Document And Entity Information
Marketable Securities, Policy [Policy Text Block]
Note To Financial Statement Details Textual
Income tax expense
Total tax provision from continuing operations*
Significant Accounting Policies
Note 2 - Securities
Note 3 - Loans and Allowance for Credit Losses
Note 4 - Premises and Equipment
Note 5 - Goodwill and Acquired Intangible Assets
Note 6 - Deposits
Note 7 - Short-term Borrowings
Investment in Debt and Equity Securities and Other Trading Assets [Text Block]
Note 8 - Federal Home Loan Bank Advances
Note 9 - Employee Benefit Plans
us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
Investment in subsidiary
Note 10 - Income Taxes
Note 11 - Related Party Transactions
Note 12 - Regulatory Matters
Note 14 - Fair Value
Note 15 - Affordable Tax Credit Partnership
Note 16 - Parent Company Financial Statements
Note 17 - Earnings Per Share
Note 18 - Accumulated Other Comprehensive Income (Loss)
Note 19 - Revenue Recognition
Note 2 - Securities - Amortized Cost and Fair Value of Securities Available-for-sale and Securities Held-to-maturity (Details)
Note 2 - Securities - Proceeds From Sales and Calls of Available-for-sale Securities (Details)
Note 2 - Securities - Amortized Cost and Fair Values of Debt Securities by Contractual Maturity (Details)
Note 2 - Securities - Securities With Unrealized and Unrecognized Losses (Details)
Note 3 - Loans and Allowance for Credit Losses - Major Classifications (Details)
Note 3 - Loans and Allowance for Credit Losses - Allowance for Loan Losses by Portfolio Segment (Details)
Note 3 - Loans and Allowance for Credit Losses - Non-accrual Loans (Details)
Note 3 - Loans and Allowance for Credit Losses - Loans Past Due (Details)
Note 3 - Loans and Allowance for Credit Losses - Recorded Investment by Risk Category (Details)
Note 3 - Loans and Allowance for Credit Losses - Collateral Dependent Loans (Details)
Note 4 - Premises and Equipment - Major Classifications of Premises and Equipment (Details)
Note 4 - Premises and Equipment - Maturities of Lease Liabilities (Details)
Note 5 - Goodwill and Acquired Intangible Assets - Goodwill and Intangible Assets (Details)
Salaries and employee benefits
Note 6 - Deposits - Interest-bearing Deposits (Details)
Note 6 - Deposits - Maturities of Time Deposits (Details)
Note 7 - Short-term Borrowings - Summary of Short-term Borrowings (Details)
Note 7 - Short-term Borrowings - Schedule of Repurchase Agreements (Details)
Note 8 - Federal Home Loan Bank Advances - Summary of Federal Home Loan Bank (FHLB) Advances (Details)
Note 8 - Federal Home Loan Bank Advances - Summary of the Scheduled Principal Payments (Details)
Note 9 - Employee Benefit Plans - Summary of the Restricted Stock Awards (Details)
Land Improvements [Member]
Note 10 - Income Taxes - Provision for Income Taxes (Details)
Land [Member]
Note 10 - Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details)
Note 10 - Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details) (Parentheticals)
cbkm_AvailableforsaleQualitativeDisclosureNumberOfPositions
Available-for-sale, Qualitative Disclosure, Number of Positions
Number of investment positions in available-for-sale investments.
Note 10 - Income Taxes - Net Deferred Income Tax Asset (Details)
Note 11 - Related Party Transactions - Loans to Related Parties (Details)
Note 12 - Regulatory Matters - Schedule of Compliance With Regulatory Capital Requirements Under Banking Regulations (Details)
U.S. Government-sponsored Mortgage-backed and Related Securities [Member]
Debt securities collateralized by real estate mortgage loans (mortgages), issued by US Government Sponsored Enterprises.
Note 14 - Fair Value - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details)
Securities Sold under Agreements to Repurchase [Member]
Note 14 - Fair Value - Estimated Fair Values of Financial Instruments (Details)
Note 15 - Affordable Tax Credit Partnership - Investments in Affordable Housing Projects (Details)
Note 15 - Affordable Tax Credit Partnership - Investments in Affordable Housing Projects (Details) (Parentheticals)
Note 16 - Parent Company Financial Statements - Condensed Balance Sheets (Details)
Note 16 - Parent Company Financial Statements - Condensed Statements of Income and Comprehensive Income (Details)
Note 16 - Parent Company Financial Statements - Condensed Statements of Cash Flows (Details)
Note 17 - Earnings Per Share - Schedule of Earnings Per Share, Basic and Diluted (Details)
Note 18 - Accumulated Other Comprehensive Income (Loss) - Components of Other Comprehensive Income (Loss) (Details)
Note 19 - Revenue Recognition - Noninterest Income (Details)
Notes To Financial Statements
Notes To Financial Statements [Abstract]
Increase in cash surrender value of life insurance
Due after one year through five years, held-to-maturity, amortized cost
Preferred stock, no par value; 350,000 shares authorized
us-gaap_Liabilities
Total liabilities
Total liabilities
Banking Regulation, Regulatory Capital Requirement, Compliance [Table]
LIABILITIES:
Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table Text Block]
Due after five years through ten years, held-to-maturity, amortized cost
us-gaap_LiabilitiesAndStockholdersEquity
Total liabilities and shareholders’ equity
Total liabilities & shareholders’ equity
Pledged Status [Domain]
Pledged Status [Axis]
Net change in short-term borrowings
Net change in short-term borrowings
us-gaap_IncreaseDecreaseInOperatingCapital
Change in other assets and liabilities
Financial institutions tax
us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect
Increase in cash and cash equivalents
Change in cash and cash equivalents
Other expense
Shares associated with vested stock awards
Value, after forfeiture, of shares vested under share-based payment arrangement.
