Document And Entity Information Statistical Measurement [Axis] Note To Financial Statement Details Textual Note 3 - Securities Total provision for income taxes Note 4 - Loans Mortgage Banking [Member] us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardForfeited Restricted stock forfeited (in shares) ecd_NonRule10b51ArrTrmntdFlag Non-Rule 10b5-1 Arrangement Terminated [Flag] Note 5 - Financial Instruments and Fair Value Measurements ecd_NonRule10b51ArrAdoptedFlag Non-Rule 10b5-1 Arrangement Adopted [Flag] Note 6 - Earnings Per Share Debit Card [Member] Depreciation ovly_IncrementalCommonSharesAttributableToNonvestedRestrictedShares Effect of dilutive non-vested restricted shares (in shares) Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of non-vested restricted shares. Trading Arrangements, by Individual [Table] Note 3 - Securities - Amortized Cost and Estimated Fair Values of Debt Securities (Details) Deposit Account [Member] Restricted stock issued (in shares) Material Terms of Trading Arrangement [Text Block] Note 3 - Securities - Securities in a Continuous Loss Position (Details) Financial Instrument [Axis] Investment in Debt and Equity Securities and Other Trading Assets [Text Block] Note 3 - Securities - Maturity (Details) Note 4 - Loans - Loans (Details) us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax Available-for-sale securities, gross unrealized losses Minimum [Member] Note 4 - Loans - Nonaccrual Status (Details) Available-for-sale securities, gross unrealized gains Note 4 - Loans - Individual Evaluation Loans (Details) Statistical Measurement [Domain] Note 4 - Loans - Aging of Past Due Loans (Details) Maximum [Member] Note 4 - Loans - Credit Quality Indicators (Details) Note 4 - Loans - Allowance for Loan Losses (Details) (Decrease) increase in interest payable and other liabilities Note 4 - Loans - Changes in the Allowance, Off-balance-sheet Commitments (Details) Note 5 - Financial Instruments and Fair Value Measurements - Fair Value of Financial Instruments (Details) CASH FLOWS FROM OPERATING ACTIVITIES: Note 5 - Financial Instruments and Fair Value Measurements - Schedule of Recurring and Non-recurring Assets and Liabilities (Details) (Loss) gain on sales and calls of available-for-sale securities Amount of realized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) from sale and call of securities. CASH FLOWS FROM INVESTING ACTIVITIES: Note 6 - Earnings Per Share - Earnings Per Share (Details) us-gaap_NetCashProvidedByUsedInOperatingActivities Net cash provided by operating activities Notes To Financial Statements CASH FLOWS FROM FINANCING ACTIVITIES: Notes To Financial Statements [Abstract] us-gaap_NetCashProvidedByUsedInInvestingActivities Net cash used in investing activities us-gaap_NetCashProvidedByUsedInFinancingActivities Net cash provided by in financing activities us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt Purchases of available-for-sale securities us-gaap_IncreaseDecreaseInDeferredCharges Increase in deferred fees/costs, net Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Salaries and employee benefits Accounting Policies [Abstract] Interest receivable and other assets Accounting Standards Update and Change in Accounting Principle [Text Block] Financial Instruments [Domain] us-gaap_CommonStockDividendsPerShareDeclared Common Stock, Dividends, Per Share, Declared (in dollars per share) US States and Political Subdivisions Debt Securities [Member] Loans, net of allowance for credit losses of $12,910 and $12,381 at March 31, 2026 and December 31, 2025, respectively Net loans Asset Pledged as Collateral [Member] us-gaap_IncreaseDecreaseInAccruedInterestReceivableNet Increase in interest receivable us-gaap_PaymentsForProceedsFromLoansAndLeases Net increase in loans Measurement Input Type [Axis] Income Statement [Abstract] us-gaap_SharesOutstanding Balances (in shares) Balances (in shares) Available-for-sale securities, amortized cost Total, amortized cost Provision for off balance sheet commitments Available-for-sale securities, fair market value Securities - available for sale Total, fair value Decrease (increase) in deferred tax asset 12 months or more, fair value Individual evaluated loans Average amount of investment of individual evaluated loans. Net increase in time deposits Summary of Individual Evaluated Loans [Table Text Block] Tabular disclosure of individual evaluated loans. Less than 12 