Stockholders Equity Parenthetical [Abstract] Stockholders Equity Parenthetical [Abstract] Statement [Table] Statement [Table] Statement, Scenario [Axis] Statement, Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Report Date [Axis] Report Date [Axis] Financial Statements Date [Domain] Financial Statements Date [Domain] Statement, Equity Components [Axis] Statement, Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Adjustments for Change in Accounting Principle [Axis] Adjustments for Change in Accounting Principle [Axis] Adjustments for Change in Accounting Principle [Domain] Adjustments for Change in Accounting Principle [Domain] Adjustments for Error Corrections [Axis] Adjustments for Error Corrections [Axis] Adjustments for Error Correction [Domain] Adjustments for Error Correction [Domain] Statement [Line Items] Statement [Line Items] Cash Dividends Paid, per Share Common Stock, Dividends, Per Share, Cash Paid Stock Dividends - Shares Stock Dividends, Shares Stock Options Exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Shares Issued Under Directors Stock Plan Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures Shares Issued Under the Employee Stock Purchase Plan Stock Issued During Period, Shares, Employee Stock Purchase Plans Shares Issued for Dividend Reinvestment Plans Stock Issued During Period, Shares, Dividend Reinvestment Plan Purchase of Treasury Stock Treasury Stock, Shares, Acquired Acquisition of Subsidiary Stock Issued During Period, Shares, Acquisitions Acquisition by ESOP of Arrow Stock Acquisition By Esop Of Arrow Stock, Share -- None. No documentation exists for this element. -- Allocation of ESOP Stock Stock Issued During Period, Shares, Employee Stock Ownership Plan Document and Entity Informantion [Abstract] Document and Entity Informantion [Abstract] Entities [Table] Entities [Table] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Entity Information [Line Items] Entity Information [Line Items] Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Document Type Document Type Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Amendment Flag Amendment Flag Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Entity Well-known Seasoned Filer Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Voluntary Filers Entity Current Reporting Status Entity Current Reporting Status Entity Public Float Entity Public Float Balance Sheet Parenthetical [Abstract] Balance Sheet Parenthetical [Abstract] Securities Held-to-Maturity, at Fair Value Held-to-maturity Securities, Fair Value Preferred Stock, Par Value Preferred Stock, Par or Stated Value Per Share Preferred Stock, Shares Authorized Preferred Stock, Shares Authorized Common Stock, Par Value Common Stock, Par or Stated Value Per Share Common Stock, Shares Authorized Common Stock, Shares Authorized Common Stock, Shares Issued Common Stock, Shares, Issued Unallocated ESOP Shares - Shares Employee Stock Ownership Plan (ESOP), Number of Committed-to-be-Released Shares Treasury Stock, Shares Treasury Stock, Shares Compensation Related Costs, Retirement Benefits [Abstract] -- None. No documentation exists for this element. -- Pension and Other Postretirement Benefits Disclosure [Text Block] Pension and Other Postretirement Benefits Disclosure [Text Block] Compensation Related Costs, Share Based Payments [Abstract] -- None. No documentation exists for this element. -- Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Guaranteed Preferred Beneficial Interests in Corporation's Junior Subordinated Debentures [Abstract] Guaranteed Preferred Beneficial Interests in Corporation's Junior Subordinated Debentures [Abstract] Long-term Debt [Text Block] Long-term Debt [Text Block] FHLBNY Advances [Abstract] FHLBNY Advances [Abstract] Federal Home Loan Bank Advances, Disclosure [Text Block] Federal Home Loan Bank Advances, Disclosure [Text Block] Consolidated Statements of Comprehensive Income [Abstract] Consolidated Statements of Comprehensive Income [Abstract] Net Income Net