US Government-sponsored Enterprises Debt Securities [Member]
Capital Required to be Well Capitalized to Risk Weighted Assets
Capital to Risk Weighted Assets
us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations
Cash and cash equivalents, beginning of year
Cash and cash equivalents, end of year
Capital Required for Capital Adequacy to Risk Weighted Assets
Tier One Leverage Capital to Average Assets
Other comprehensive income, net of tax:
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets
Tier One Leverage Capital Required for Capital Adequacy to Average Assets
Tier One Leverage Capital Required to be Well Capitalized to Average Assets
Time
Total
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets
Tier 1 capital to risk weighted assets Bank
us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Line of Credit Facility, Maximum Borrowing Capacity
us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent
Derivative liabilities – interest rate swaps
us-gaap_DerivativeLiabilities
us-gaap_BankingRegulationCapitalConservationBufferCapitalConservedMinimum
Banking Regulation, Capital Conservation Buffer, Capital Conserved, Minimum
Financing Receivable, Allowance for Credit Loss [Table Text Block]
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
Restricted Stock, Outstanding, Beginning Balance (in shares)
Restricted Stock, Outstanding, Balance (in shares)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
Weighted-Average Grant Date Fair Value Per Share, Outstanding at Beginning Period (in dollars per share)
Weighted-Average Grant Date Fair Value Per Share, Outstanding (in dollars per share)
Restricted Stock Awards, Granted (in shares)
Financing Receivable, Past Due [Table Text Block]
Weighted-Average Grant Date Fair Value Per Share, Granted (in dollars per share)
Financing Receivable Credit Quality Indicators [Table Text Block]
us-gaap_LineOfCredit
Long-Term Line of Credit
Weighted-Average Grant Date Fair Value Per Share, Vested (in dollars per share)
us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period (in shares)
Restricted Stock Awards, Vested (in shares)
Thereafter
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive
Collateralized Mortgage Obligations [Member]
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue
Total undiscounted cash flows
us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent
Operating Lease, Weighted Average Discount Rate, Percent
us-gaap_LoansAndLeasesReceivableCommitmentsFixedRates
Loans and Leases Receivable, Commitments, Fixed Rates
2027
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths
2031
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive
Loans, including fees
us-gaap_OperatingLeaseExpense
Operating Lease, Expense
Gain (Loss) on Securities [Table Text Block]
Commitments to Extend Credit [Member]
Lessee, Operating Lease, Liability, to be Paid, Maturity [Table Text Block]
2029
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree
Measurement Frequency [Axis]
2028
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo
Liability Class [Axis]
2030
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour
us-gaap_LoansAndLeasesReceivableCommitmentsVariableRates
Loans and Leases Receivable, Commitments, Variable Rates
Fair Value Hierarchy and NAV [Axis]
Common stock, shares issued (in shares)
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]
Award Type [Domain]
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]
Common stock, shares authorized (in shares)
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]
Mortgage Banking Activity [Policy Text Block]
Fixed Rate Amortizing FHLB Advances [Member]
Information pertaining to fixed-rate amortizing FHLB advances.
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]
Fixed Rate FHLB Advances [Member]
Information pertaining to fixed-rate FHLB advances.
Schedule of Realized Gain (Loss) [Table Text Block]
Common shares, no par value; 8,500,000 shares authorized; 3,205,369 and 3,193,414 shares issued as of June 30, 2026 and June 30, 2025, respectively
Intangible Asset and Goodwill [Table Text Block]
Variable Rate FHLB Advances [Member]
Represents information related to variable rate for FHLB advances
us-gaap_PolicyTextBlockAbstract
Accounting Policies
us-gaap_DisclosureTextBlockAbstract
Notes to Financial Statements
us-gaap_TableTextBlock
Notes Tables
Comprehensive Income (Loss) Note [Text Block]
Comprehensive income
Total comprehensive income
Weighted average rate, June 30
Short-term borrowings
Short-term borrowings
Share-based Payment Arrangement, Tranche Two, Three and Tour[Member]
Represents tranche two, three an four of share based payment arrangement.
us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount
Less: present value discount
Total lease liabilities
Operating Lease, Liability
us-gaap_DepositsFairValueDisclosure
Demand and savings deposits
Condensed Financial Information of Parent Company Only Disclosure [Text Block]
us-gaap_DebtSecuritiesAvailableForSaleAndHeldToMaturityAllowanceForCreditLoss
Debt Securities, Available-for-Sale and Held-to-Maturity, Allowance for Credit Loss
us-gaap_OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList
Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration]
Statement of Stockholders' Equity [Abstract]
Statement of Comprehensive Income [Abstract]
Loss Contingency Nature [Axis]
us-gaap_EquitySecuritiesFvNiCurrentAndNoncurrent
Equity Securities, FV-NI
Statement of Cash Flows [Abstract]
us-gaap_OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]
Equity Components [Axis]
Core Deposits [Member]
Share-Based Payment Arrangement [Policy Text Block]
Equity Component [Domain]
AOCI Attributable to Parent [Member]
Retained Earnings [Member]
Loss Contingency, Nature [Domain]
Compensation and Employee Benefit Plans [Text Block]
Recorded investment
Total loans
Loans, Total
Financing Receivable, Nonaccrual [Table Text Block]
us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss
Held-to-maturity, amortized cost
us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss
Available-for-sale securities, amortized cost
Total securities available-for-sale, debt securities, amortized cost
Intangible Asset and Goodwill [Text Block]
Financing Receivable, Collateral Dependent Loans With An Allowance for Credit Loss
us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest
Less allowance for credit losses
Balance
Balance
Share-Based Payment Arrangement, Restricted Stock Unit, Activity [Table Text Block]
us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear
Loans, Year Five
us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear
Loans, Prior
Malpractice Loss Contingency, Policy [Policy Text Block]
us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear
Loans, Year Three
us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear
Loans, Year Four
us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear
Loans, Year One
us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear
Loans, Year Two
Cash paid during the period:
us-gaap_StatutoryAccountingPracticesStatutoryAmountAvailableForDividendPaymentsWithoutRegulatoryApproval
Statutory Accounting Practices, Statutory Amount Available for Dividend Payments without Regulatory Approval
Current income taxes
us-gaap_FinancingReceivableExcludingAccruedInterestRevolving
Loans, Revolving
us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingConvertedToTermLoan
Loans, Revolving Converted to Term
us-gaap_ShorttermDebtFairValue
Short-term borrowings
us-gaap_LoansHeldForSaleFairValueDisclosure
Loans held for sale
Redemption of equity securities
Proceeds from Sale of Equity Securities, FV-NI
Swap [Member]
Income taxes
Tier One Risk Based Capital Required for Capital Adequacy
Tier One Risk Based Capital Required to be Well Capitalized
Other Commitments [Table]
Tier One Risk Based Capital
Common stock, par value (in dollars per share)
Tier One Leverage Capital Required for Capital Adequacy
Tier One Leverage Capital Required to be Well Capitalized
Tier One Leverage Capital
2029
us-gaap_TimeDepositMaturitiesYearThree
2028
us-gaap_TimeDepositMaturitiesYearTwo
2030
us-gaap_TimeDepositMaturitiesYearFour
Federal Deposit Insurance Corporation assessments
Amount of expense (income) for Federal Deposit Insurance Corporation (FDIC) insurance.
