowance using relevant available information from internal and external sources related to past events, current conditions, and a reasonable and supportable single economic forecast. Historical credit loss experience provides the basis for the estimation of expected credit losses. Arrow's historical loss experience is supplemented with peer information when there is insufficient loss data for Arrow. Peer selection is based on a review of institutions with comparable loss experience as well as loan yield, bank size, portfolio concentration and geography. Adjustments to historical loss information are made for differences in current loan-specific risk characteristics such as differences in credit concentrations, delinquency level, collateral values and underwriting standards as well as changes in economic conditions or other relevant factors. Management judgment is required at each point in the measurement process. Portfolio segment is defined as the level at which an entity develops and documents a systematic methodology to determine its allowance for credit losses. Management developed portfolio segments for estimating loss based on type of borrower and collateral as follows: Commercial Loans Commercial Real Estate Loans Consumer Loans Residential Loans Further details related to loan portfolio segments are included in Note 4. Loans to the Consolidated Financial Statements of this Form 10-Q. Arrow utilized regression analyses of peer data where observed credit losses and selected economic factors were utilized to determine suitable loss drivers for modeling lifetime probability of default (PD) rates. Arrow uses the discounted cash flow (DCF) method to estimate expected credit losses for the commercial, commercial real estate, and residential segments. For each of these loan segments, Arrow generates cash flow projections at the instrument level wherein payment expectations are adjusted for estimated prepayment speed, curtailments, time to recovery, PD, and segment-specific loss given default (LGD) risk factors. The modeling of expected prepayment speeds, curtailment rates, and time to recovery are based on historical internal data and adjusted, if necessary, based on the reasonable and supportable forecast of economic conditions. For the loan segments utilizing the DCF method (commercial, commercial real estate, and residential) management utilizes externally developed economic forecast of the following economic factors as loss drivers: national unemployment, gross domestic product and Case-Shiller U.S. National Home Price Index (HPI). The economic forecast is applied over a reasonable and supportable forecast period. Arrow utilizes a six quarter reasonable and supportable forecast period with an eight quarter reversion to the historic mean on a straight-line basis. The combination of adjustments for credit expectations (default and loss) and timing expectations (prepayment, curtailment, and time to recovery) produces an expected cash flow stream at the instrument level. Instrument effective yield is calculated, net of the impacts of prepayment assumptions, and the instrument expected cash flows are then discounted at that effective yield to produce an instrument-level net present value of expected cash flows (NPV). An allowance for credit loss is established for the difference between the instrument’s NPV and amortized cost basis. Arrow uses the vintage analysis method to estimate expected credit losses for the consumer loan segment. The vintage method was selected since the loans within the consumer loan segment are homogeneous, not just by risk characteristic, but by loan structure. Under the vintage analysis method, a loss rate is calculated based on the quarterly net charge-offs to the outstanding loan balance for each vintage year over the lookback period. Once this periodic loss rate is calculated for each quarter in the lookback period, the periodic rates are averaged into the loss rate. The loss rate is then applied to the outstanding loan balances based on the loan's vintage year. Arrow maintains, over the life of the loan, the loss curve by vintage year. If estimated losses computed by the vintage method need to be adjusted based on current conditions and the reasonable and supportable economic forecast, these adjustments would be incorporated over a six quarter reasonable and supportable forecast period, reverting to historical losses using a straight-line method over an eight quarter period. Arrow considers the need to qualitatively adjust expected credit loss estimates for information not already captured in the loss estimation process. These qualitative factor adjustments may increase or decrease management’s estimate of expected credit losses. Adjustments are not made for information that has already been considered and included in the loss estimation process. Arrow considers the qualitative factors that are relevant to Arrow as of the reporting date, which may include, but are not limited to the following factors: •The nature and volume of Arrow's financial assets; •The existence, growth, and effect of any concentrations of credit; •The volume and severity of past due loans, the volume of nonaccrual loans, and the volume and severity of adversely classified or graded loans; •The value of the underlying collateral for loans that are not collateral-dependent; •Arrow's lending policies and procedures, including changes in underwriting standards and practices for collections, write-offs, and recoveries; •The quality of Arrow's loan review function; •The experience, ability, and depth of Arrow's lending, investment, collection, and other relevant management/staff; •The effect of other external factors such as the regulatory, legal and technological environments; competition; and events such as natural disasters; •Actual and expected changes in international, national, regional, and local economic and business conditions and developments in which the institution operates that affect the collectability of financial assets; and •Other qualitative factors not reflected in quantitative loss rate calculations. All loans that exceed $250 thousand which are on nonaccrual, are evaluated on an individual basis. For collateral dependent financial assets where Arrow has determined that foreclosure of the collateral is probable, or where the borrower is experiencing financial difficulty and Arrow expects repayment of the financial asset to be provided substantially through the sale of the collateral, Arrow has elected to measure the allowance for credit loss as the difference between the fair value of the collateral less cost to sell, and the amortized cost basis of the asset as of the measurement date. In the event the repayment of a collateral dependent financial asset is expected to be provided substantially through the operation of the collateral, Arrow will use fair value of the collateral at the reporting date when recording the net carrying amount of the asset and determining the allowance for credit losses. When repayment is expected to be from the sale of the collateral, expected credit losses are calculated as the amount by which the amortized cost basis of the financial asset exceeds the fair value of the underlying collateral less estimated cost to sell. The allowance for credit losses may be zero if the fair value of the collateral at the measurement date exceeds the amortized cost basis of the financial asset. Arrow evaluates whether a modification represents a new loan or a continuation of an existing loan, consistent with the current GAAP treatment for other loan modifications. In addition, Arrow evaluates and if necessary, discloses if loan modifications made to borrowers experiencing financial difficulty contain a financial concession Estimated Credit Losses on Off-Balance Sheet Credit Exposures Recognized as Other Liabilities - Arrow estimates expected credit losses over the contractual period in which Arrow has exposure to credit risk via a contractual obligation to extend credit, unless that obligation is unconditionally cancellable by Arrow. The allowance for credit losses on off-balance sheet credit exposures recognized in other liabilities, is adjusted as an expense in other non-interest expense. The estimate includes consideration of the likelihood that funding will occur and an estimate of expected credit losses on commitments expected to be funded over their estimated lives. Estimating credit losses on unfunded commitments requires Arrow to consider the following categories of off-balance sheet credit exposure: unfunded commitments to extend credit, unfunded lines of credit, and standby letters of credit. Each of these unfunded commitments is then analyzed for a probability of funding to calculate a probable funding amount. The life of loan loss factor by related portfolio segment from the loan allowance for credit loss calculation is then applied to the probable funding amount to calculate the estimated credit losses on off-balance sheet credit exposures recognized as other liabilities.

