Consolidated Statements of Income (Unaudited) [Abstract] Total interest and dividends on securities available for sale Total interest on held to maturity securities Total interest income Total interest expense Net interest income Net interest income after provision for credit losses Total noninterest income Total non-interest income Total noninterest expenses Income before taxes Net income Net income Net income (in Dollars) Consolidated Statements of Comprehensive Income (Unaudited) [Abstract] Net unrealized (loss) gain on securities available for sale, net of tax Amortization of net actuarial gain and prior service cost on pension and postretirement plans, net of tax Other comprehensive (loss) income, net of tax Other comprehensive income (loss), net of tax Comprehensive income Consolidated Statements of Financial Condition (Unaudited) [Abstract] Total cash and cash equivalents Cash and cash equivalents Net loans Carrying balances of loans Total assets Total deposits Total liabilities Total shareholders’ equity Balance Balance Total liabilities and shareholders’ equity Consolidated Statements of Changes in Shareholders' Equity (Unaudited) [Abstract] Equity Components [Axis] Consolidated Statements of Cash Flows (Unaudited) [Abstract] Total adjustments Net cash provided by operating activities Net cash (used in) provided by investing activities Net cash provided by financing activities Net increase in cash and cash equivalents Cash and cash equivalents at beginning of period Cash and cash equivalents at end of period Financial Statement Presentation [Abstract] Earnings Per Share [Abstract] Net income per share: Weighted average common shares including potential dilutive shares (in Shares) Benefit Plans [Abstract] Net periodic benefit Retirement Plan Type [Axis] Investment Securities [Abstract] Financial Instrument [Axis] Amortized Cost Debt Security Category [Axis] Total securities available for sale Securities available for sale Fair Value Total - Fair Value Total - Gross Unrealized Loss Amortized Cost Held to maturity securities ($4,134 and $4,389 fair value at March 31, 2026 and December 31, 2025, respectively) Amortized Cost More than 12 months - Gross Unrecognized Loss Gross Unrecognized Losses Gross Unrecognized Losses Loan Portfolio and Allowance for Credit Losses [Abstract] Financing Receivable Portfolio Segment [Axis] Class of Financing Receivable [Axis] Geographical [Axis] Balance at beginning of period Balance at end of period Total ending allowance balance Less: Allowance for credit losses on loans Type of Borrower [Axis] Internal Credit Assessment [Axis] Total loans Loans, net of deferred costs Total loans, net Current-period Gross writeoffs Total loan charge offs Financial Instrument Performance Status [Axis] Financial Asset, Aging [Axis] Collateral Held [Axis] Loan Restructuring Modification [Axis] Fair Value of Financial Instruments [Abstract] Measurement Basis [Axis] Measurement Frequency [Axis] Fair Value Hierarchy and NAV [Axis] Valuation Approach and Technique [Axis] Measurement Input Type [Axis] Statistical Measurement [Axis] Accumulated Other Comprehensive Income (Loss) [Abstract] Reclassification out of Accumulated Other Comprehensive Income [Axis] Revenue from Contracts with Customers [Abstract] Product and Service [Axis] Operating Leases [Abstract] Total Lease costs Total lease payments Regulatory Capital Requirements [Abstract] Consolidated Entities [Axis] Segment Reporting [Abstract] New Accounting Pronouncements [Abstract] Document Type Document Quarterly Report Document Period End Date Document Fiscal Year Focus Document Transition Report Entity File Number Entity Registrant Name Entity Incorporation, State or Country Code Entity Tax Identification Number Entity Address, Address Line One Entity Address, City or Town Entity Address, State or Province Entity Address, Postal Zip Code City Area Code Local Phone Number Title of 12(b) Security Trading Symbol Security Exchange Name Entity Current Reporting Status Entity Interactive Data Current Entity Filer Category Entity Small Business Entity Emerging Growth Company Entity Shell Company Entity Common Stock, Shares Outstanding Entity Central Index Key Amendment Flag Document Fiscal Period Focus Current Fiscal Year End Date Interest and dividend income: Interest and fees on loans Interest and dividends on securities available for sale: U. S. government sponsored enterprises State and political subdivisions Mortgage-backed securities and collateralized mortgage obligations - residential Corporate bonds Small Business Administration-guaranteed participation securities Other securities Interest on held to maturity securities: Mortgage-backed securities and collateralized mortgage obligations-residential Federal Home Loan Bank stock Interest on federal funds sold and other short-term investments Interest expense: Interest on deposits: Interest-bearing checking Savings accounts Money market deposit accounts Time deposits Interest on short-term borrowings Provision for credit losses Provision (benefit) for credit losses Noninterest income: Non-interest income Trustco financial services income Fees for services to customers Other Noninterest expenses: Salaries and employee benefits Net occupancy expense Equipment expense Professional services Outsourced services Advertising expense FDIC and other insurance Other real estate expense, net Other Income taxes Income tax benefit - Basic (in Dollars per share) Basic EPS (in Dollars per share) - Diluted (in Dollars per share) Diluted EPS (in Dollars per share) Net unrealized holding (loss) gain on securities available for sale Amortization of prior service cost Tax effect Change in deferred tax effect of amortization of net actuarial gain postretirement benefit plans ASSETS: Cash and due from banks Federal funds sold and other short term investments Held to maturity securities, fair value Fair Value Federal Home Loan Bank stock Bank premises and equipment, net Operating lease right-of-use assets Other assets LIABILITIES: Deposits: Demand Interest-bearing checking Savings accounts Money market deposit accounts Time deposits Short-term borrowings Operating lease liabilities Present value of lease liabilities Accrued expenses and other liabilities SHAREHOLDERS’ EQUITY: Capital stock par value $1.00; 30,000,000 shares authorized; 20,118,509 shares issued at both March 31, 2026 and December 31, 2025, 17,506,881 and 18,029,107 shares outstanding at March 31, 2026 and December 31, 2025, respectively Capital stock, par value (in Dollars per share) Capital stock, shares authorized (in Shares) Capital stock, shares issued (in Shares) Capital stock, shares outstanding (in Shares) Surplus Undivided profits Accumulated other comprehensive income, net of tax Treasury stock, at cost (in Shares) Stock Based Compensation Expense Cash dividend declared (in Dollars per share) Purchase of treasury stock (in Shares)