2027
us-gaap_TimeDepositMaturitiesYearOne
Thereafter
us-gaap_TimeDepositMaturitiesAfterYearFive
2031
us-gaap_TimeDepositMaturitiesYearFive
Telephone and communications
Data processing expenses
Debt Disclosure [Text Block]
Segment Reporting, Policy [Policy Text Block]
Use of Estimates, Policy [Policy Text Block]
Capital Required for Capital Adequacy
Capital
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]
Issuance of stock-based incentive plan shares, net of forfeitures
Shares issued associated with dividend reinvestment plan and stock purchase plan
us-gaap_NoninterestExpense
Total noninterest expenses
Noninterest expenses:
Financial Asset, Not Past Due [Member]
Capital Required to be Well Capitalized
us-gaap_DefinedBenefitPlanOtherCosts
Defined Benefit Plan, Other Cost (Credit)
us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation
Shares Issued, Shares, Share-Based Payment Arrangement, after Forfeiture (in shares)
Restricted Stock Units (RSUs) [Member]
Shares issued associated with dividend reinvestment plan and stock purchase plan, shares (in shares)
Transfers and Servicing of Financial Assets, Policy [Policy Text Block]
Fair Value Measurement Inputs and Valuation Techniques [Table]
Related and Nonrelated Parties [Axis]
cbkm_EffectiveIncomeTaxRateReconciliationAffordableHousingTaxCredit
Affordable housing tax credit
The amount of income tax reconciliation related to the affordable housing investments.
Other Pledged Collateral [Member]
Represents the other assets pledged as collateral.
Schedule of Collateral Dependent Loans by Portfolio Segment and Collateral Type [Table Text Block]
Tabular disclosure of collateral dependent loans by portfolio segment and collateral type.
Schedule of Long-Term Debt Instruments [Table]
Cash flows from operating activities:
Cash flows from investing activities:
us-gaap_NetCashProvidedByUsedInOperatingActivities
Net cash flows from operating activities
Net cash flows from operating activities
Cash flows from financing activities:
us-gaap_NetCashProvidedByUsedInInvestingActivities
Net cash flows used in investing activities
us-gaap_NetCashProvidedByUsedInFinancingActivities
Net cash flows from financing activities
Net cash flows from financing activities
Net affordable housing tax credit investment
Amount of investment in qualified affordable housing projects, net of amortization.
Net increase in deposit accounts
Accounting Policies [Abstract]
Schedule of Investments in Affordable Housing Projects [Table Text Block]
Tabular disclosure of investments in affordable housing projects.
Farmland [Member]
Represents farmland.
Commercial & Industrial [Member]
Represents Commercial & Industrial.
Mortgage-Backed Security, Issued by US Government-Sponsored Enterprise [Member]
Land Development [Member]
Represents land development.
US Treasury Securities [Member]
US States and Political Subdivisions Debt Securities [Member]
us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss
Net loans
us-gaap_PaymentsForProceedsFromLoansAndLeases
Net increase in loans
Commercial, Commercial Real Estate, Farmland and Land Development Segment [Member]
Represents Commercial, Commercial Real Estate, Farmland and Land Development Segment.
Securities, available-for-sale
us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest
Available-for-sale securities, fair value
Total securities available-for-sale, debt securities, fair value
us-gaap_DeferredIncomeTaxLiabilities
Gross deferred tax liabilities
Securities, held-to-maturity (fair value in 2026 of $4,229 and 2025 of $5,026)
Debt Securities, Held-to-Maturity, Excluding Accrued Interest, after Allowance for Credit Loss
us-gaap_DeferredIncomeTaxExpenseBenefit
Deferred income tax benefit
Net income
Net income
Net income
us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic
Net income available to common shareholders
Financial Asset, Past Due [Member]
Mortgage banking activity
Mortgage banking activity
Provision for credit losses on unfunded commitments
Amount of provision for unfunded commitments expensed.
us-gaap_ForeclosedAssets
Repossessed Assets
us-gaap_InterestIncomeExpenseNet
Net interest income
us-gaap_DeferredTaxAssetsGross
Gross deferred tax asset
Issuance of stock-based incentive plan shares
us-gaap_DeferredTaxAssetsDeferredIncome
Deferred income
Accounting Standards Update and Change in Accounting Principle [Table]
us-gaap_DeferredTaxAssetsLiabilitiesNet
Net deferred asset
Other
us-gaap_DeferredTaxAssetsOther
Occupancy and equipment
us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits
Deferred compensation
us-gaap_OtherNoninterestExpense
Other
Bank owned life insurance income
Noninterest income (out-of-scope of Topic 606)
us-gaap_NoninterestIncome
Total noninterest income
Noninterest income:
Measurement Basis [Axis]
us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsProvisionForLoanLosses
Allowance for credit losses
us-gaap_NoninterestIncomeOther
Other
us-gaap_OpenTaxYear
Open Tax Year
Vesting [Axis]
Vesting [Domain]
Provision for expected credit losses
us-gaap_FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal
Marketing and advertising
us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRecovery
Recoveries
us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets
Intangible assets
us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff
Charge-offs
Loans, Total, Write-offs
us-gaap_DeferredTaxLiabilitiesOther
Other
dei_DocumentType
Document Type
Document Information [Line Items]
us-gaap_DefinedContributionPlanCostRecognized
Defined Contribution Plan, Cost
Document Annual Report
us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1
Operating Lease, Weighted Average Remaining Lease Term (Year)
Document Information [Table]
us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment
Dilutive effect of restricted stock (in shares)
dei_EntityInteractiveDataCurrent
Entity Interactive Data Current
Document Transition Report
us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding
Total common shares and dilutive potential common shares (in shares)
dei_DocumentFinStmtErrorCorrectionFlag
Document Financial Statement Error Correction [Flag]
us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis
us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate
Available-for-sale Securities, Debt Maturities, Single Maturity Date
us-gaap_WeightedAverageNumberOfSharesOutstandingBasic
Weighted average common shares outstanding (in shares)
Derivative Instrument [Axis]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing
us-gaap_FinancingReceivableExcludingAccruedInterest90DaysOrMorePastDueStillAccruing
Nonaccrual, No Allowance
us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage
Nonaccrual
Financing Receivable, Excluding Accrued Interest, Nonaccrual
us-gaap_InterestBearingDepositLiabilities
Total
Title and Position [Domain]
us-gaap_Deposits
Total deposits
Deposit Liabilities Disclosures [Text Block]
Noninterest-bearing demand
dei_IcfrAuditorAttestationFlag
ICFR Auditor Attestation Flag
Document Fiscal Period Focus
Pledging Purpose [Axis]
Document Fiscal Year Focus
Pledging Purpose [Domain]
Savings
Amendment Flag
Common Stock [Member]
Securities losses, net
us-gaap_DebtSecuritiesAvailableForSaleRealizedGain
Gross realized gains
us-gaap_DebtSecuritiesRealizedGainLoss
Loss on sale of securities
dei_DocumentPeriodEndDate
Document Period End Date
Interest and dividend income:
Property, Plant, and Equipment [Text Block]
Long-Lived Asset, Class [Domain]
Cash dividends from Bank subsidiary
Legal Entity [Axis]
us-gaap_InterestAndDividendIncomeOperating
Total interest and dividend income
dei_EntityFileNumber
Entity File Number
Entity Tax Identification Number
Non-cash items:
us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss
us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss
Entity [Domain]
Entity Central Index Key
dei_EntityRegistrantName
Entity Registrant Name
dei_EntityWellKnownSeasonedIssuer
Entity Well-known Seasoned Issuer
dei_EntityCurrentReportingStatus
Entity Current Reporting Status
us-gaap_DebtSecuritiesAvailableForSaleRealizedLoss
Gross realized losses
dei_EntityVoluntaryFilers
Entity Voluntary Filers
Entity Incorporation, State or Country Code
Current Fiscal Year End Date
dei_EntityPublicFloat
Entity Public Float
Entity Filer Category
dei_EntityShellCompany
Entity Shell Company
Entity Emerging Growth Company
Software, In-Development, Internally Developed, and Purchased [Member]
us-gaap_DerivativeNotionalAmount
Derivative, Notional Amount
Entity Small Business
Derivative assets - interest rate swaps
us-gaap_DerivativeAssets
us-gaap_Cash
Cash
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]
Equity securities
dei_EntityAddressStateOrProvince
Entity Address, State or Province
us-gaap_PaymentsForOriginationAndPurchasesOfLoansHeldForSale
Origination of loans held for sale
dei_EntityAddressCityOrTown
Entity Address, City or Town
Marketable Securities [Table]
dei_EntityAddressAddressLine1
Entity Address, Address Line One
dei_CityAreaCode
City Area Code
Increase (Decrease) in Other Operating Assets and Liabilities, Net
Net change in other assets and other liabilities
Available-for-sale Securities, Debt Maturities, Year Two Through Five, Amortized Cost Basis
Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Amortized Cost Basis
dei_LocalPhoneNumber
Local Phone Number
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Amortized Cost Basis
dei_EntityAddressPostalZipCode
Entity Address, Postal Zip Code
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value
Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Fair Value
Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value
Derivatives, Policy [Policy Text Block]
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value
Available-for-sale Securities, Debt Maturities, Year Two Through Five, Fair Value
Available-for-sale Securities, Debt Maturities, after Ten Years, Amortized Cost Basis
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis
Available for sale debt securities
us-gaap_AvailableForSaleSecuritiesDebtSecurities
Title of 12(g) Security
dei_EntityCommonStockSharesOutstanding
Entity Common Stock, Shares Outstanding (in shares)
us-gaap_DerivativeAssetFairValueGrossLiability
Derivative Asset, Subject to Master Netting Arrangement, Liability Offset
us-gaap_DerivativeLiabilityFairValueGrossAsset
Derivative Liability, Subject to Master Netting Arrangement, Asset Offset
Earnings Per Share [Text Block]
Preferred stock, par value (in dollars per share)
us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax
Unrealized holding losses on available-for-sale securities arising during the period, tax
Unrealized gains arising during the period
Gross loans
us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLossFeeAndLoanInProcess
Internal Credit Assessment [Axis]
Unrealized holding losses on available-for-sale securities arising during the period, net
Other Debt Obligations [Member]
Debt Securities, Held-to-Maturity, Fair Value
Held-to-maturity, fair value
Total, held-to-maturity, fair value
Issuance of treasury stock for stock awards
The fair value of treasury stock issued for stock awards.
Investments Classified by Contractual Maturity Date [Table Text Block]
Off-Balance-Sheet Credit Exposure, Policy [Policy Text Block]
Internal Credit Assessment [Domain]
Due after five years through ten years, held-to-maturity, fair value
Due after one year through five years, held-to-maturity, fair value
us-gaap_OtherLiabilities
Other liabilities
us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value
Parent Company [Member]
Amounts reclassified from accumulated other comprehensive income, tax
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax
us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax
Reclassification adjustment for net losses included in income
Regulatory Capital Requirements under Banking Regulations [Text Block]
us-gaap_Assets
Total assets
Total assets
us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax
Amounts reclassified from accumulated other comprehensive income, net
dei_AuditorFirmId
Auditor Firm ID
Condensed Financial Statements [Table]
dei_AuditorName
Auditor Name
dei_AuditorLocation
Auditor Location
cbkm_PercentOfAvailableForSaleDebtSecuritiesPortfolio
Percent of Available for Sale Debt Securities Portfolio
The percent of available for sale debt securities portfolio.
Non-rated [Member]
Related to non-rated securities.
Rated [Member]
Related to rated securities.