The accompanying unaudited interim Consolidated Financial Statements contain all of the adjustments necessary to present fairly the financial position as of March 31, 2026 and December 31, 2025; the results of operations for the three month periods ended March 31, 2026 and 2025; the consolidated statements of comprehensive income for the three month periods ended March 31, 2026 and 2025; the changes in stockholders' equity for the three month periods ended March 31, 2026 and 2025; and the cash flows for the three month periods ended March 31, 2026 and 2025. All such adjustments are of a normal recurring nature. The unaudited interim Consolidated Financial Statements should be read in conjunction with the audited annual Consolidated Financial Statements of Arrow for the year ended December 31, 2025 included in Arrow's Annual Report on Form 10-K for the year ended December 31, 2025 (the "2025 Form 10-K").

ASU No. 2024-03, "Income Statement - Reporting Comprehensive Income-Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses", requires new financial statement disclosures, disaggregating information for certain expense captions presented on the face of the income statements, including employee compensation, depreciation, and intangible asset amortization. Arrow is required to adopt this ASU prospectively for annual periods beginning after December 15, 2026, and interim periods beginning after December 15, 2027. Early adoption is permitted. Arrow is currently evaluating the potential impact of ASU 2024-03 on our Consolidated Financial Statements.

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 credit losses, the evaluation of 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 credit losses. In connection with the determination of the allowance for credit losses, management obtains appraisals for properties. The allowance for credit losses is management’s best estimate of expected credit losses as of the balance sheet date. While management uses available information to recognize losses on loans, future adjustments to the allowance for credit losses may be necessary based on changes in economic conditions.

Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (CECL) approach requires an estimate of the credit losses expected over the life of a loan (or pool of loans). The allowance for credit losses is a valuation account that is deducted from, or added to, the loans’ amortized cost basis to present the net lifetime amount expected to be collected on the loans. Credit losses are charged off against the allowance when management believes a loan balance to be uncollectible. Expected recoveries do not exceed the aggregate of amounts previously charged off and expected to be charged off.

Management estimates the allowance using relevant available information from internal and external sources related to past events, current conditions, and a reasonable and supportable single economic forecast. Historical credit loss experience provides the basis for the estimation of expected credit losses. Arrow's historical loss experience is supplemented with peer information when there is insufficient loss data for Arrow. Peer selection is based on a review of institutions with comparable loss experience as well as loan yield, bank size, portfolio concentration and geography. Adjustments to historical loss information are made for differences in current loan-specific risk characteristics such as differences in credit concentrations, delinquency level, collateral values and underwriting standards as well as changes in economic conditions or other relevant factors. Management judgment is required at each point in the measurement process.