months, fair value Net income Net Income Net income Adjustments to reconcile net income to net cash provided by operating activities: us-gaap_Liabilities Total liabilities Financial Asset, Past Due [Member] us-gaap_LiabilitiesAndStockholdersEquity Liabilities and Equity Pledged Status [Domain] Measurement Input Type [Domain] us-gaap_InterestIncomeExpenseNet Net interest income Pledged Status [Axis] Unlikely to be Collected Financing Receivable [Member] us-gaap_ShareBasedCompensation Stock based compensation LIABILITIES AND SHAREHOLDERS’ EQUITY us-gaap_FinancingReceivableNonaccrualInterestIncome Financing Receivable, Nonaccrual, Interest Income Asset-Backed Securities [Member] Portion at Fair Value Measurement [Member] Reported Value Measurement [Member] Occupancy expenses us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS Other operating expenses Regulatory assessments us-gaap_CashAndCashEquivalentsFairValueDisclosure Cash and cash equivalents Estimate of Fair Value Measurement [Member] Earnings on cash surrender value of life insurance Earnings on cash surrender value of life insurance us-gaap_NoninterestIncome Total non-interest income Better Than Acceptable [Member] Represents risk assessment of better than acceptable. NON-INTEREST INCOME Exceptional [Member] Represents risk assessment of exceptional. us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations CASH AND CASH EQUIVALENTS, beginning of period CASH AND CASH EQUIVALENTS, end of period US Government Agencies Debt Securities [Member] Measurement Basis [Axis] Statement [Table] ovly_StockIssuedDuringPeriodValueRestrictedStockAwardSurrendered Restricted stock surrendered for tax withholding Value of stock related to Restricted Stock Awards Surrendered during the period. Debt Securities, Available-for-Sale, Allowance for Credit Loss [Table] ovly_FinancingReceivableLoantovalueOnRealEstateSecuredTransactions Financing Receivable, Loan-to-value on Real Estate Secured Transactions Percentage of loan to value on real estate secured transactions. Operating leases us-gaap_NoninterestIncomeOtherOperatingIncome Other Fair Value Hierarchy and NAV [Domain] Public Funds [Member] Represents public funds. Measurement Frequency [Domain] us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss U.S. agencies Collateral dependent loans Loans, net us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability Right-of-use asset obtained in exchange for new operating lease liability Statement of Financial Position [Abstract] U.S. agencies Mutual fund Securities - equity investments Equity Securities, FV-NI, Current Goodwill and other intangible assets, net Provision for (reversal of) credit losses us-gaap_FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal us-gaap_DividendsCommonStock Cash dividends declared Number of Securities Financing Receivable, Allowance for Credit Loss [Table Text Block] Multifamily [Member] Financing Receivable, Past Due [Table Text Block] Recoveries us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff Charge-offs Gross write offs Mutual Fund [Member] us-gaap_EquitySecuritiesFvNiRealizedGainLoss Equity Securities, FV-NI, Realized Gain (Loss) Financing Receivable Credit Quality Indicators [Table Text Block] Product and Service [Domain] Product and Service [Axis] Fair Value, Nonrecurring [Member] Fair Value, Recurring [Member] us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss Unrealized (gain) loss on equity securities Equity Securities, FV-NI, Unrealized Gain (Loss) Collateralized Mortgage Obligations [Member] us-gaap_IncreaseDecreaseInOtherOperatingAssets Decrease in other assets dei_DocumentType Document Type Commercial Real Estate [Member] Document Information [Line Items] Document Quarterly Report Document Information [Table] Interest and fees on loans Gain (Loss) on Securities [Table Text Block] dei_EntityInteractiveDataCurrent Entity Interactive Data Current ASSETS Measurement Frequency [Axis] Document Transition Report us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding Weighted average shares of common stock and common stock equivalents (in shares) Statement [Line Items] Change in contributions payable to LIHTC limited partner investment Amount of change in contributions commitment to limited partner investment. Fair Value Hierarchy and NAV [Axis] Common Stock, Shares, Issued (in shares) Common Stock, Shares, Outstanding (in shares) Common Stock, Shares