us-gaap_DefinedContributionPlanEmployersMatchingContributionAnnualVestingPercentage
Defined Contribution Plan, Employers Matching Contribution, Annual Vesting Percentage
us-gaap_NotesReceivableGross
Principal balance, July 1
Principal balance, June 30
us-gaap_EarningsPerShareDiluted
Dilutive income per share (in dollars per share)
us-gaap_OtherRealEstate
Other Real Estate
External Credit Rating, Standard & Poor's [Domain]
Accounts and Financing Receivables [Table]
Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]
Consolidation, Policy [Policy Text Block]
us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearWriteoff
Loans, Prior, Write-offs
us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingWriteoff
Loans, Loans, Revolving, Write-offs
us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff
Loans, Year Four, Write-offs
us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff
Loans, Year Five, Write-offs
us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff
Loans, Year Two, Write-offs
us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff
Loans, Year Three, Write-offs
us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearWriteoff
Loans, Year One, Write-offs
us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingConvertedToTermLoanWriteoff
Loans, Revolving Converted to Term, Write-offs
Award Timing MNPI Disclosure [Text Block]
us-gaap_PaymentsOfDividendsCommonStock
Dividends paid
ecd_AwardTmgMnpiCnsdrdFlag
Award Timing MNPI Considered [Flag]
us-gaap_PaymentsOfDividends
Dividends paid
cbkm_PolicyTable
Award Timing Disclosures [Line Items]
us-gaap_RepaymentsOfFederalHomeLoanBankBorrowings
Repayments of Federal Home Loan Bank advances
ecd_Rule10b51ArrTrmntdFlag
Rule 10b5-1 Arrangement Terminated [Flag]
ecd_Rule10b51ArrAdoptedFlag
Rule 10b5-1 Arrangement Adopted [Flag]
Marketable Securities [Table Text Block]
Statistical Measurement [Axis]
ecd_NonRule10b51ArrTrmntdFlag
Non-Rule 10b5-1 Arrangement Terminated [Flag]
Financial Service, Other [Member]
ecd_NonRule10b51ArrAdoptedFlag
Non-Rule 10b5-1 Arrangement Adopted [Flag]
Debit Card [Member]
Trading Arrangements, by Individual [Table]
Deposit Account [Member]
Material Terms of Trading Arrangement [Text Block]
Insider Trading Policies and Procedures Adopted [Flag]
Insider Trading Policies and Procedures Adopted [Flag]
Financial Instrument [Axis]
us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss
us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss
Held-to-maturity, gross unrecognized losses
us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain
Held-to-maturity, gross unrecognized gains
Comprehensive Income, Policy [Policy Text Block]
us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Available-for-sale securities, gross unrealized losses
Minimum [Member]
us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax
Available-for-sale securities, gross unrealized gains
Statistical Measurement [Domain]
Insider Trading Policies and Procedures [Line Items]
Maximum [Member]
Federal Home Loan Bank, Advances [Table]
us-gaap_ConcentrationRiskCreditRiskFinancialInstrumentMaximumExposure
Concentration Risk, Credit Risk, Financial Instrument, Maximum Exposure
us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation
Defined Benefit Plan, Accumulated Benefit Obligation
Commercial Mortgage-Backed Securities [Member]
us-gaap_DebtSecuritiesAvailableForSaleRestricted
Debt Securities, Available-for-Sale, Restricted
Condensed Cash Flow Statement [Table Text Block]
us-gaap_EffectiveIncomeTaxRateContinuingOperations
Total, percent
Condensed Balance Sheet [Table Text Block]
Condensed Income Statement [Table Text Block]
U.S. Federal statutory tax rate, percent
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent
us-gaap_DefinedBenefitPlanContributionsByEmployer
Defined Benefit Plan, Plan Assets, Contributions by Employer
Collateralized Debt Obligations [Member]
us-gaap_DividendsCommonStockCash
Cash dividends declared
Income Tax Jurisdiction [Domain]
us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate
Financial Instruments [Domain]
Common Stock, Dividends, Per Share, Declared (in dollars per share)
Asset Pledged as Collateral [Member]
State and local income taxes, net of federal income tax effect, percent
Other, nontaxable or nondeductible items, percent
Investments in Affordable Housing Tax Credits Projects [Text Block]
The entire disclosure for investments in affordable housing tax credit projects.
Investments in Affordable Housing Tax Credits Projects [Policy Text Block]
Disclosure of accounting policy for investments in affordable housing tax credits projects.
Directors and Senior Management [Member]
Represents directors and senior management.
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value
us-gaap_EffectiveIncomeTaxRateReconciliationTaxExemptIncome
Tax-exempt income, net of TEFRA, percent
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value
us-gaap_EffectiveIncomeTaxRateReconciliationTaxCreditsOther
Other, tax credits, percent
Award Type [Axis]
Adjustments to reconcile net income to net cash flows from operating activities:
cbkm_HeldToMaturityQualitativeDisclosureNumberOfPositions
Held-to-maturity, Qualitative Disclosure, Number of Positions
Number of investment positions in held-to-maturity investments.
Defined Benefit Plan [Table]
Executive Officers, Directors and Their Affiliates [Member]
Represents information about executive officers, directors and their affiliates.
us-gaap_AllocatedShareBasedCompensationExpense
Share-Based Payment Arrangement, Expense
Title and Position [Axis]
Credit Rating, Standard & Poor's [Axis]
us-gaap_FiniteLivedIntangibleAssetUsefulLife
Finite-Lived Intangible Asset, Useful Life (Year)
Preferred stock, shares authorized (in shares)
Portion at Fair Value Measurement [Member]
Reported Value Measurement [Member]
Partnership investment
Proceeds from dividend reinvestment and stock purchase plan
Proceeds from dividend reinvestment and stock purchase plan
us-gaap_DeferredTaxLiabilitiesPrepaidExpenses
Prepaid expenses
us-gaap_CashAndCashEquivalentsFairValueDisclosure
Cash and cash equivalents
Estimate of Fair Value Measurement [Member]
New Accounting Pronouncements, Policy [Policy Text Block]
Concentration Risk, Credit Risk, Policy [Policy Text Block]
Antidilutive Securities, Name [Domain]
Share-Based Payment Arrangement, Tranche One [Member]
Statement [Table]
Federal bank and other restricted stocks
Interest income from investment in federal bank and other restricted stocks.
Accrued interest payable and other liabilities
us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss
us-gaap_LoansReceivableFairValueDisclosure
Loans, net
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value
Equity securities
Equity securities, at fair value
us-gaap_AccruedLiabilitiesFairValueDisclosure
Accrued interest payable
Product and Service, Out of Scope of ASC 606 [Member]
Represents the product and service that out of scope of ASC 606.
Average balance during the year
us-gaap_EquitySecuritiesFvNiRealizedGainLoss
Equity Securities, FV-NI, Realized Gain (Loss)
Long-Term Debt, Type [Axis]
us-gaap_FederalHomeLoanBankBorrowingsFairValueDisclosure
Federal Home Loan Bank advances
us-gaap_EquitySecuritiesFvNiCost
Equity Securities, FV-NI, Cost
Condensed Income Statement [Table]
Maximum month-end balance
Net change in market value of equity securities
Net change in market value of equity securities
Product and Service [Domain]
Product and Service [Axis]
us-gaap_PropertyPlantAndEquipmentUsefulLife
Property, Plant and Equipment, Useful Life (Year)
Consolidated Entities [Axis]
Consolidated Entities [Domain]
us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss
Net change in market value of equity securities
Equity Securities, FV-NI, Unrealized Gain (Loss)
us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledged1
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged
Residential Mortgage-Backed Securities [Member]
ASSETS:
us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities
Proceeds from sales
Statement [Line Items]
Proceeds from Federal Home Loan Bank advances
Savings and money market
Amount of interest bearing deposits with no stated maturity and deposits in accounts that offer many of the same services as checking accounts although transactions may be somewhat more limited, share some of the characteristics of a money market fund and are insured by the Federal government, also known as money market accounts.