Portfolio segment is defined as the level at which an entity develops and documents a systematic methodology to determine its allowance for credit losses. Management developed portfolio segments for estimating loss based on type of borrower and collateral as follows:

Arrow utilized regression analyses of peer data where observed credit losses and selected economic factors were utilized to determine suitable loss drivers for modeling lifetime probability of default (PD) rates. Arrow uses the discounted cash flow (DCF) method to estimate expected credit losses for the commercial, commercial real estate, and residential segments. For each of these loan segments, Arrow generates cash flow projections at the instrument level wherein payment expectations are adjusted for estimated prepayment speed, curtailments, time to recovery, PD, and segment-specific loss given default (LGD) risk factors. The modeling of expected prepayment speeds, curtailment rates, and time to recovery are based on historical internal data and adjusted, if necessary, based on the reasonable and supportable forecast of economic conditions.

For the loan segments utilizing the DCF method (commercial, commercial real estate, and residential) management utilizes externally developed economic forecast of the following economic factors as loss drivers: national unemployment, gross domestic product and Case-Shiller U.S. National Home Price Index (HPI). The economic forecast is applied over a reasonable and supportable forecast period. Arrow utilizes a six quarter reasonable and supportable forecast period with an eight quarter reversion to the historic mean on a straight-line basis.

The combination of adjustments for credit expectations (default and loss) and timing expectations (prepayment, curtailment, and time to recovery) produces an expected cash flow stream at the instrument level. Instrument effective yield is calculated, net of the impacts of prepayment assumptions, and the instrument expected cash flows are then discounted at that effective yield to produce an instrument-level net present value of expected cash flows (NPV). An allowance for credit loss is established for the difference between the instrument’s NPV and amortized cost basis.

Arrow uses the vintage analysis method to estimate expected credit losses for the consumer loan segment. The vintage method was selected since the loans within the consumer loan segment are homogeneous, not just by risk characteristic, but by loan structure. Under the vintage analysis method, a loss rate is calculated based on the quarterly net charge-offs to the outstanding loan balance for each vintage year over the lookback period. Once this periodic loss rate is calculated for each quarter in the lookback period, the periodic rates are averaged into the loss rate. The loss rate is then applied to the outstanding loan balances based on the loan's vintage year. Arrow maintains, over the life of the loan, the loss curve by vintage year. If estimated losses computed by the vintage method need to be adjusted based on current conditions and the reasonable and supportable economic forecast, these adjustments would be incorporated over a six quarter reasonable and supportable forecast period, reverting to historical losses using a straight-line method over an eight quarter period.

Arrow considers the need to qualitatively adjust expected credit loss estimates for information not already captured in the loss estimation process. These qualitative factor adjustments may increase or decrease management’s estimate of expected credit losses. Adjustments are not made for information that has already been considered and included in the loss estimation process.

All loans that exceed $250 thousand which are on nonaccrual, are evaluated on an individual basis. For collateral dependent financial assets where Arrow has determined that foreclosure of the collateral is probable, or where the borrower is experiencing financial difficulty and Arrow expects repayment of the financial asset to be provided substantially through the sale of the collateral, Arrow has elected to measure the allowance for credit loss as the difference between the fair value of the collateral less cost to sell, and the amortized cost basis of the asset as of the measurement date. In the event the repayment of a collateral dependent financial asset is expected to be provided substantially through the operation of the collateral, Arrow will use fair value of the collateral at the reporting date when recording the net carrying amount of the asset and determining the allowance for credit losses. When repayment is expected to be from the sale of the collateral, expected credit losses are calculated as the amount by which the amortized cost basis of the financial asset exceeds the fair value of the underlying collateral less estimated cost to sell. The allowance for credit losses may be zero if the fair value of the collateral at the measurement date exceeds the amortized cost basis of the financial asset.

Arrow evaluates whether a modification represents a new loan or a continuation of an existing loan, consistent with the current GAAP treatment for other loan modifications. In addition, Arrow evaluates and if necessary, discloses if loan modifications made to borrowers experiencing financial difficulty contain a financial concession

Estimated Credit Losses on Off-Balance Sheet Credit Exposures Recognized as Other Liabilities - Arrow estimates expected credit losses over the contractual period in which Arrow has exposure to credit risk via a contractual obligation to extend credit, unless that obligation is unconditionally cancellable by Arrow. The allowance for credit losses on off-balance sheet credit exposures recognized in other liabilities, is adjusted as an expense in other non-interest expense. The estimate includes consideration of the likelihood that funding will occur and an estimate of expected credit losses on commitments expected to be funded over their estimated lives. Estimating credit losses on unfunded commitments requires Arrow to consider the following categories of off-balance sheet credit exposure: unfunded commitments to extend credit, unfunded lines of credit, and standby letters of credit. Each of these unfunded commitments is then analyzed for a probability of funding to calculate a probable funding amount. The life of loan loss factor by related portfolio segment from the loan allowance for credit loss calculation is then applied to the probable funding amount to calculate the estimated credit losses on off-balance sheet credit exposures recognized as other liabilities.