Authorized (in shares) us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis Subtotal, amortized cost us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate Subtotal, fair value us-gaap_WeightedAverageNumberOfSharesOutstandingBasic Weighted average shares outstanding (in shares) Net income per share (in dollars per share) Net income per common share (in dollars per share) 90 Days or More Past Due and Accruing srt_FinancingReceivableBeforeAllowanceForCreditLossToTotalPercent Financing Receivable, before Allowance for Credit Loss, to Total, Percent Non-accrual without an Allowance Earnings Per Share, Basic, by Common Class, Including Two-Class Method [Table] Total Non-accrual Loans Financing Receivable, Excluding Accrued Interest, Nonaccrual Common stock, no par value; 50,000,000 shares authorized, 8,413,458 and 8,388,221 shares issued and outstanding at March 31, 2026 and December 31, 2025, respectively Net increase in demand deposits and savings accounts The net cash inflow (outflow) in the total of all savings account deposits, which may include passbook, statement savings accounts and money-market deposit accounts (MMDAs) and all demand deposits, including checking and negotiable order of withdrawal (NOW) accounts, classified as cash flows from financing activities. Debt Securities, Available-for-Sale [Table Text Block] Deposits us-gaap_PolicyTextBlockAbstract Accounting Policies us-gaap_DisclosureTextBlockAbstract Notes to Financial Statements us-gaap_TableTextBlock Notes Tables Document Fiscal Period Focus Federal funds sold Pledging Purpose [Axis] Document Fiscal Year Focus us-gaap_ComprehensiveIncomeNetOfTax Comprehensive income Pledging Purpose [Domain] Amendment Flag Common Stock [Member] Document Period End Date INTEREST INCOME Interest payable and other liabilities Amount of interest payable on debt, including, but not limited to, trade payable. Also the amount of liabilities classified as other Legal Entity [Axis] us-gaap_InterestAndDividendIncomeOperating Total interest income Fair Value Measurement and Measurement Inputs, Recurring and Nonrecurring [Text Block] Consumer Portfolio Segment [Member] Commercial Real Estate Portfolio Segment [Member] Proceeds from maturities, calls, and principal paydowns of available-for-sale securities Commercial Portfolio Segment [Member] Individually evaluated for impairment us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment dei_EntityFileNumber Entity File Number Change in unrealized gain (loss) on securities Collectively evaluated for impairment us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment Entity Tax Identification Number NON-CASH INVESTING ACTIVITIES: Collectively evaluated for impairment us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss Less than 12 months, unrealized loss us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss 12 months or more, unrealized loss Entity [Domain] Entity Central Index Key us-gaap_DebtSecurities Debt Securities dei_EntityRegistrantName Entity Registrant Name us-gaap_DepositsFairValueDisclosure Deposits dei_EntityCurrentReportingStatus Entity Current Reporting Status Special Mention [Member] us-gaap_DebtSecuritiesAvailableForSaleRealizedGainLoss Debt Securities, Available-for-Sale, Realized Gain (Loss) Substandard [Member] Entity Incorporation, State or Country Code Pass [Member] Current Fiscal Year End Date us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1 Tax (expense) benefit related to items of other comprehensive income Entity Filer Category dei_EntityShellCompany Entity Shell Company Entity Emerging Growth Company Entity Small Business Valuation Approach and Technique [Axis] Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] SBA Pool [Member] Securities classified as SBA Pools. INTEREST EXPENSE Valuation Approach and Technique [Domain] us-gaap_OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent Other comprehensive income (loss), before tax Residential Real Estate and Other Consumer Loans [Member] Loans classified as residential real estate and other consumer loans. Valuation, Market Approach [Member] Agriculture [Member] Loans classified as agriculture. us-gaap_InterestExpenseDeposits Deposits Other comprehensive income (loss): Entity Address, State or Province Statement of Stockholders' Equity [Abstract] Entity Address, City or Town Statement of Comprehensive Income [Abstract] ovly_UnderwritingStandardsHousingPercentage