Other
Amount of time deposit liabilities, including certificates of deposit, classified as other.
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo
Finite-Lived Intangible Asset, Expected Amortization, Year One
Proportional amortization expense included in provision for income taxes
Less: amortization
Fair Value of Financial Instruments, Policy [Policy Text Block]
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree
Intangible Asset, Finite-Lived, Estimated Amortization Expense, Year Three
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths
Finite-Lived Intangible Asset, Expected Amortization, Year Two
Affordable housing tax credit investment
Unfunded commitments
Tax credits and other tax benefits recognized
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour
Intangible Asset, Finite-Lived, Estimated Amortization Expense, Year Four
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive
Intangible Asset, Finite-Lived, Estimated Amortization Expense, Year Five
us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresAmountOfAvailableUnusedFunds
Federal Home Loan Bank, Advances, General Debt Obligations, Amount of Available, Unused Funds
Federal Home Loan Bank Advances, Disclosure [Text Block]
Weighted average rate
Related Party [Member]
Federal Home Loan Bank advances
Maturities, calls and principal pay downs
us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities
Principal pay downs
Stated Interest rate range
Schedule of Related Party Transactions [Table Text Block]
Loans held for sale
Federal Home Loan Bank, Advance, Branch of FHLBank [Table Text Block]
2027
us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryDueWithinOneYearOfBalanceSheetDate
2030
us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromThreeToFourYearsOfBalanceSheetDate
Income Tax Jurisdiction, Domestic Federal [Member]
Disposal of premises and equipment
Proceeds from sale of other real estate and repossessed assets owned
Financial Standby Letter of Credit [Member]
Net current period other comprehensive income, before tax
Net current period other comprehensive income, before tax
Intangible Asset, Finite-Lived, Class [Axis]
Intangible Asset, Finite-Lived, Class [Domain]
Proceeds from loans held for sale
Financing Receivable Portfolio Segment [Axis]
Other comprehensive income
Net current period other comprehensive income, net
Other comprehensive income
Long-Term Debt, Type [Domain]
Financing Receivable Portfolio Segment [Domain]
Fair Value, Inputs, Level 2 [Member]
Fair Value, Inputs, Level 3 [Member]
Fair Value, Inputs, Level 1 [Member]
Federal funds sold and interest-bearing deposits
Interest income on federal funds sold. Federal funds sold represent the excess federal funds held by one commercial bank which it lends to another commercial bank, usually at an agreed-upon (federal funds) rate of interest. Such loans are made for legal reserve requirement purposes of the borrowing bank and generally are of short-duration (overnight). It also includes the interest income from aggregate of all domestic and foreign interest-bearing deposit.
Professional and director fees
A fee charged for services from professionals such as doctors, lawyers, accountants. And also includes director fees.
Debit card processing expenses
Expenses incurred for debit card processing services.
Loan and collection expenses
The aggregate amount of expenditures for loan and collection.
Real Estate [Member]
Financial Instrument Performance Status [Domain]
Premises and equipment, net
Premises and equipment, net
Financial Asset, Aging [Axis]
Premises and equipment, gross
Financial Instrument Performance Status [Axis]
Financial Asset, Aging [Domain]
Property, Plant, and Equipment [Policy Text Block]
us-gaap_ProvisionForLoanLossesExpensed
Provision for credit losses on loans
Provision for credit losses
Nature of Operations [Policy Text Block]
Disclosure of accounting policy for nature of operations.
Interest Bearing Deposits in Other Financial Institutions [Policy Text Block]
Disclosure of accounting policy for Interest-bearing deposits in other financial institutions for relatively short periods of time including, for example, certificates of deposits, which are presented separately from cash on the balance sheet.
Financial Asset, 30 to 59 Days Past Due [Member]
Cash Surrender Value of Life Insurance [Policy Text Block]
Disclosure of accounting policy for cash which could be received based on the terms of the insurance contract upon surrendering life policies owned by the entity.
Furniture and Fixtures [Member]
Federal Home Loan Bank FHLB Stock [Policy Text Block]
Disclosure of accounting policy for borrowings and other factors, advances by federal home loan bank by branch.
Dividend Restrictions [Policy Text Block]
Disclosure of accounting policy for statutory restrictions on the payment of dividends as prescribed by the Office of the Comptroller of Currency or other regulatory authorities.
Long-term Assets [Policy Text Block]
Disclosure of accounting policy for long term assets.
Equity [Abstract]
Financial Asset, 60 to 89 Days Past Due [Member]
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Fair Value Disclosures [Text Block]
Fair Value, by Balance Sheet Grouping [Table Text Block]
us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions
Issuance of treasury stock for stock awards
us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments
Securities amortization and accretion, net
Equity Securities [Policy Text Block]
Disclosure of accounting policy for investment in equity security.
Collateral Held [Domain]
Collateral Held [Axis]
us-gaap_InvestmentProportionalAmortizationMethodElectedStatementOfFinancialPositionExtensibleEnumeration
Investment, Proportional Amortization Method, Elected, Statement of Financial Position [Extensible Enumeration]
us-gaap_GainLossOnSaleOfPropertyPlantEquipment
Gain on disposal of fixed assets
us-gaap_PaymentsToAcquireLifeInsurancePolicies
Purchase of bank owned life insurance
us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment
Accumulated depreciation and amortization
Accumulated other comprehensive loss
Accumulated other comprehensive income (loss), net
Accumulated other comprehensive income (loss), net
us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
Core deposit intangible
us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest
Income before income taxes
Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Text Block]
Non-owner Occupied Loans [Member]
Represents the information pertaining to non-owner occupied loans.
Owner Occupied Loans [Member]
Represents the information pertaining to owner occupied loans.
us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year)
us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
Acquisition of premises and equipment
Collateral Pledged [Member]
Goodwill and Intangible Assets, Policy [Policy Text Block]
us-gaap_InvestmentProgramProportionalAmortizationMethodAppliedIncomeTaxCreditAndOtherTaxBenefitAmortizationStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration
Investment Program, Proportional Amortization Method, Applied, Amortization Expense, Statement of Income or Comprehensive Income [Extensible Enumeration]
Building And Leasehold Improvements [Member]
Represents the information pertaining to building and leasehold improvements.