Income (Loss) Attributable to Parent Other Comprehensive Income (Loss), Net of Tax: Other Comprehensive Income (Loss), Net of Tax [Abstract] Unrealized Securities Holding Gains Arising During the Period Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax Reclassification Adjustment for Net Securities Gains Included in Net Income, Net of Tax Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Net of Tax Reclassification Adjustment for Other-Than-Temporary Impairment Other Comprehensive Income (Loss), Reclassification Adjustment for Write-down of Securities Included in Net Income, Net of Tax Net Retirement Plan (Loss) Gain Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, before Tax Net Retirement Plan Prior Service (Cost) Credit Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Prior Service Costs (Credit) Arising During Period, Net of Tax Amortization of Net Retirement Plan Actuarial Loss Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax Accretion of Net Retirement Plan Prior Service Credit Other Comprehensive Income (Loss), Amortization, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost (Credit) Recognized in Net Periodic Benefit Cost, before Tax Other Comprehensive (Loss) Income Other Comprehensive Income (Loss), Net of Tax Comprehensive Income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Accounting Policies [Abstract] Significant Accounting Policies [Text Block] Significant Accounting Policies [Text Block] Regulatory Matters [Abstract] Regulatory Matters [Abstract] Regulatory Capital Requirements under Banking Regulations [Text Block] Regulatory Capital Requirements under Banking Regulations [Text Block] Other Operating Expense [Abstract] Other Operating Expense [Abstract] Schedule of Other Operating Cost and Expense, by Component [Table Text Block] Schedule of Other Operating Cost and Expense, by Component [Table Text Block] Concentrations of Credit Risk [Abstract] Concentrations of Credit Risk [Abstract] Concentration Risk Disclosure [Text Block] Concentration Risk Disclosure [Text Block] Receivables, Loans, Notes Receivable, and Others [Abstract] -- None. No documentation exists for this element. -- Financing Receivables [Text Block] Financing Receivables [Text Block] Statement of Cash Flows [Abstract] Cash Flows from Operating Activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Provision for Loan Losses Provision for Loan and Lease Losses Depreciation and Amortization Depreciation, Depletion and Amortization, Nonproduction Allocation of ESOP Stock Allocated Share-based Compensation Expense Gains on the Sale of Securities Available-for-Sale Available-for-sale Securities, Gross Realized Gains Losses on the Sale of Securities Available-for-Sale Available-for-sale Securities, Gross Realized Losses, Excluding Other than Temporary Impairments Other Than Temporary Impairment Marketable Securities, Realized Loss, Other than Temporary Impairments, Amount Loans Originated and Held-for-Sale Payments for Origination of Mortgage Loans Held-for-sale Proceeds from the Sale of Loans Held-for-Sale Proceeds from Sale of Loans Held-for-sale Net Gains on the Sale of Loans Gain (Loss) on Sale of Loans and Leases Net Loss (Gains) on the Sale of Premises and Equipment, Other Real Estate Owned and Repossessed Assets Gain (Loss) on Sale of Other Assets Contributions to Pension Plans Defined Benefit Plan, Contributions by Employer Deferred Income Tax Expense (Benefit) Deferred Income Tax Expense (Benefit) Shares Issued Under the Directors' Stock Plan Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures Stock-Based Compensation Expense Share-based Compensation Net Decrease (Increase) in Other Assets Increase (Decrease) in Other Operating Assets Net (Decrease) Increase in Other Liabilities Increase (Decrease) in Other Operating Liabilities Net Cash Provided By Operating Activities Net Cash Provided by (Used in) Operating Activities Cash Flows from Investing Activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Proceeds