Document And Entity Information Securities available for sale, due after ten years, fair value us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue Note To Financial Statement Details Textual Derivative expense Significant Accounting Policies us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis Securities available for sale, single maturity date, amortized cost Note 2 - Acquisitions and Divestitures Securities available for sale, due within one year, amortized cost us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost Note 3 - Debt Securities us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate Securities available for sale, single maturity date, fair value Note 4 - Loans Securities available for sale, due within one year, fair value us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue Note 5 - Credit Quality Securities available for sale, due after one year but within five years, fair value us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue Note 6 - Allowance for Loan Losses Securities available for sale, due after five years but within ten years, fair value us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue Note 7 - FDIC Indemnification Asset Collateralized Mortgage Backed Securities [Member] Note 8 - Premises, Equipment, and Leases Note 9 - Goodwill and Other Intangible Assets Note 10 - Deposits Note 11 - Borrowings Note 12 - Derivative Instruments and Hedging Activities Note 13 - Employee Benefit Plans Note 14 - Other Operating Income and Expense Note 15 - Income Taxes Note 16 - Accumulated Other Comprehensive Income Note 17 - Fair Value Note 18 - Earnings Per Share Note 19 - Related Party Transactions Note 20 - Litigation, Commitments, and Contingencies Note 21 - Regulatory Requirements and Restrictions Note 22 - Parent Company Financial Information Consumer Loan [Member] Note 23 - Quarterly Financial Data (Unaudited) US States and Political Subdivisions Debt Securities [Member] Note 2 - Acquisitions and Divestitures - Acquisition (Details) Note 2 - Acquisitions and Divestitures - Acquired Loans (Details) Note 2 - Acquisitions and Divestitures Pro Forma Infomation (Details) Loans held for Sale Loans held for sale Note 2 - Acquisitions and Divestitures - Divestitures (Details) Note 3 - Debt Securities - Securities Available-for-sale (Details) Note 3 - Debt Securities - Securities by Contractual Maturity (Details) Note 3 - Debt Securities - Securities Held to Maturity (Details) Granted (in dollars per share) us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue Note 3 - Debt Securities - Available For Sale Securities in Continuous Unrealized Loss Position (Details) us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss Securities available for sale, 12 months or longer, unrealized losses Vested (in dollars per share) us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss Securities available for sale, total unrealized losses Note 3 - Debt Securities - Held to Maturity Securities in Continuous Unrealized Loss Position (Details) Note 3 - Debt Securities - Gross Realized Gains and Losses from Sale of Available-for-sale Debt Securities (Details) Canceled (in dollars per share) US Treasury Securities [Member] us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue Nonvested shares at beginning of period (in dollars per share) Nonvested shares at end of period (in dollars per share) Note 4 - Loans - Loans by Class (Details) us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod Canceled (in shares) Note 4 - Loans - Covered Loans by Class (Details) Note 4 - Loans - PCI loans (Details) Note 4 - Loans - Activity in Accretable Yield on PCI loans (Details) us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber Nonvested shares at beginning of period (in shares) Nonvested shares at end of period (in shares) us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss Securities available for sale, less than 12 months, unrealized losses Note 5 - Credit Quality - Loans by Credit Quality (Details) Schedule of Derivative Instruments [Table Text Block] Other comprehensive income (loss) before reclassifications Note 5 - Credit Quality - Recorded Investment and Interest Income Recognized on Impaired Loans Excluding Purchased Credit Impaired Loans (Details) US Government Agencies Debt Securities [Member] us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent Reclassified from AOCI Note 5 - Credit Quality - Average Annual Recorded Investment and Interest Income Recognized on Impaired Loans Excluding Purchased Credit Impaired Loans (Details) Note 5 - Credit Quality - Information on Impaired PCI Loan Pools (Details) us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod Granted (in shares) Corporate Debt Securities [Member] Note 5 - Credit Quality - Nonaccrual Loans by Loan Class (Details) us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod Vested (in shares) Note 5 - Credit Quality - Aging of Past Due Loans by Loan Class (Details) Note 5 - Credit Quality - Loans Modified as Troubled Debt Restructurings by Loan Class and Accrual Status (Details) Note 5 - Credit Quality - Balance and Interest Income Related to Impaired Loan Pools (Details) Options exercisable at end of period Note 5 - Credit Quality - Loans Modified as Troubled Debt Restructurings (Details) Note 5 - Credit Quality - Other Real Estate Owned (Details) Note 6 - Allowance for Loan Losses - Changes in Allowance for Loan Losses (Details) Note 6 - Allowance for Loan Losses - Allowance for Loan Losses and Recorded Investment in Loans, Evaluated for Impairment Excluding PCI Loans, by Loan Class (Details) Note 6 - Allowance for Loan Losses - Allowance for Loan Losses on PCI Loans and Recorded Investment (Details) Options outstanding at end of period Note 7 - FDIC Indemnification Asset - Changes in Receivable From FDIC (Details) us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice Options exercisable at end of period (in dollars per share) Note 8 - Premises, Equipment, and Leases - Components of Premises and Equipment (Details) Options exercisable at end of period (Year) Note 8 - Premises, Equipment, and Leases - Minimum Lease Payments (Details) Note 9 - Goodwill and Other Intangible Assets - Changes in Goodwill, by Reporting Unit (Details) Note 9 - Goodwill and Other Intangible Assets - Components of Other Intangible Assets, by Reporting Unit (Details) Securities available for sale, total fair value us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value Note 9 - Goodwill and Other Intangible Assets - Estimated Amortization Expense for Intangible Assets, by Year (Details) Note 10 - Deposits - Components of Deposits (Details) Note 10 - Deposits - Scheduled Maturities of Time Deposits (Details) Options exercisable at end of period (in shares) Note 10 - Deposits - Scheduled Maturities of Certificates of Deposit of $250 Thousand or More (Details) Options outstanding at end of period (Year) Note 11 - Borrowings - Components of Borrowings (Details) Note 11 - Borrowings - Contractual Maturities of Repurchase Agreements (Details) Securities available for sale, less than 12 months, fair value Note 12 - Derivative Instruments and Hedging Activities - Notional or Contractual Amounts and Fair Values of Derivative Financial Instruments (Details) Securities available for sale, 12 months or longer, fair value Note 12 - Derivative Instruments and Hedging Activities - Effect of Derivative and Hedging Activity, on Consolidated Statements of Income (Details) Note 13 - Employee Benefit Plans - Schedule of Changes in Aggregate Actuarial Benefit Obligation (Details) Note 13 - Employee Benefit Plans - Components of Net Periodic Pension Cost and Assumed Discount