Average interest rate during the year
The average effective interest rate during the reporting period.
cbkm_PrepaymentPenaltyForAdvancesReceivedPercentageOfLostCashFlow
Prepayment Penalty for Advances Received, Percentage of Lost Cash Flow
The percentage of lost cash flow based upon the difference between the contract rate on the advance and the current rate on the new advance as prepayment penalty.
us-gaap_InvestmentProgramProportionalAmortizationMethodElectedIncomeTaxCreditAndOtherIncomeTaxBenefitBeforeAmortizationStatementOfCashFlowsExtensibleEnumeration
Investment Program, Proportional Amortization Method, Elected, Income Tax Credit and Other Income Tax Benefit, before Amortization, Statement of Cash Flows [Extensible Enumeration]
us-gaap_InvestmentProgramProportionalAmortizationMethodElectedIncomeTaxCreditAndOtherIncomeTaxBenefitBeforeAmortizationStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration
Investment Program, Proportional Amortization Method, Elected, Income Tax Credit and Other Income Tax Benefit, before Amortization, Statement of Income or Comprehensive Income [Extensible Enumeration]
Goodwill [Table]
us-gaap_InvestmentProgramProportionalAmortizationMethodAppliedIncomeTaxCreditAndOtherTaxBenefitAmortizationStatementOfCashFlowsExtensibleEnumeration
Investment Program, Proportional Amortization Method, Applied, Amortization Expense, Statement of Cash Flows [Extensible Enumeration]
Credit Loss, Financial Instrument [Policy Text Block]
Accumulated other comprehensive income (loss), tax
Accumulated other comprehensive income (loss), tax
us-gaap_AociTaxAttributableToParent
us-gaap_AociBeforeTaxAttributableToParent
Accumulated other comprehensive income (loss), before tax
Accumulated other comprehensive income (loss), before tax
Depreciation
Depreciation
us-gaap_TreasuryStockValue
Treasury stock, at cost (48,639 common shares at June 30, 2026 and 2025)
Residential Real Estate and Consumer Segments [Member]
Represents residential real estate and consumer segments.
FHLB advance amount
Total
us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt
Purchases
Proceeds from sales of available-for-sale securities
us-gaap_AssetsFairValueDisclosure
Assets, Fair Value Disclosure
Loans, Notes, Trade and Other Receivables Disclosure [Text Block]
us-gaap_GoodwillImpairmentLoss
Goodwill, Impairment Loss
First Mortgage Loans [Member]
Represents the information to first mortgage loans.
Financing Receivable, Held-for-Sale [Policy Text Block]
Financing Receivable, Held-for-Investment, Foreclosed Asset [Policy Text Block]
Accrued interest receivable and other assets
Schedule of Principal Payments [Table Text Block]
Tabular disclosure of federal home loan bank's principal payment schedule.
Income Statement [Abstract]
cbkm_DeferredTaxAssetsNonAccrualLoanInterestIncome
Non-accrual loan interest income
Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from deferred interest income on nonaccrual loans.
cbkm_DeferredTaxLiabilitiesLoanFees
Loan fees
Amount of deferred tax liability attributable to taxable temporary differences from deferred loan fees.
us-gaap_NumberOfReportableSegments
Number of Reportable Segments
Repurchase agreements
cbkm_DeferredTaxLiabilitiesFederalHomeLoanBankStockDividends
FHLB stock dividends
Amount of deferred tax liability attributable to taxable temporary differences from stock dividends received from the Federal Home Loan Bank.
cbkm_IncomeTaxReconciliationCashSurrenderValueIncome
Cash surrender value income
The portion of the difference between total income tax expense or benefit as reported in the Income Statement for the period and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to earnings or other increases in the value of the cash surrender value of bank owned life insurance policies that are exempt from income taxes under enacted tax laws.
Treasury stock, shares (in shares)
Treasury Stock, Common [Member]
Common Equity Tier One Risk Based Capital to Risk Weighted Assets
Common Equity Tier 1 capital divided by risk weighted assets as defined by regulations.
Common Equity Tier One Risk Based Capital
Common Equity Tier 1 Risk Based Capital as defined in the regulations.
Common Equity Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets
The minimum Common Equity Tier One Capital Ratio (Common Equity Tier one capital divided by risk-weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.
Common Equity Tier One Risk Based Capital Required for Capital Adequacy
The minimum amount of Common Equity Tier 1 Risk Based Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action.
Common Equity Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets
The Common Equity Tier 1 capital ratio (Common Equity Tier 1 capital divided by risk weighted assets) required to be categorized as "well capitalized" under the regulatory framework for prompt corrective action.
Common Equity Tier One Risk Based Capital Required to be Well Capitalized
The amount of Common Equity Tier 1 Risk Based Capital required to be categorized as well capitalized under the regulatory framework for prompt corrective action.
Amortization of intangibles
Amortization of intangible
Amortization of Intangible Assets
Commitments with Off-Balance Sheet Risk Disclosure [Text Block]
The entire disclosure of the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined) which are not recognized in the financial statements (off-balance sheet) because they fail to meet some other criterion for recognition.
cbkm_LoansAndLeasesReceivableCommitmentsFixedRatesPercentage
Loans and Leases Receivable Commitments Fixed Rates Percentage
The lowest stated interest rate within the commitments to fund advances to borrowers at fixed interest rates.
cbkm_AccruedInterestReceivableFairValueDisclosure
Accrued interest receivable
Fair value portion of accrued interest receivable.
us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued
Income before equity in undistributed net income of Bank subsidiary
Sum of operating profit and nonoperating income or expense before Income or Loss from equity method investments in undistributed net income of subsidiary.
us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense
us-gaap_LoansAndLeasesReceivableRelatedPartiesProceeds
Repayments
Equity in undistributed net income of subsidiary
Equity in undistributed net income of Bank subsidiary
The amount of undistributed earnings from subsidiaries.
Income Tax Disclosure [Text Block]
Restricted Stock [Member]
Nonaccrual, Interest Income
Income Tax, Policy [Policy Text Block]
U.S. Federal statutory tax rate
Related and Nonrelated Parties [Domain]
us-gaap_RelatedPartyDepositLiabilities
Related Party Deposit Liabilities
Related Party Transaction [Table]
Related Party Transactions Disclosure [Text Block]
State and local income taxes, net of federal income tax effect
Other, nontaxable or nondeductible items
us-gaap_IncomeTaxReconciliationTaxCreditsOther
Other, tax credits
Fair Value Hierarchy and NAV [Domain]
Demand and Savings Deposits [Member]
Represents the information pertaining to demand and savings deposits.
Transfer from loans to other repossessed assets
Measurement Frequency [Domain]
Time Deposits [Member]
Represents the information pertaining to time deposits.