Underwriting Standards, Housing Percentage Represents the housing percentage as per the underwriting standards. Retained earnings us-gaap_InterestExpenseOperating Total interest expense ovly_UnderwritingStandardsLoanToValuePercentage Underwriting Standards, Loan to Value Percentage Represents the loan-to-value percentage as per the underwriting standards. Entity Address, Address Line One Statement of Cash Flows [Abstract] ovly_UnderwritingStandardsTotalDebtRatio Underwriting Standards, Total Debt Ratio Represents the total debt ratio as per the underwriting standards. dei_CityAreaCode City Area Code Due after one year through five years, amortized cost us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation Tax withholding payments on vested restricted shares surrendered Due after five years through ten years, amortized cost Financing Receivable Portfolio Segment [Axis] ovly_FinancingReceivableMinimumCashCollateralPercent Financing Receivable, Minimum Cash Collateral Percent The percentage of the loan amount for which cash collateral must be equal to or greater than in order for the loan to properly margined. dei_LocalPhoneNumber Local Phone Number Due in one year or less, amortized cost Entity Address, Postal Zip Code Other comprehensive gain Total other comprehensive income (loss) Shareholders’ equity Mortgage-backed securities and collateralized mortgage obligations, fair value Non-owner Occupied [member] Represents Non-owner Occupied. Title of 12(b) Security Equity Components [Axis] Owner Occupied [Member] Represents Owner Occupied. Security Exchange Name Due after five years through ten years, fair value Trading Symbol Due after ten years, fair value Due in one year or less, fair value Due after one year through five years, fair value Due after ten years, amortized cost Financing Receivable Portfolio Segment [Domain] Construction and Land [Member] Represents construction and land. Mortgage-backed securities and collateralized mortgage obligations, amortized cost Class of Stock [Axis] Equity Component [Domain] Class of Financing Receivable [Axis] Fair Value, Inputs, Level 2 [Member] Class of Financing Receivable [Domain] Fair Value, Inputs, Level 3 [Member] AOCI Attributable to Parent [Member] Fair Value, Inputs, Level 1 [Member] dei_EntityCommonStockSharesOutstanding Entity Common Stock, Shares Outstanding (in shares) Additional Paid-in Capital [Member] Retained Earnings [Member] Corporate Debt Securities [Member] Earnings Per Share [Text Block] Unrealized holding gain arising during the period Loans Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process Internal Credit Assessment [Axis] Bank premises and equipment, net Financial Asset, Aging [Axis] Farmland Loans [Member] Loan to finance the purchase of farm land. ovly_OperatingLeaseRightofuseAssetAmortizationReversal Amortization of operating lease right-of-use asset Amount of amortization or reversal over lease term of carrying amount of right-of-use asset from operating lease. Financing Receivable, Nonaccrual [Table Text Block] us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss Net interest income after provision for (reversal of) credit losses Deferred tax asset Financial Asset, Aging [Domain] ovly_DebtSecuritiesAvailableforsaleGainLossFromCalls Loss (gain) on sales and calls of available-for-sale securities Amount of realized gain (loss) from calls of investments in debt securities measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). ovly_InterestReceivableFairValueDisclosure Interest receivable Represents the fair value portion of interest receivable. Interest on deposits with banks Investments Classified by Contractual Maturity Date [Table Text Block] Interest on federal funds sold Provision for (reversal of) credit losses Provision for (reversal of) credit losses Internal Credit Assessment [Domain] ovly_InterestPayableFairValueDisclosure Interest payable Represents the fair value portion of interest payable. Financial Asset, 30 to 59 Days Past Due [Member] Stock based compensation Individually evaluated for impairment Fair Value Option, Disclosures [Table] Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest Allowance for credit losses Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest Beginning balance Ending balance Financial Asset, 60 to 89 Days Past Due [Member] Financial Asset, Equal to or Greater than 90 Days Past Due [Member] Fair Value Measurements, Recurring