from the Sale of Securities Available-for-Sale Proceeds from Sale of Available-for-sale Securities Proceeds from the Maturities and Calls of Securities Available-for-Sale Proceeds from Maturities, Prepayments and Calls of Available-for-sale Securities Purchases of Securities Available-for-Sale Payments to Acquire Available-for-sale Securities Proceeds from the Maturities and Calls of Securities Held-to-Maturity Proceeds from Maturities, Prepayments and Calls of Held-to-maturity Securities Purchases of Securities Held-to-Maturity Payments to Acquire Held-to-maturity Securities Net Decrease (Increase) in Loans Payments for (Proceeds from) Loans and Leases Proceeds from the Sales of Premises and Equipment, Other Real Estate Owned and Repossessed Assets Proceeds from Sale of Other Property, Plant, and Equipment Purchases of Premises and Equipment Payments to Acquire Property, Plant, and Equipment Cash Paid for Subsidiaries Payments to Acquire Interest in Subsidiaries and Affiliates Net Decrease in Other Investments Payments for (Proceeds from) Other Investing Activities Purchase of Bank Owned Life Insurance Payments to Acquire Life Insurance Policies Net Cash Used In Investing Activities Net Cash Provided by (Used in) Investing Activities Cash Flows from Financing Activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Net Increase in Deposits Increase (Decrease) in Customer Deposits Net (Decrease) Increase in Short-Term Borrowings Proceeds from (Repayments of) Short-term Debt Federal Home Loan Bank Advances Proceeds from Federal Home Loan Bank Advances Federal Home Loan Bank Repayments Repayments of Federal Home Loan Bank Borrowings Purchases of Treasury Stock Treasury Stock, Value, Acquired, Cost Method Stock Options Exercised Proceeds from Stock Options Exercised Shares Issued Under the Employee Stock Purchase Plan Stock Issued During Period, Value, Employee Stock Purchase Plan Tax Benefit from Exercise of Stock Options Tax Benefit from Stock Options Exercised Shares Issued for Dividend Reinvestment Plans Stock Issued During Period, Value, Dividend Reinvestment Plan Acquisition by ESOP of Arrow Stock Acquisition by Esop of Arrow Stock -- None. No documentation exists for this element. -- Cash Dividends Paid Dividends, Common Stock, Cash Net Cash Provided By Financing Activities Net Cash Provided by (Used in) Financing Activities Net Increase (Decrease) in Cash and Cash Equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and Cash Equivalents at Beginning of Year Cash and Cash Equivalents, at Carrying Value Cash and Cash Equivalents at End of Year Supplemental Disclosures to Statements of Cash Flow Information: Supplemental Cash Flow Information [Abstract] Interest on Deposits and Borrowings Interest Paid Income Taxes Income Taxes Paid Non-cash Investing and Financing Activities: Noncash Investing and Financing Items [Abstract] Transfer of Loans to Other Real Estate Owned and Repossessed Assets Transfer of Other Real Estate Shares Issued for Acquisition of Subsidiary Stock Issued During Period, Value, Acquisitions Fair Value of Assets from Acquisition of Subsidiary Noncash or Part Noncash Acquisition, Other Assets Acquired Fair Value of Liabilities from Acquisition of Subsidiary Noncash or Part Noncash Acquisition, Other Liabilities Assumed Time Deposits [Abstract] Deposit Liabilities Disclosures [Text Block] Deposit Liabilities Disclosures [Text Block] Parent Only Financial Information [Abstract] Parent Only Financial Information [Abstract] Condensed Financial Information of Parent Company Only Disclosure [Text Block] Condensed Financial Information of Parent Company Only Disclosure [Text Block] Comprehensive Income [Abstract] -- None. No documentation exists for this element. -- Other Comprehensive Income, Noncontrolling Interest [Text Block] Other Comprehensive Income, Noncontrolling Interest [Text Block] Earnings Per Share [Abstract] Earnings Per Share [Text Block] Earnings Per Share [Text Block] Short-term Debt [Abstract] Short-term