Statement of Financial Position [Abstract]
us-gaap_IncomeTaxReconciliationTaxExemptIncome
Tax-exempt income, net of TEFRA
Deposit Liability [Table]
$250 and over
us-gaap_OtherAssets
Other assets
Fair Value, Nonrecurring [Member]
Fair Value, Recurring [Member]
Repurchase and Resale Agreements Policy [Policy Text Block]
us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount
Antidilutive Securities [Axis]
us-gaap_BankOwnedLifeInsurance
Bank Owned Life Insurance
Basic and diluted earnings per share (in dollars per share)
Basic income per share (in dollars per share)
Earnings Per Share, Diluted, by Common Class, Including Two-Class Method [Table]
Effective Income Tax Rate Reconciliation [Table]
Pension and Other Postretirement Plans, Policy [Policy Text Block]
us-gaap_TaxJurisdictionOfDomicileExtensibleEnumeration
Tax Jurisdiction of Domicile [Extensible Enumeration]
Earnings Per Share, Policy [Policy Text Block]
us-gaap_FiniteLivedCoreDepositsGross
Core deposit intangible
Core deposit intangible, net
us-gaap_FinancingReceivableUnamortizedLoanCommitmentOriginationFeeAndPremiumDiscount
Financing Receivable, Unamortized Loan Cost (Fee) and Purchase Premium (Discount)
Goodwill
Goodwill
us-gaap_PaymentsToAcquireFederalHomeLoanBankStock
Purchases of FHLB stock
Proceeds from redemption of FHLB stock
Federal bank and other restricted stocks, at cost
Building [Member]
Residential Portfolio Segment [Member]
Consumer Portfolio Segment [Member]
Commercial Real Estate Portfolio Segment [Member]
Commercial Portfolio Segment [Member]
us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax
Net unrealized gain
Disaggregation of Revenue [Table Text Block]
Disaggregation of Revenue [Table]
Doubtful [Member]
Performing Financial Instruments [Member]
Special Mention [Member]
Substandard [Member]
Interest bearing demand
Policy Loans Receivable, Policy [Policy Text Block]
Pass [Member]
us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1
Net current period other comprehensive income, tax
Net current period other comprehensive income, tax
us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesTax
Income tax effect
Nonperforming Financial Instruments [Member]
Interest expense:
Interest expense
us-gaap_InterestBearingDepositsInBanks
Federal funds sold and interest-bearing deposits in financial institutions
Deposits
Retained earnings
us-gaap_InterestExpenseOperating
Total interest expense
Revenue from Contract with Customer [Text Block]
Income before income taxes and equity in undistributed net income of subsidiary
Class of Stock [Axis]
us-gaap_InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesLongTerm
Federal Home Loan Bank advances
Class of Financing Receivable [Axis]
Class of Financing Receivable [Domain]
Short-term borrowings
us-gaap_InterestExpenseShortTermBorrowings
Interest Expense, Short-Term Borrowings
us-gaap_FairValueDisclosureOffbalanceSheetRisksFaceAmountLiability
Fair Value Disclosure, off-Balance-Sheet Risks, Face Amount, Liability
Deferred income tax (benefit) expense
us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss
Net interest income after provision for credit losses
Property, Plant, and Equipment [Table]
Securities, taxable
Securities, tax-exempt
Derivative Contract [Domain]
Long-Lived Asset, Class [Axis]
Cash on hand and noninterest-bearing deposits in financial institutions
us-gaap_CashCashEquivalentsAndFederalFundsSold
Total cash and cash equivalents
Cash and Cash Equivalents, Policy [Policy Text Block]
us-gaap_CashAndCashEquivalentsAtCarryingValue
Beginning cash and cash equivalents
Ending cash and cash equivalents
cbkm_QualitativeDisclosureNumberOfPositions
Available-for-sale, Qualitative Disclosure, Number of Positions
Number of securities in the Company's portfolio.
Time Deposit Maturities [Table Text Block]
Net unrealized securities loss
Loan Commitments, Policy [Policy Text Block]
cbkm_DebtSecuritiesHeldtomaturityContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
Held-to-Maturity, Continuous Unrealized Loss Positions, Less than 12 Months, Aggregate Loss
Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity), in continuous loss position for less than 12 months.
cbkm_DebtSecuritiesHeldtomaturityContinuousUnrealizedLossPositionsLessThan12MonthsFairValue
Held-to-Maturity, Continuous Unrealized Loss Positions, Less than 12 Months, Fair Value
Fair value of investment in debt security measured at amortized cost (held-to-maturity), in continuous unrealized loss position for less than 12 months.
cbkm_DebtSecuritiesHeldtomaturityContinuousUnrealizedLossPosition12MonthsOrLongerFairValue
Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or More, Fair Value
Fair value of investment in debt security measured at amortized cost (held-to-maturity), in continuous unrealized loss position for 12 months or longer.
cbkm_DebtSecuritiesHeldtomaturityContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLosses
Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or More, Aggregate Loss
Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity), in continuous loss position for 12 months or longer.
cbkm_DebtSecuritiesHeldtomaturityUnrealizedLossPositionAccumulatedLosses
Held-to-maturity, Continuous Unrealized Loss Position, Aggregate Loss
Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity), in unrealized loss position.
Fair Value by Liability Class [Domain]
cbkm_DebtSecuritiesHeldtomaturityUnrealizedLossPositionsFairValue
Held-to-maturity, Continuous Unrealized Loss Position, Fair Value
Fair value of investment in debt security measured at amortized cost (held-to-maturity), in unrealized loss position.
Interest
us-gaap_FinancingReceivableAccruedInterestAfterAllowanceForCreditLossStatementOfFinancialPositionExtensibleList
Financing Receivable, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]
Cash surrender value of life insurance
Cash Surrender Value of Life Insurance
cbkm_EffectiveIncomeTaxRateReconciliationTaxCreditAffordableHousingPercent
Affordable housing tax credit, percent
Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to affordable housing tax credits.
cbkm_EffectiveIncomeTaxRateReconciliationCashSurrenderValueIncomePercent
Cash surrender value income, percent
Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to cash surrender value income.
Deposit Liabilities, Type [Table Text Block]
us-gaap_StockholdersEquity
Total shareholders’ equity
Shareholders’ equity
Balance
Balance
us-gaap_FinancingReceivableAccruedInterestAfterAllowanceForCreditLoss
Financing Receivable, Accrued Interest, after Allowance for Credit Loss
Schedule of Short-Term Debt [Table Text Block]
us-gaap_OperatingLeaseRightOfUseAsset
Operating Lease, Right-of-Use Asset
Schedule of Repurchase Agreements [Table Text Block]
us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment
Depreciation
Property, Plant, and Equipment [Table Text Block]
Service charges on deposit accounts
Noninterest income (in scope of Topic 606)