and Nonrecurring [Table Text Block] us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest Cash and due from banks us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax Less: reclassification for net losses (gains) included in net income us-gaap_Assets Assets Change in Allowance for Loan Losses [Table Text Block] Changes in the allowance off balance sheet commitments. us-gaap_CashAndCashEquivalentsAtCarryingValue Cash and cash equivalents Financing Receivable, Nonaccrual [Table] Financing Receivable, Year Five ovly_NumberOfDebtSecuritiesAvailableforsaleSold Number of Debt Securities, Available-for-sale, Sold The number of available for sale debt securities sold during the period. Financing Receivable, Prior Financing Receivable, Year Three Financing Receivable, Year Four Financing Receivable, Year One Financing Receivable, Year Two Fair Value, by Balance Sheet Grouping [Table Text Block] SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION: us-gaap_FinancingReceivableExcludingAccruedInterestModifiedPeriod Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount Interest on securities Net income per diluted share (in dollars per share) Net income per diluted common share (in dollars per share) Financing Receivable, Revolving us-gaap_RestrictedInvestmentsAtFairValue Restricted equity securities ovly_NumberOfCollateralDependentLoans Number of Collateral Dependent Loans Represents the number of collateral dependent loans. Measurement Input, Combination of Appraisals, Internally Determined Adjustments to Loan Value, and Customized Discounts [Member] Represents Measurement input using combination of appraisals, internally determined adjustments to loan value, and customized discounts. us-gaap_PaymentsToAcquireLimitedPartnershipInterests Investment in LIHTC Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] ovly_IndividualEvaluatedLoansMeasurementInput Individual Evaluated Loans, Measurement Input Value of input used to measure individual evaluated loans. Collateral Held [Domain] Non-accrual loans with an Allowance Amortized cost excluding accrued interest, of financing receivable on nonaccrual status with allowance for credit loss. Excludes net investment in lease. Collateral Held [Axis] ovly_StockSurrenderedForTaxWithholdingShares Restricted stock surrendered for tax withholding (in shares) The number of shares surrendered for tax withholding. Interest Cash surrender value of life insurance us-gaap_PaymentsToAcquireLifeInsurancePolicies Purchase of BOLI policies Accumulated other comprehensive loss, net of tax Common Stock, No Par Value (in dollars per share) Gross write offs, year prior Gross write offs, revolving Gross write offs, year four Gross write offs, year five Gross write offs, year two Gross write offs, year three Gross write offs, year one Basis of Accounting [Text Block] us-gaap_FinancingReceivableDeferredIncome Deferred loan fees and costs, net us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest Net income before provision for income taxes Data processing fees us-gaap_PaymentsToAcquireMarketableSecurities Purchases of equity securities Additional paid-in capital us-gaap_StockholdersEquity Total shareholders’ equity Balances Balances us-gaap_FinancingReceivableAccruedInterestAfterAllowanceForCreditLoss Financing Receivable, Accrued Interest, after Allowance for Credit Loss Restricted stock issued Amortization of investment securities, net us-gaap_PaymentsOfDividendsCommonStock Shareholder cash dividends paid us-gaap_PaymentsToAcquirePropertyPlantAndEquipment Purchases of premises and equipment Collateral Pledged [Member] Nature of Operation, Product Information, Concentration of Risk [Table] us-gaap_NoninterestExpense Total non-interest expense NON-INTEREST EXPENSE us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardForfeitures Restricted stock forfeited Financial Asset, Not Past Due [Member] us-gaap_DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLoss Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss ecd_Rule10b51ArrTrmntdFlag Rule 10b5-1 Arrangement Terminated [Flag] Other income ovly_NumberOfFormsOfOutstandingCommonStock Number Of Forms Of Outstanding Common Stock Represents the number of forms of outstanding stock awards available with the entity. ecd_Rule10b51ArrAdoptedFlag Rule 10b5-1 Arrangement Adopted [Flag] us-gaap_OffBalanceSheetCreditLossLiability Balance, beginning of year Balance, end of year