Debt [Text Block] Short-term Debt [Text Block] Property, Plant and Equipment, Other, Net [Abstract] Property, Plant and Equipment Disclosure [Text Block] Property, Plant and Equipment Disclosure [Text Block] Other Employee Benefit Plans [Abstract] Other Employee Benefit Plans [Abstract] Compensation Related Costs, General [Text Block] Compensation Related Costs, General [Text Block] Income Statement [Abstract] INTEREST AND DIVIDEND INCOME Investment Income, Interest and Dividend [Abstract] Interest and Fees on Loans Interest and Fee Income, Loans and Leases Interest on Deposits at Banks Interest Income, Domestic Deposits Interest and Dividends on Investment Securities: Interest and Dividend Income, Securities, by Taxable Status [Abstract] Fully Taxable Interest Income, Securities, Taxable Exempt from Federal Taxes Interest Income, Securities, Tax Exempt Total Interest and Dividend Income Investment Income, Interest and Dividend INTEREST EXPENSE Interest Expense [Abstract] NOW Accounts Interest Expense, Negotiable Order of Withdrawal (NOW) Deposits Savings Deposits Interest Expense, Savings Deposits Time Deposits of $100,000 or More Interest Expense, Time Deposits, $100,000 or More Other Time Deposits Interest Expense, Time Deposits, Less than $100,000 Federal Funds Purchased and Securities Sold Under Agreements to Repurchase Interest Expense, Federal Funds Purchased and Securities Sold under Agreements to Repurchase Federal Home Loan Bank Advances Interest Expense, Federal Home Loan Bank and Federal Reserve Bank Advances, Long-term Junior Subordinated Obligations Issued to Unconsolidated Subsidary Trusts Interest Expense, Junior Subordinated Debentures Total Interest Expense Interest Expense NET INTEREST INCOME Interest Income (Expense), Net NET INTEREST INCOME AFTER PROVISION FOR LOAN LOSSES Net Interest Income (Loss) after Provision for Loan Losses NONINTEREST INCOME Noninterest Income [Abstract] Income from Fiduciary Activities Fees and Commissions, Fiduciary and Trust Activities Fees for Other Services to Customers Fees and Commissions, Depositor Accounts Insurance Commissions Insurance Commissions and Fees Net Gains on Securities Transactions Gain (Loss) on Sale of Securities, Net Net Gains on Sale of Loans Gain (Loss) on Sales of Loans, Net Other-Than-Temporary Impairment on Investment Securities Other than Temporary Impairment Losses, Investments Net Gain on Sale of Merchange Bank Card Processing Net Gain on Sale of Merchange Bank Card Processing Net Gain on Sale of Merchange Bank Card Processing Other Operating Income Other Operating Income Total Noninterest Income Noninterest Income NONINTEREST EXPENSE Noninterest Expense [Abstract] Salaries and Employee Benefits Labor and Related Expense Occupancy Expense, Net Occupancy, Net FDIC Assessments Federal Deposit Insurance Corporation Premium Expense Prepayment Penalty on FHLB Advances Prepayment Penalty on Fhlb Advances -- None. No documentation exists for this element. -- Other Operating Expense Other Noninterest Expense Total Noninterest Expense Noninterest Expense INCOME BEFORE PROVISION FOR INCOME TAXES Income (Loss) from Continuing Operations before Income Taxes, Domestic Provision for Income Taxes Income Tax Expense (Benefit) Net Income Average Shares Outstanding: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Basic Weighted Average Number of Shares Outstanding, Basic Diluted Weighted Average Number of Shares Outstanding, Diluted Earnings Per Share Basic Earnings Earnings Per Share, Basic Diluted Earnings Earnings Per Share, Diluted Note 21. Fair Value of Financial Instruments [Abstract] Note 21. Fair Value of Financial Instruments [Abstract] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Table] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Table] Fair Value by Measurement Frequency [Axis] Fair Value by Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value Disclosures [Text Block] Fair Value Disclosures [Text Block] Statement of Financial Position [Abstract] ASSETS