Rate (Details) Note 13 - Employee Benefit Plans - Projected Benefit Payments (Details) Note 13 - Employee Benefit Plans - Pre-tax Compensation Expense and Excess Tax Benefit Recognized in Earnings (Details) Note 13 - Employee Benefit Plans - Stock Option Activity (Details) Note 13 - Employee Benefit Plans - Restricted Stock Activity (Details) Note 14 - Other Operating Income and Expense - Components of Other Operating Income and Expense (Details) Financial Instruments [Domain] Note 15 - Income Taxes - Components of Income Tax Provision (Details) us-gaap_LoansAndLeasesReceivableRelatedPartiesProceeds Loan repayments Note 15 - Income Taxes - Reconciliation of Statutory Federal Tax Rate and Effective Tax Rate From Continuing Operations (Details) us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice Options outstanding at beginning of period (in dollars per share) Options outstanding at end of period (in dollars per share) Note 15 - Income Taxes - Significant Components of Net Deferred Tax Asset (Details) Note 16 - Accumulated Other Comprehensive Income - Components of Accumulated Other Comprehensive Income, Net of Tax (Details) Note 16 - Accumulated Other Comprehensive Income - Reclassifications Out of Accumulated Other Comprehensive Income (Loss) (Details) us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice Canceled (in dollars per share) Note 17 - Fair Value - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) Note 17 - Fair Value - Changes in Level 3 Fair Value Measurements (Details) Financial Instrument [Axis] New loans and advances Note 17 - Fair Value - Assets Measured at Fair Value on Nonrecurring Basis (Details) Note 17 - Fair Value - Quantitative Information for Assets Measured at Fair Value on Nonrecurring Basis (Details) Note 17 - Fair Value - Financial Instruments (Details) us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice Granted (in dollars per share) Note 18 - Earnings Per Share - Basic and Diluted Earnings Per Common Share (Details) Securities available for sale, no single maturity date, fair value us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice Exercised (in dollars per share) Note 19 - Related Party Transactions - Changes in Loans With Related Parties (Details) Note 20 - Litigation, Commitments, and Contingencies - Off-balance Sheet Financial Instruments (Details) Note 21 - Regulatory Requirements and Restrictions - Company's and Bank's Capital Ratios (Details) Note 22 - Parent Company Financial Information - Condensed Balance Sheets (Details) Note 22 - Parent Company Financial Information - Condensed Statements of Income (Details) Note 22 - Parent Company Financial Information - Condensed Statements of Cash Flows (Details) Note 23 - Quarterly Financial Data (Unaudited) - Summary of Quarterly Earnings (Details) Securities available for sale, no single maturity date, amortized cost us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost Notes To Financial Statements Notes To Financial Statements [Abstract] us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber Options outstanding at beginning of period (in shares) Options outstanding at end of period (in shares) Loans, Notes, Trade and Other Receivables Disclosure [Text Block] us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodAtAcquisitionAtFairValue Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Acquired During Period, at Acquisition, at Fair Value Allowance for Credit Losses and Recorded Investment in Loans by Segment and Class [Table Text Block] Tabular disclosure of allowance for credit losses and recorded investment in loans by segment and class. us-gaap_PolicyTextBlockAbstract Accounting Policies us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodContractuallyRequiredPaymentsReceivableAtAcquisition Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Acquired During Period, Contractually Required Payments Receivable at Acquisition Gross realized gains us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYield Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Ending Balance Beginning balance Ending balance us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant us-gaap_DebtSecuritiesAvailableForSaleRealizedLoss Gross realized losses Reclassifications from nonaccretable difference(1) Schedule of Information Related to Purchased Credit Impaired Loans [Table Text Block] Tabular disclosure of information related to purchased credit impaired loans. us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAccretion Accretion Waccamaw Commercial [Member] Information pertaining to Waccamaw Commercial loans. Waccamaw Serviced Home Equity Lines [Member] Information pertaining to Waccamaw serviced home equity lines. PCI loans, unpaid principal balance Allowance for Credit Losses [Text Block] Waccamaw Residential [Member] Information pertaining to Waccamaw residential loans. PCI loans, recorded investment Peoples Commercial [Member] Information pertaining to Peoples Commercial loans. Other Commercial Loan [Member] Information pertaining to other commercial loans. us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1 Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Allowance for acquired impaired loans Represents the amount of allowance for acquired impaired loans. FDIC Loss Share Agreement Receivable [Text Block] Entire disclosure of FDIC loss share agreement. Peoples Residential [Member] Information pertaining to Peoples residential loans. us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage Acquired impaired loans evaluated for impairment Represents the amount of acquired impaired loans evaluated for impairment. Liabilities fcbc_PercentageOfLossCoveredByFDIC Percentage of Loss Covered by FDIC Represents the percentage of loss covered by the FDIC. Reimbursable expenses to the FDIC Amount of increases to the indemnification asset due to acquisitions of assets relating reimbursable expenses accrued with the Federal Deposit Insurance Corporation (FDIC). Vesting [Axis] Vesting [Domain] Share-based Payment Arrangement, Tranche One [Member] Total assets Total assets Below Market Interest Rate and Extended Payment Term [Member] Information pertaining to below market interest rates and extended payment terms. Unsecured Line of Credit [Member] Information pertaining to the unsecured line of credit. Plan Name [Axis] Plan Name [Domain] Below Market Interest Rate [Member] Information pertaining to below market interest rates. Compensation and Employee Benefit Plans [Text Block] us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions Share-based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount Wholesale Repurchase Agreements [Member] Information pertaining to wholesale repurchase agreements. us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions Share-based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount fcbc_IssuanceOfCommonStockTo401kPlan Issuance of common stock to 401(k) plan Represents issuance of common stock to 401(k) plan. us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1 Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Retail Repurchase Agreements [Member] Information pertaining to retail repurchase agreements. Weighted average rate fcbc_WeightedAverageContractualRate Represents the weighted average contractual rate. Reclassification from Loans Collectively Evaluated for Impairment to Loans Individually Evaluated for Impairment [Member] Represents amounts reclassified from loans collectively evaluated for impairment to loans individually evaluated for impairment. Maturity Overnight and Continuous [Member] Maturity period of the day after the reporting date and continuous for repurchase agreements and similar transactions, for example, but not limited to, securities lending arrangements. Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block] Adjustments for Error Corrections [Axis] Other assets Adjustments for Error Correction [Domain] Award Type [Domain] Award Type [Axis] us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization Accumulated amortization us-gaap_FiniteLivedIntangibleAssetsNet Total estimated amortization expense Finite-lived intangible assets, net Other intangible assets Interest and Fees on Loans [Member] Primary financial statement caption encompassing interest and fees on loans. Directors' Plan [Member] Information pertaining to the Directors' Supplemental Retirement Plan (the Directors' Plan"). Finite-lived intangible assets, gross Deferred compensation liabilities Deferred compensation liabilities Fair value portion of deferred compensation liabilities. Deferred compensation assets Deferred compensation assets Fair value portion of deferred compensation assets. Commitments and Contingencies Disclosure [Text Block] us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment Accumulated depreciation and amortization Impaired Loans [Member] Information pertaining to impaired loans. Premises and equipment, net Total premises and equipment, net Goodwill Goodwill Balance Balance Bank Time Deposits [Member] OREO [Member] Information pertaining to other real estate owned (OREO). us-gaap_PropertyPlantAndEquipmentGross Total premises and equipment Land Buildings and leasehold improvements Equipment Reserve for unfunded commitments Represents the amount of reserve for unfunded credit commitments. Allowance for loan losses related to TDRs Represents the amount of allowance for loan losses. us-gaap_OtherPostretirementBenefitExpense Other Postretirement Benefits Cost (Reversal of Cost) Derivative assets Derivative assets Derivative Instrument [Axis] Derivative Contract [Domain] us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueAmount Equity Securities without Readily Determinable Fair Value, Amount Securities available for sale Debt securities available for sale Securities available for sale, fair value Debt securities held to maturity Total amortized cost Securities held to maturity, amortized cost Equity securities us-gaap_EquitySecuritiesFvNi Investment in subsidiaries Income before income taxes and equity in undistributed net income of subsidiaries Income tax expense Total income tax expense Income tax benefit Residential real estate loans in the foreclosure process(1) us-gaap_OtherExpenses Other(1) Unrealized gains on available for sale securities Amount of deferred tax liability attributable to taxable temporary differences from unrealized gains on available-for-sale securities. After five years through ten years us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsNetCarryingAmount After ten years us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent One year or less us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount After one year through five years us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsNetCarryingAmount Interest-bearing deposits in banks One year or less us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue After one year through five years us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue After five years through ten years us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue us-gaap_CashAndCashEquivalentsAtCarryingValue Cash and cash equivalents at beginning of period Cash and cash equivalents at end of period After ten years us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss Securities held to maturity, unrealized losses Securities held to maturity, unrealized gains Salaries and employee benefits Cash and due from banks Telephone and data communications us-gaap_DefinedBenefitPlanBenefitObligation Beginning balance Ending balance us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter 2025 through 2029 Community Banking [Member] Represents the community banking reporting unit. us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo 2021 us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree 2022 Acquisitions and dispositions, net Represents the net of goodwill acquired and disposed of during period. us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour 2023 us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive 2024 Amendment Flag Scheduled Maturities of Certificates of Deposits, Greater than 250,000 [Table Text Block] Tabular disclosure of time deposit liabilities of 250,000 or more. Three months or less Amount of time deposit liabilities, including certificates of deposit, in denominations of $250,000 or more, maturing within three months or fewer from the balance sheet date. FDIC Indemnification Asset Roll Forward [Table Text Block] us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths 2020 Use of Estimates, Policy [Policy Text Block] Over twelve months Amount of time deposit liabilities, including certificates of deposit, in denominations of $250,000 or more, maturing after twelve months from the balance sheet date. New Accounting Pronouncements, Policy [Policy Text Block] fcbc_DefinedBenefitPlanEmployeeContributionAge Defined Benefit Plan, Employee Contribution, Age Represents the employee contribution age for defined benefit plan. Over three through six months Amount of time deposit liabilities, including certificates of deposit, in denominations of $250,000 or more, maturing within three to six months after the balance sheet date. Over six through twelve months Amount of time deposit liabilities, including certificates of deposit, in denominations of $250,000 or more, maturing within six to twelve months after the balance sheet date. Reclassification, Policy [Policy Text Block] fcbc_DefinedContributionPlanMaximumEmployeeContributionAsPercentageOfBaseSalary Defined Contribution Plan, Maximum Employee Contribution as Percentage of Base Salary Represents the maximum percentage of base salary the employee contribution. us-gaap_GainLossOnSaleOfPropertyPlantEquipment Gain on sale of premises and equipment, net fcbc_StoplossInsuranceLiabilityForAggregateClaims Stop-loss Insurance Liability for Aggregate Claims Amount of stop-loss insurance coverage for aggregate claims. fcbc_StoplossInsuranceLiabilityForIndividualClaims Stop-loss Insurance Liability for Individual Claims Amount of stop-loss insurance coverage for individual claims. Securities held to maturity, total fair value fcbc_DefinedBenefitPlanEmployerMatchingContributions Defined Benefit Plan, Employer Matching Contributions Amount of employer matching contributions to the plan. Current Fiscal Year End Date us-gaap_DebtAndEquitySecuritiesRealizedGainLoss Loss on sale of securities fcbc_SharebasedCompensationArrangementBySharebasedPaymentAwardMaximumExercisePeriod Share-based Compensation Arrangement By Share-based Payment Award, Maximum Exercise Period Period from grant date that an equity-based award can be exercised, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Securities held to maturity, less than 12 months fair value 401 (k) Savings Plan [Member] Represents the company's 401K savings plan. Assumed discount rate Securities held to maturity, 12 months or longer fair value Basis of Accounting [Text Block] us-gaap_DebtSecuritiesAvailableForSaleRealizedGainLoss Net loss on sale of securities Interest receivable Document Fiscal Period Focus 2012 Omnibus Incentive Compensation Plan [Member] Represents the 2012 Omnibus Incentive compensation plan. Document Fiscal Year Focus Consolidation, Policy [Policy Text Block] Document Period End Date Tier 1 Leverage, actual ratio Tier 1 Leverage, required ratio Entity Emerging Growth Company Tier 1 Leverage, to be well capitalized ratio Document Type us-gaap_GainsLossesOnExtinguishmentOfDebt Loss on extinguishment of debt us-gaap_InvestmentOwnedAtCost Investment Owned, at Cost Total risk-based capital, to be well capitalized ratio Entity Small Business Litigation settlements Entity Shell Company Common equity Tier 1, actual ratio Document Information [Line Items] Document Information [Table] Total risk-based capital, actual ratio Total risk-based capital, required ratio Entity Public Float us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid Benefits paid Entity Filer Category Tier 1 risk-based capital, actual ratio Entity Current Reporting Status Tier 1 risk-based capital, required ratio Entity Voluntary Filers Merger expense Business Combination, Acquisition Related Costs Tier 1 risk-based capital, to be well capitalized ratio Entity Well-known Seasoned Issuer Total risk-based capital ratio, actual amount fcbc_PercentageOfOperatingIncome Percentage of Operating Income Represents the percentage of operating income that other components cannot exceed. Plan change Total risk-based capital ratio, required amount us-gaap_DefinedBenefitPlanActuarialGainLoss Actuarial loss (gain) Total risk-based capital to be well capitalized, amount fcbc_OtherMiscellaneousIncome Other(1) Amounts of all other miscellaneous income not separately disclosed. us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss Securities held to maturity, 12 months or longer unrealized losses Writedowns of property, plant & equipment Tier 1 Leverage ratio, actual amount Goodwill impairment Goodwill, Impairment Loss Impairment charges fcbc_IncomeTaxReconciliationFederalStateAndLocalIncomeTaxes Total effective income tax rate reconciliation, amount Amount 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 domestic, state, and local income tax expense. Tier 1 Leverage ratio, required amount Tier 1 Leverage to be well capitalized, amount us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss Securities held to maturity, less than 12 months unrealized losses Debt Securities, Held-to-maturity [Table Text Block] Common equity Tier 1 ratio, actual amount Statement of Comprehensive Income [Abstract] Common equity Tier 1 ratio, required amount us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf Impairment of Long-Lived Assets to be Disposed of Common equity Tier 1 to be well capitalized, amount Entity Central Index Key Tier 1 risk-based capital ratio, actual amount Entity Registrant Name Tier 1 risk-based capital ratio, required amount fcbc_EffectiveIncomeTaxRateReconciliationFederalStateAndLocalIncomeTaxes Total effective income tax rate reconciliation 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 applicable to domestic, state, and local income taxes. Tier 1 risk-based capital to be well capitalized, amount Entity [Domain] Legal Entity [Axis] Amortization of intangible assets Amortization of intangibles Amortization of Intangible Assets, Total Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table Text Block] FDIC indemnification asset Beginning balance Ending balance Regulatory Capital Requirements under Banking Regulations [Text Block] Other real estate owned (includes covered OREO of $0 and $32, respectively) Total OREO Covered OREO Other real estate owned, covered us-gaap_OtherRevenueExpenseFromRealEstateOperations OREO expense and net loss Non-covered OREO us-gaap_OtherRealEstateNonCovered Entity Common Stock, Shares Outstanding (in shares) Depreciation and amortization of premises and equipment FDIC assisted transactions Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from Federal Deposit Insurance Company (FDIC) transactions. fcbc_DeferredTaxLiabilitiesFederalDepositInsuranceCompanyTransaction FDIC indemnification asset Amount of deferred tax liability attributable to taxable temporary differences from Federal Deposit Insurance Company (FDIC) transactions. Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Purchase accounting Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from purchase accounting. Advertising and public relations us-gaap_LoansAndLeasesReceivableNetReportedAmountCoveredAndNotCovered Loans held for investment, net Professional fees Non-covered loans Non-covered us-gaap_LoansAndLeasesReceivableAllowance Loans and Leases Receivable, Allowance, Ending Balance Allowance for loan losses Beginning balance Ending balance Investments [Domain] Trading Symbol Office supplies Occupancy expense Investment Type [Axis] fcbc_CapitalConservationBuffer Capital Conservation Buffer An additional amount held in risk-based capital designed to ensure that banks build up capital buffers outside periods of stress which can be drawn down as losses are incurred. The requirement is based on simple capital conservation rules designed to avoid breaches of minimum capital requirements. us-gaap_TableTextBlock Notes Tables fcbc_CapitalConservationBufferPhaseInAmount Capital Conservation Buffer Phase In Amount Amount resulting from the phase-in of a capital conservation buffer. Related Parties [Member] Represents related parties. us-gaap_GainLossOnSaleOfOtherAssets Provision expense and loss on sale of other real estate owned fcbc_TierOneCapitalSecuritiesPhaseOutPeriod Tier One Capital Securities Phase Out Period Represents the phase out period for Tier 1 capital securities. Common equity Tier 1, to be well capitalized ratio The Common Equity Tier 1 Risk Based 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 1, required ratio The minimum Common Equity Tier 1 Risk Based Capital Ratio (Common Equity Tier 1 Capital divided by risk-weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action. Noninterest income, excluding net gain (loss) on sale of securities Amount of other operating income excluding gains (losses) on sale of securities. Covered loans Loans held for investment, covered Securities held to maturity, fair value Total fair value us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledged1 Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged us-gaap_CashCashEquivalentsAndFederalFundsSold Total cash and cash equivalents Other operating expense Total other operating expense Federal funds sold Derivative Instruments, Gain (Loss) [Table Text Block] Interest expense Total interest expense Common Dividend [Member] Represents the common dividend. Special Cash Dividend [Member] Represents the special cash dividend. Highlands Bankshares, Inc. [Member] Represents Highlands Bankshares, Inc. us-gaap_DisclosureTextBlockAbstract Notes to Financial Statements Derivative Instruments and Hedging Activities Disclosure [Text Block] Interest on long-term debt fcbc_BusinessCombinationStockConversionRatio Business Combination, Stock Conversion Ratio The stock conversion ratio for a business combination. Interest on short-term borrowings Fair Value Adjustments [Member] Represents the fair value adjustments. Loans held for investment, net of allowance and mark fcbc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLoansHeldForInvestmentNetOfAllowanceAndMark Loans acquired at fair value The amount of loans held for investment, net of allowance and mark recognized as of the acquisition date. fcbc_DeferredLoanFeesExcludedFromFairValueAdjustmentOfAcquiredLoan Deferred Loan Fees Excluded from Fair Value Adjustment of Acquired Loan The amount of deferred loan fees that excluded from the fair value adjustment of acquired loan. fcbc_AcquiredLoanFairValueAdjustments Acquired Loan, Fair Value Adjustments The increase (decrease) to acquired loan related to the fair value