Assets [Abstract] Cash and Due from Banks Cash and Due from Banks Interest-Bearing Deposits at Banks Interest-bearing Deposits in Banks and Other Financial Institutions Investment Securities: Investments, Debt and Equity Securities [Abstract] Available-for-Sale Available-for-sale Securities Held-to-Maturity Held-to-maturity Securities Other Investments Other Investments Loans Loans and Leases Receivable, Gross, Carrying Amount Allowance for Loan Losses Loans and Leases Receivable, Allowance Net Loans Loans and Leases Receivable, Net Reported Amount Premises and Equipment, Net Property, Plant and Equipment, Net Other Real Estate and Repossessed Assets, Net Other Real Estate and Foreclosed Assets Goodwill Goodwill Other Intangible Assets, Net Other Intangible Assets, Net Accrued Interest Receivable Interest Receivable Other Assets Other Assets Total Assets Assets LIABILITIES Liabilities [Abstract] Noninterest-Bearing Deposits Noninterest-bearing Deposit Liabilities NOW Accounts Deposits, Negotiable Order of Withdrawal (NOW) Savings Deposits Deposits, Savings Deposits Time Deposits of $100,000 or More Time Deposits, $100,000 or More Other Time Deposits Time Deposits, Less than $100,000 Total Deposits Deposits Federal Funds Purchased and Securities Sold Under Agreements to Repurchase Federal Funds Purchased and Securities Sold under Agreements to Repurchase Other Short-Term Borrowings Other Short-term Borrowings Federal Home Loan Bank Overnight Advances Federal Home Loan Bank, Advances, Short-term Federal Home Loan Bank Advances Federal Home Loan Bank Advances Junior Subordinated Obligations Issued to Unconsolidated Subsidiary Trusts Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust Accrued Interest Payable Interest Payable Other Liabilities Other Liabilities Total Liabilities Liabilities STOCKHOLDERS' EQUITY Stockholders' Equity Attributable to Parent [Abstract] Preferred Stock Preferred Stock, Value, Issued Common Stock Common Stock, Value, Issued Additional Paid-in Capital Additional Paid in Capital Retained Earnings Retained Earnings (Accumulated Deficit) Unallocated ESOP Shares Unearned ESOP Shares Accumulated Other Comprehensive Loss Accumulated Other Comprehensive Income (Loss), Net of Tax Treasury Stock Treasury Stock, Value Total Stockholders' Equity Stockholders' Equity Attributable to Parent Total Liabilities and Stockholders' Equity Liabilities and Equity Lease Commitments [Abstract] Lease Commitments [Abstract] Leases of Lessee Disclosure [Text Block] Leases of Lessee Disclosure [Text Block] Cash and Cash Equivalents [Abstract] Cash and Cash Equivalents Disclosure [Text Block] Cash and Cash Equivalents Disclosure [Text Block] Guarantees [Abstract] Guarantees [Text Block] Guarantees [Text Block] Statement of Stockholders' Equity [Abstract] Common Stock Common Stock [Member] Additional Paid in Capital Additional Paid-in Capital [Member] Retained Earnings Retained Earnings [Member] Unallocated ESOP Shares Unallocated Esop Shares [Member] -- None. No documentation exists for this element. -- Accumulated Other Comprensive Income (Loss) Accumulated Net Unrealized Investment Gain (Loss) [Member] Treasury Stock Treasury Stock [Member] Stockholder's Equity Beginning Balance Other Comprehensive (Loss) Income 3% Stock Dividend Stock Issued During Period, Value, Stock Dividend Shares Issued Under the Directors' Stock Purchase Plan Proceeds from Stock Plans Tax Benefit for Disposition of Stock Options Employee Service Share-based Compensation, Tax Benefit Realized from Exercise of Stock Options Allocation of ESOP Stock Stock Issued During Period, Value, Employee Stock Ownership Plan Stockholder's Equity Ending Balance Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Other Intangible Assets [Abstract] Other Intangible Assets [Abstract] Intangible Assets Disclosure [Text Block] Intangible Assets Disclosure [Text Block] Income Taxes [Abstract] Income Taxes [Abstract] Income Tax Disclosure [Text Block] Income Tax Disclosure [Text Block]