adjustments. us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive 2025 and thereafter fcbc_ReserveForUnfundedCommitmentsFairValueAdjustment Reserve for Unfunded Commitments, Fair Value Adjustment The increase (decrease) to reserve for unfunded commitments related to the fair value adjustment. fcbc_LeaseLiabilityFairValueAdjustment Lease Liability, Fair Value Adjustment The increase (decrease) to lease liability related to the fair value adjustment. fcbc_DeathBenefitsPayableFairValueAdjustment Death Benefits Payable, Fair Value Adjustment The increase (decrease) to death benefits payable related to the fair value adjustment. us-gaap_DeferredCompensationArrangementWithIndividualCompensationExpense Deferred Compensation Arrangement with Individual, Compensation Expense Fair Value Measurement, Policy [Policy Text Block] us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo 2021 Interest on deposits Interest-bearing fcbc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInterestBearingDeposits Amount of interest-bearing deposits assumed at the acquisition date. us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree 2022 Noninterest-bearing fcbc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoninterestBearingDeposits Amount of noninterest-bearing deposits assumed at the acquisition date. us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour 2023 Other real estate fcbc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherRealEstate The amount of other real estate recognized as of the acquisition date. us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive 2024 Loans held for sale fcbc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLoansHeldForSale The amount of loans held for sale recognized as of the acquisition date. us-gaap_DeferredCompensationArrangementWithIndividualRecordedLiability Deferred Compensation Arrangement with Individual, Recorded Liability Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths 2020 Recorded by Acquiree [Member] The values recorded by the acquiree. us-gaap_FiniteLivedIntangibleAssetsRemainingAmortizationPeriod1 Finite-Lived Intangible Assets, Remaining Amortization Period Construction and Land Development [Member] Represents construction and land development. 1-4 family, Senior-commercial [Member] Represents the 1-4 family, senior-commercial. Business Combinations Policy [Policy Text Block] us-gaap_FiniteLivedIntangibleAssetUsefulLife Finite-Lived Intangible Asset, Useful Life Earnings Per Share, Policy [Policy Text Block] Commercial Real Estate Non-owner Occupied [Member] Represents commercial real estate- non-owner occupied. Commercial Real Estate-owner Occupied [Member] Represents commercial real estate-owner occupied. Interest expense: Multifamily [Member] Represents multifamily. Farmland and Other Agricultural [Member] Represents farmland and other agricultural. Lease Acquired from Acquisition [Member] Represents the lease that acquired from a business acquisition. fcbc_LesseeOperatingLeaseRemainingLeaseTerm Lessee Operating Lease Remaining Lease Term Remaining lease term of operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. 1-4 Family, Senior-consumer [Member] Represents 1-4 family, senior-consumer. 1-4 Family, Junior and HELOCS [Member] Represents 1-4 family, junior and HELOCS. Income Tax, Policy [Policy Text Block] Cash dividends received from subsidiary bank Interest income Total interest income Reclassification of certain tax effects fcbc_ReclassificationFromAociForStrandedTaxCurrentPeriodNetOfTaxAttributableToParent Amount after tax of reclassification adjustments for stranded tax of other comprehensive income (loss) attributable to parent. Interest on deposits in banks Highlands [Member] Represents loans acquired from Highlands. Schedule of Finite-Lived Intangible Assets [Table Text Block] us-gaap_LesseeOperatingLeaseTermOfContract Lessee, Operating Lease, Term of Contract Purchase price per share of the Company's common stock (in dollars per share) us-gaap_SharesIssuedPricePerShare Share-based Payment Arrangement [Policy Text Block] us-gaap_TimeDepositMaturitiesYearFour 2023 us-gaap_TimeDepositMaturitiesYearFive 2024 us-gaap_TimeDepositMaturitiesAfterYearFive 2025 and thereafter Interest on securities -- taxable Interest on securities -- tax-exempt us-gaap_TimeDepositMaturitiesYearOne 2020 us-gaap_TimeDepositMaturitiesYearTwo 2021 us-gaap_TimeDepositMaturitiesYearThree 2022 Advertising Cost [Policy Text Block] Time Deposit Maturities [Table Text Block] Interest and fees on loans us-gaap_DepositLiabilitiesCollateralIssuedFinancialInstruments Deposit Liabilities, Collateral Issued, Financial Instruments Revenue from Contract with Customer [Policy Text Block] us-gaap_DeferredTaxAssetsValuationAllowance Deferred Tax Assets, Valuation Allowance, Total us-gaap_DeferredTaxAssetsNet Total deferred tax assets Interest income: Individual retirement accounts us-gaap_DeferredTaxAssetsLiabilitiesNet Net deferred tax asset Money market accounts us-gaap_DeferredTaxAssetsOther Other Savings deposits Goodwill and Intangible Assets, Policy [Policy Text Block] Certificates of deposit us-gaap_DeferredIncomeTaxLiabilities Total deferred tax liabilities Interest-bearing demand deposits Other operating income Total noninterest income Noninterest income Unrealized losses on available-for-sale securities us-gaap_TimeDepositsAtOrAboveFDICInsuranceLimit Time Deposits, at or Above FDIC Insurance Limit Total contractual maturities us-gaap_BankOwnedLifeInsuranceIncome Bank owned life insurance Deposit Liabilities Disclosures [Text Block] Intangible assets Unrealized asset losses Noninterest income: Deferred loan fees Fully Phased-In [Member] Represents the fully phased in minimum Basel III requirements. Provision for loan losses Provision for loan losses Net interest income after provision Net interest income after provision for loan losses Provision for (Recovery of) loan losses charged to operations Provision for Loan and Lease Losses, Total us-gaap_PropertyPlantAndEquipmentUsefulLife Property, Plant and Equipment, Useful Life Net interest income Net interest income Schedule of Underlying Assets of Repurchase Agreements when Amount of Repurchase Agreements Exceeds 10 Percent of Assets [Table Text Block] Other income Allowance for loan losses us-gaap_NumberOfOperatingSegments Number of Operating Segments Furniture and Fixtures [Member] us-gaap_NumberOfReportableSegments Number of Reportable Segments Building and Building Improvements [Member] us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeCompensation Deferred compensation assets Land Improvements [Member] Property, Plant and Equipment, Policy [Policy Text Block] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Deposit Account [Member] Federal net operating loss carryforward Assets Net cash used in financing activities Net cash used in financing activities us-gaap_OtherOperatingIncome Total other operating income Net cash provided by operating activities Net cash provided by operating activities Other Net cash provided by investing activities Net cash provided by investing activities Net increase (decrease) in cash and cash equivalents Net increase (decrease) in cash and cash equivalents Derivatives, Policy [Policy Text Block] Odd days interest deferral Repurchase Agreements, Collateral, Policy [Policy Text Block] fcbc_SalesPriceInExcessOfNetLiabilitiesAssumed Sales price in excess of net liabilities assumed Represents the sales price in excess of the net liabilities assumed in an acquisition. Net change in other financing activities Marketable Securities, Policy [Policy Text Block] Impaired loans, related allowance Fixed assets Impaired loans with no related allowance, interest income recognized Impaired loans with a related allowance, interest income recognized Interest income recognized us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod Interest income recognized Impaired loans with no related allowance, recorded investment us-gaap_PaymentsOfDividendsCommonStock Payments of common stock dividends Impaired loans with a related allowance, recorded investment Total impaired loans, recorded investment Impaired Financing Receivable, Recorded Investment, Total Average recorded investment Impaired loans with no related allowance, average recorded investment Impaired loans with a related allowance, average recorded investment Total impaired loans, average recorded investment us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment Total sales price fcbc_PaymentsForProceedsFromDivestitureOfBusinesses The cash outflow or inflow associated with the amount paid or received from the sale of a portion of the company's business, for example a segment, division, branch or other business, during the period. Amount due remaining on books fcbc_ReceivableDueFromPayableDueToDivestitureOfBusinesses Amount of receivable due from or payable due to as part of consideration transferred in a divestiture of business. Impaired loans with no related allowance, unpaid principal balance Impaired loans with a related allowance, unpaid principal balance Net cash received in divestitures fcbc_PaymentsForProceedsFromDivestitureOfBusinessesNetOfCashDivested The cash outflow or inflow associated with the divestiture of businesses, net of cash divested. Total impaired loans, unpaid principal balance Book value of assets sold fcbc_DisposalGroupIncludingDiscontinuedOperationAssetsSoldAcquired Amount classified as assets sold (acquired) attributable to disposal group held for sale or disposed of. us-gaap_OtherNoninterestExpense Other operating expense Noninterest expense Total noninterest expense Payments for repurchase of common stock Payments for repurchase of common stock Book value of liabilities sold fcbc_DisposalGroupIncludingDiscontinuedOperationLiabilitiesSoldIncurred Amount classified as liabilities sold (incurred) attributable to disposal group held for sale or disposed of us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiability Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability Furniture and equipment expense Scenario [Domain] FDIC premiums and assessments Proceeds from stock options exercised State Proceeds from issuance of common stock us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit State Scenario [Axis] Noninterest expense: Federal us-gaap_DeferredFederalIncomeTaxExpenseBenefit Federal us-gaap_CurrentIncomeTaxExpenseBenefit Total current tax expense Class of Financing Receivable [Domain] Class of Financing Receivable [Axis] Financing Receivable Portfolio Segment [Domain] Commercial Portfolio Segment [Member] Income before income taxes Income before income taxes Income before income taxes Reclassification out of Accumulated Other Comprehensive Income [Member] Financing Receivable Portfolio Segment [Axis] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Domain] Comprehensive Income (Loss) Note [Text Block] Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Reclassification out of Accumulated Other Comprehensive Income [Table Text Block] Insurance commissions Repayments of FHLB and other borrowings, net Loans and Leases Receivable, Allowance for Loan Losses Policy [Policy Text Block] us-gaap_RepaymentsOfLongTermDebt Repayments of long-term debt Financing Receivable, Held-for-investment [Policy Text Block] Cash and Cash Equivalents, Policy [Policy Text Block] Accounting Policies [Abstract] Basis of Accounting, Policy [Policy Text Block] fcbc_EffectiveIncomeTaxRateReconciliationAdjustmentFromBankOwnedLifeInsurancePercent Bank owned life insurance 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 bank owned life insurance expense. fcbc_EffectiveIncomeTaxRateReconciliationAdjustmentFromBankOwnedLifeInsuranceAmount Bank owned life insurance, amount Amount 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 bank owned life insurance expense. Cash dividends per common share (in dollars per share) Common dividends declared, per share (in dollars per share) Reclassifications Reflects the amount of reclassification made to related parties in the form of loan and lease receivables. fcbc_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeExpenseAccrualMethod Impaired loans with a related allowance, interest income recognized Amount of interest income (expense), recognized on accrual basis, on financing receivables, for which there is a related allowance for credit losses and are recognized as impaired. Loans originated to finance other real estate Value of loans originated to finance other real estate owned. Receivable Type [Axis] Receivable [Domain] Condensed Financial Information of Parent Company Only Disclosure [Text Block] Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Equity in (dividends in excess) of undistributed net income of subsidiaries This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. This item includes dividends in excess of income or expense related to stock-based compensation based on the investor's grant of stock to employees of an equity method investee. Total dilutive effect of potential common shares (in shares) Interest, taxes, and other liabilities The aggregate amount of interest, taxes and other liabilities. fcbc_ExcessTaxBenefitFromSharebasedCompensation Excess tax benefit Amount of realized tax benefit related to deductible compensation cost reported on the entity's tax return for equity instruments in excess of the compensation cost . Designated Par Value [Member] Information pertaining to preferred stock with a designated par value. us-gaap_DueToOtherRelatedPartiesCurrentAndNoncurrent Due to Other Related Parties Antidilutive potential common shares (in shares) Undesignated Par Value [Member] Information pertaining to preferred stock with an undesignated par value. Weighted average diluted shares outstanding (in shares) Diluted (in shares) Weighted average common shares outstanding, diluted (in shares) Asset Class [Axis] Asset Class [Domain] Statement of Financial Position [Abstract] Diluted (in dollars per share) Diluted earnings per common share (in dollars per share) Weighted average common shares outstanding, basic (in shares) Basic (in shares) Other items, net Income tax at the effective tax rate us-gaap_EffectiveIncomeTaxRateContinuingOperations Business Acquisition [Axis] Basic (in dollars per share) Basic earnings per common share (in dollars per share) Business Acquisition, Acquiree [Domain] Deferred tax revaluation Statement of Cash Flows [Abstract] Statement of Stockholders' Equity [Abstract] us-gaap_EffectiveIncomeTaxRateReconciliationTaxExemptIncome Tax-exempt interest income Repayments of securities sold under agreements to repurchase, net Proceeds from (Payments for) in Securities Sold under Agreements to Repurchase Financing Receivable, Nonaccrual [Table Text Block] Quarterly Financial Information [Table Text Block] Fiduciary and Trust [Member] First Community Bankshares, Inc. common (in shares) us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued fcbc_AccretionOnAcquiredLoans Accretion on acquired loans Amount of accretion on acquired loans. Amortization of FDIC indemnification asset, net Net FDIC indemnification asset amortization Increases (decreases) to the indemnification asset due to accretion (amortization) of the loan discount relating to loss sharing agreements with the Federal Deposit Insurance Corporation (FDIC). Investments Classified by Contractual Maturity Date [Table Text Block] Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] (Payments to) proceeds from the FDIC Amount of cash inflow from Federal Deposit Insurance Corporation. Nondeductible goodwill impairment and disposition First Community Bank [Member] Information pertaining to First Community Bank. Realized Gain (Loss) on Investments [Table Text Block] Schedule of Available-for-sale Securities Reconciliation [Table Text Block] (Decrease) increase in interest-bearing deposits, net Increase in noninterest-bearing deposits, net Loans to affiliates us-gaap_LoansAndLeasesReceivableRelatedParties Beginning balance Ending balance State income tax, net of federal benefit Fair Value Measurements, Nonrecurring [Table Text Block] Total deposits fcbc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeposits Amount of deposits assumed at the acquisition date. Other items, net, amount Financing activities Federal income tax at the statutory rate Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Deferred tax revaluation, amount Dividends in excess of undistributed net income of subsidiaries fcbc_PercentageOfCombinedDepreciationOfCombinedReportedValueOfAggregateSecuritiesPortfolio Percentage of Combined Depreciation of Combined Reported Value of Aggregate Securities Portfolio Represents the percentage of combined depreciation of combined reported value of aggregate securities portfolio. us-gaap_IncomeTaxReconciliationTaxExemptIncome Tax-exempt interest income, amount fcbc_NumberOfSecuritiesInUnrealizedLossPosition Number of Securities in Unrealized Loss Position Represents the number of securities in unrealized loss position. Proceeds from bank owned life insurance Dividends [Axis] Mortgage-backed Agency Securities [Member] Information pertaining to mortgage-backed agency securities. Dividends [Domain] Single Issue Trust Preferred Securities [Member] Information pertaining to single issue trust preferred securities. us-gaap_PaymentsForProceedsFromBusinessesAndInterestInAffiliates Cash proceeds from mergers, acquisitions, and divestitures, net Net identifiable assets acquired over (under) liabilities assumed us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet Net assets acquired over liabilities assumed us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet Cash sold us-gaap_CashDivestedFromDeconsolidation Total liabilities us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities Other liabilities us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther Long term debt us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesLongTermDebt Nondeductible goodwill impairment and disposition, amount Class of Stock [Axis] Class of Stock [Domain] Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Total assets us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets Financial Service, Other [Member] State income tax, net of federal benefit, amount Premises and equipment us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment Other assets us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets Intangible assets us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill Notional or contractual amount Federal income tax at the statutory rate, amount Securities available for sale us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsMarketableSecurities Income Tax Disclosure [Text Block] Cash and cash equivalents us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents Hedging Designation [Axis] Hedging Designation [Domain] Designated as Hedging Instrument [Member] Schedule of Debt [Table Text Block] Fair Value of Company common stock issued us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable Fair Value of total consideration transferred us-gaap_BusinessCombinationConsiderationTransferred1 Business Combination, Consideration Transferred, Total 2024 and thereafter fcbc_LesseeOperatingLeaseLiabilityPaymentsDueInRollingYearFiveAndAfter Amount of lessee's undiscounted obligation for lease payments for operating lease, due in the fifth and after rolling twelve months following latest statement of financial position date. For interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date. Schedule of Loans Acquired [Table Text Block] Tabular disclosure of loans acquired during the period. Share-based Payment Arrangement, Option, Activity [Table Text Block] Pass [Member] Share-based Payment Arrangement, Restricted Stock Unit, Activity [Table Text Block] Proceeds from maturities and calls of securities held to maturity Internal Credit Assessment [Axis] Proceeds from maturities, prepayments, and calls of securities available for sale Internal Credit Assessment [Domain] Schedule of Net Benefit Costs [Table Text Block] Net adjusted income available to the common shareholder Schedule of Net Funded Status [Table Text Block] Proceeds from sale of other real estate owned Business Acquisition, Pro Forma Information [Table Text Block] Schedule of Expected Benefit Payments [Table Text Block] Total revenues (net interest income plus noninterest income) Cash paid for fractional shares fcbc_BusinessCombinationCashPaidForFractionalShares The amount of cash paid for fractional shares in a business combination. us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt Payments to acquire securities available for sale Construction, Development and Other Land [Member] Information pertaining to construction, development and other land loans. Schedule of Held to Maturity Debt Securities [Table Text Block] Tabular disclosure held to maturity debt securities. Single Family Non-owner Occupied [Member] Information pertaining to single family non-owner occupied loans. Non-farm, Non-residential [Member] Information pertaining to non-farm, non-residential loans. Commercial and Industrial [Member] Information pertaining to commercial and industrial loans. Multi-family Residential [Member] Information pertaining to multi-family residential loans. Farmland [Member] Information pertaining to farmland loans. Consumer Real Estate Portfolio Segment [Member] Portfolio segment of the company's total financing receivables related to consumer real estate receivables. Agricultural [Member] Information pertaining to agricultural loans. Goodwill and Intangible Assets Disclosure [Text Block] Schedule of Goodwill [Table Text Block] Home Equity Lines [Member] Information pertaining to home equity lines. Single Family Owner Occupied [Member] Information pertaining to single family owner occupied loans. Owner Occupied Construction [Member] Information pertaining to owner occupied construction. Other Loan [Member] Information pertaining to other loans. Consumer and Other Portfolio Segment [Member] Portfolio segment of the company's total financing receivables related to consumer and other receivables. Consumer Loans [Member] Information pertaining to consumer loans. Proceeds from sale of premises and equipment Retirement Plan Type [Axis] Service fees The amount of service fees during the period. Retirement Plan Type [Domain] Credit Facility [Axis] Credit Facility [Domain] Supplemental Employee Retirement Plan [Member] Special Mention [Member] Substandard [Member] Doubtful [Member] Increase (decrease) in accumulated other comprehensive loss Represents the increase (decrease) in accumulated other comprehensive income in noncash investing or financing activities. Unlikely to be Collected Financing Receivable [Member] Federal Deposit Insurance Corporation Indemnification Asset [Policy Text Block] Disclosure of accounting policy for indemnification assets relating to loss share agreements with the Federal Deposit Insurance Corporation (FDIC). us-gaap_PaymentsToAcquireProductiveAssets Payments to acquire premises and equipment Common stock issued in acquisition Other Intangible Assets [Member] Dilutive effect of potential common shares (in shares) Transfer of loans to other real estate TDRs Financing Receivable, Troubled Debt Restructuring Weighted average shares outstanding Cash paid for income taxes Net loss on sale of securities Net gain (loss) on sale of securities Total contracts, payment default Pre-modification recorded investment Post-modification recorded investment Supplemental disclosure -- cash flow information Recorded investment, payment default Payment Deferral [Member] Total contracts Loan Restructuring Modification [Axis] Loan Restructuring Modification [Domain] us-gaap_OperatingLeaseExpense Operating Lease, Expense Impaired Financing Receivables [Table Text Block] Financing Receivable, Troubled Debt Restructuring [Table Text Block] Core Deposits [Member] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Total loans Loans held for investment, net of unearned income (includes covered loans of $12,861 and $18,815, respectively) Total loans held for investment, net of unearned income Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes loans and leases covered under loss sharing agreements. Covered loans, percent Percent of loans and leases receivable covered by loss sharing agreements. Schedule of Covered Loans Held for Investment Net of Unearned Income [Table Text Block] Tabular disclosure of covered loans held for investment, net of unearned income. Non-covered loans, percent Percent before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements. fcbc_LoansAndLeasesReceivableNetOfDeferredIncomeAndNetReportedAmountPercent Total loans held for investment, net of unearned income, percent Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes loans and leases covered under loss sharing agreements. Purchased Credit Impaired Loans [Member] Information pertaining to purchased credit impaired loans. us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsAdditionalDisclosuresAcquisitionCostExpensed Business Combination, Separately Recognized Transactions, Additional Disclosures, Acquisition Cost Expensed Net income Net income Net income Peoples Bank of Virginia [Member] Information pertaining to Peoples Bank of Virginia. Waccamaw Bank [Member] Information pertaining to Waccamaw Bank. us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing Financing Receivable, 90 Days or More Past Due, Still Accruing Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Accretable Yield [Table Text Block] Tabular disclosure of certain loans acquired in transfer not accounted for as debt securities accretable yield. Financing Receivable Credit Quality Indicators [Table Text Block] Other Receivables [Member] Information pertaining to other receivables. Restricted Stock [Member] Current loans Share-based Payment Arrangement, Option [Member] Other changes, net Amount of removals, extensions, and other events in the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality. Past due Total nonaccrual loans Financial Asset, 30 to 59 Days Past Due [Member] Antidilutive Securities [Axis] Financial Asset, 60 to 89 Days Past Due [Member] Antidilutive Securities, Name [Domain] Financial Asset, Equal to or Greater than 90 Days Past Due [Member] Financing Receivable, Past Due [Table Text Block] Financial Asset, Period Past Due [Axis] Financial Asset, Period Past Due [Domain] Financing Receivables [Text Block] Business Combination Disclosure [Text Block] Schedule of Business Acquisitions, by Acquisition [Table Text Block] us-gaap_PaymentsForProceedsFromLoansAndLeases Proceeds from repayments loans, net Non-covered Loans [Member] Information pertaining to non-covered loans. Covered Loans [Member] Information pertaining to covered loans. fcbc_RestructuredLoansReserves Restructured Loans, Reserves Represents the amount of reserves for restructured loans. us-gaap_PaymentsForProceedsFromFederalHomeLoanBankStock Payments for (redemption of) FHLB stock, net us-gaap_RelatedPartyDepositLiabilities Related Party Deposit Liabilities Decrease in other operating activities Investing activities Extinguishment of Debt, Type [Domain] Earnings per common share Earnings Per Share [Text Block] us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty Related Party Transaction, Expenses from Transactions with Related Party Investment in Federal Home Loan Bank (FHLB) and Federal Reserve Bank (FRB) Stock [Member] This item represents the amount shown on an entity's books for investments in Federal Home Loan Bank stock and Federal Reserve Bank stock. Discount range, impaired loans The measurement input for non-covered impaired loans. fcbc_MinimumPrincipalBalanceOfLoansForQuarterlyRatingReview Minimum Principal Balance of Loans for Quarterly Rating Review Minimum amount of principal for loans to be reviewed that are deemed to be impaired. Payments to the FDIC The amount of cash payments received (made) on FDIC indemnification asset. Other Investments [Policy Text Block] Disclosure of accounting policy for all other investments not included in marketable and nonmarketable securities. Extinguishment of Debt [Axis] Discount range, covered OREO The measurement input for covered other real estate owned. Discount range, non-covered OREO The measurement input for non-covered other real estate owned. Related Party Transactions Disclosure [Text Block] Schedule of Related Party Transactions [Table Text Block] Equipment, Computer Hardware and Software [Member] Represents all equipment, computer hardware, and software. us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount Debt Instrument, Unused Borrowing Capacity, Amount Pre-tax compensation expense Impaired Financing Receivables, Summarized Information [Table Text Block] Tabular disclosure of summarized information for impaired financing receivables. Changes in fair value Schedule of Impaired Financing Receivable, Average Recorded Investment and Interest Income Recognized [Table Text Block] Tabular disclosure of impaired financing receivable related to average recorded investment and interest income recognized. Trouble Debt Restructuring Accrual Status [Table Text Block] Tabular disclosure of accrual status related to trouble debt restructuring . Loans individually evaluated for impairment Loans collectively evaluated for impairment Financing Receivable, Collectively Evaluated for Impairment Nonaccrual Recorded investment in financing receivables that have been modified by troubled debt restructurings and are on nonaccrual status as of the balance sheet date. Troubled Debt Restructurings [Member] Information pertaining to trouble debt restructurings. Allowance for loans individually evaluated Allowance for loans collectively evaluated Accrual Recorded investment in financing receivables that have been modified by troubled debt restructurings and are on accrual status as of the balance sheet date. Interest Income Related to Troubled Debt Restructurings [Table Text Block] Tabular disclosure of interest income related to troubled debt restructurings. us-gaap_ComprehensiveIncomeNetOfTax Total comprehensive income fcbc_NumberOfSecuritiesInUnrealizedLossPositionGreaterThanOrEqualToOneYear Number of Securities in Unrealized Loss Position, Greater than or Equal to One Year Number of investment positions that have been in a continuous unrealized loss position for greater than or equal to a year. Financial Asset Acquired and No Credit Deterioration [Member] Credit Loss Status [Axis] Other Real Estate Owned [Table Text Block] Tabular disclosure of other real estate owned. 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