<?xml version="1.0" encoding="utf-8"?>
<FilingSummary xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <Version>2.4.0.6</Version>
  <ProcessingTime />
  <ReportFormat>Html</ReportFormat>
  <ContextCount>333</ContextCount>
  <ElementCount>281</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>62</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>4</UnitCount>
  <MyReports>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>00090 - Document - Document And Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DocumentDocumentAndEntityInformation</Role>
      <ShortName>Document And Entity Information</ShortName>
    </Report>
    <Report>
      <IsDefault>true</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>00100 - Statement - Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/StatementConsolidatedBalanceSheets</Role>
      <ShortName>Consolidated Balance Sheets</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>00105 - Statement - Consolidated Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/StatementConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>Consolidated Balance Sheets (Parenthetical)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>00200 - Statement - Consolidated Statements Of Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/StatementConsolidatedStatementsOfIncome</Role>
      <ShortName>Consolidated Statements Of Income</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>00300 - Statement - Consolidated Statements Of Comprehensive Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/StatementConsolidatedStatementsOfComprehensiveIncome</Role>
      <ShortName>Consolidated Statements Of Comprehensive Income</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>00305 - Statement - Consolidated Statements Of Comprehensive Income (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/StatementConsolidatedStatementsOfComprehensiveIncomeParenthetical</Role>
      <ShortName>Consolidated Statements Of Comprehensive Income (Parenthetical)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>00400 - Statement - Consolidated Statements Of Changes In Shareholders' Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/StatementConsolidatedStatementsOfChangesInShareholdersEquity</Role>
      <ShortName>Consolidated Statements Of Changes In Shareholders' Equity</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>00405 - Statement - Consolidated Statements Of Changes In Shareholders' Equity (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/StatementConsolidatedStatementsOfChangesInShareholdersEquityParenthetical</Role>
      <ShortName>Consolidated Statements Of Changes In Shareholders' Equity (Parenthetical)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>00500 - Statement - Consolidated Statements Of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/StatementConsolidatedStatementsOfCashFlows</Role>
      <ShortName>Consolidated Statements Of Cash Flows</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>10101 - Disclosure - Basis Of Presentation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureBasisOfPresentation</Role>
      <ShortName>Basis Of Presentation</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>10201 - Disclosure - Management's Use Of Estimates</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureManagementSUseOfEstimates</Role>
      <ShortName>Management's Use Of Estimates</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>10301 - Disclosure - Earnings Per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureEarningsPerShare</Role>
      <ShortName>Earnings Per Share</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>10401 - Disclosure - Securities Available For Sale</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureSecuritiesAvailableForSale</Role>
      <ShortName>Securities Available For Sale</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>10501 - Disclosure - Loans And Allowance For Loan Losses</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureLoansAndAllowanceForLoanLosses</Role>
      <ShortName>Loans And Allowance For Loan Losses</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>10601 - Disclosure - Retirement Benefit Plans</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureRetirementBenefitPlans</Role>
      <ShortName>Retirement Benefit Plans</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>10701 - Disclosure - Commitments And Contingent Liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureCommitmentsAndContingentLiabilities</Role>
      <ShortName>Commitments And Contingent Liabilities</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>10801 - Disclosure - Fair Value Measurements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureFairValueMeasurements</Role>
      <ShortName>Fair Value Measurements</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>10901 - Disclosure - Fair Value Of Financial Instruments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureFairValueOfFinancialInstruments</Role>
      <ShortName>Fair Value Of Financial Instruments</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>20202 - Disclosure - Management's Use Of Estimates (Policy)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureManagementSUseOfEstimatesPolicy</Role>
      <ShortName>Management's Use Of Estimates (Policy)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>30303 - Disclosure - Earnings Per Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureEarningsPerShareTables</Role>
      <ShortName>Earnings Per Share (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>30403 - Disclosure - Securities Available For Sale (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureSecuritiesAvailableForSaleTables</Role>
      <ShortName>Securities Available For Sale (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>30503 - Disclosure - Loans And Allowance For Loan Losses (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureLoansAndAllowanceForLoanLossesTables</Role>
      <ShortName>Loans And Allowance For Loan Losses (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>30603 - Disclosure - Retirement Benefit Plans (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureRetirementBenefitPlansTables</Role>
      <ShortName>Retirement Benefit Plans (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>30703 - Disclosure - Commitments And Contingent Liabilities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureCommitmentsAndContingentLiabilitiesTables</Role>
      <ShortName>Commitments And Contingent Liabilities (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>30803 - Disclosure - Fair Value Measurements (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureFairValueMeasurementsTables</Role>
      <ShortName>Fair Value Measurements (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>30903 - Disclosure - Fair Value Of Financial Instruments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureFairValueOfFinancialInstrumentsTables</Role>
      <ShortName>Fair Value Of Financial Instruments (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>40301 - Disclosure - Earnings Per Share (Reconciliation Of Basic And Diluted Earnings Per Share) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureEarningsPerShareReconciliationOfBasicAndDilutedEarningsPerShareDetails</Role>
      <ShortName>Earnings Per Share (Reconciliation Of Basic And Diluted Earnings Per Share) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>40401 - Disclosure - Securities Available For Sale (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureSecuritiesAvailableForSaleNarrativeDetails</Role>
      <ShortName>Securities Available For Sale (Narrative) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>40402 - Disclosure - Securities Available For Sale (Summary Of Securities Available For Sale) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureSecuritiesAvailableForSaleSummaryOfSecuritiesAvailableForSaleDetails</Role>
      <ShortName>Securities Available For Sale (Summary Of Securities Available For Sale) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>40403 - Disclosure - Securities Available For Sale (Schedule Of Maturities Distribution Of The Amortized Cost And Estimated Fair Value Of Securities Available For Sale) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureSecuritiesAvailableForSaleScheduleOfMaturitiesDistributionOfAmortizedCostAndEstimatedFairValueOfSecuritiesAvailableForSaleDetails</Role>
      <ShortName>Securities Available For Sale (Schedule Of Maturities Distribution Of The Amortized Cost And Estimated Fair Value Of Securities Available For Sale) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>40404 - Disclosure - Securities Available For Sale (Schedule Of OTTI Related To Historical Estimated Credit Losses On Debt Securities And Changes In Estimated Credit Losses Recognized In Pre-Tax Earnings) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureSecuritiesAvailableForSaleScheduleOfOttiRelatedToHistoricalEstimatedCreditLossesOnDebtSecuritiesAndChangesInEstimatedCreditLossesRecognizedInPreTaxEarningsDetails</Role>
      <ShortName>Securities Available For Sale (Schedule Of OTTI Related To Historical Estimated Credit Losses On Debt Securities And Changes In Estimated Credit Losses Recognized In Pre-Tax Earnings) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>40405 - Disclosure - Securities Available For Sale (Schedule Of Fair Value Of Securities With Continuous Unrealized Losses) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureSecuritiesAvailableForSaleScheduleOfFairValueOfSecuritiesWithContinuousUnrealizedLossesDetails</Role>
      <ShortName>Securities Available For Sale (Schedule Of Fair Value Of Securities With Continuous Unrealized Losses) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>40406 - Disclosure - Securities Available For Sale (Schedule Of Realized Gains And Losses And Other-Than-Temporary Impairment Losses On Securities) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureSecuritiesAvailableForSaleScheduleOfRealizedGainsAndLossesAndOtherThanTemporaryImpairmentLossesOnSecuritiesDetails</Role>
      <ShortName>Securities Available For Sale (Schedule Of Realized Gains And Losses And Other-Than-Temporary Impairment Losses On Securities) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>40501 - Disclosure - Loans And Allowance For Loan Losses (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureLoansAndAllowanceForLoanLossesNarrativeDetails</Role>
      <ShortName>Loans And Allowance For Loan Losses (Narrative) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>40502 - Disclosure - Loans And Allowance For Loan Losses (Summary Of Composition Of Loan Portfolio) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureLoansAndAllowanceForLoanLossesSummaryOfCompositionOfLoanPortfolioDetails</Role>
      <ShortName>Loans And Allowance For Loan Losses (Summary Of Composition Of Loan Portfolio) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>40503 - Disclosure - Loans And Allowance For Loan Losses (Summary Of Non Performing Loans) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureLoansAndAllowanceForLoanLossesSummaryOfNonPerformingLoansDetails</Role>
      <ShortName>Loans And Allowance For Loan Losses (Summary Of Non Performing Loans) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>40504 - Disclosure - Loans And Allowance For Loan Losses (Summary Of Troubled Debt Restructures) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureLoansAndAllowanceForLoanLossesSummaryOfTroubledDebtRestructuresDetails</Role>
      <ShortName>Loans And Allowance For Loan Losses (Summary Of Troubled Debt Restructures) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>40505 - Disclosure - Loans And Allowance For Loan Losses (Schedule Of Past Due Loans) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureLoansAndAllowanceForLoanLossesScheduleOfPastDueLoansDetails</Role>
      <ShortName>Loans And Allowance For Loan Losses (Schedule Of Past Due Loans) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>40506 - Disclosure - Loans And Allowance For Loan Losses (Schedule Of Impaired Loans) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureLoansAndAllowanceForLoanLossesScheduleOfImpairedLoansDetails</Role>
      <ShortName>Loans And Allowance For Loan Losses (Schedule Of Impaired Loans) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>40507 - Disclosure - Loans And Allowance For Loan Losses (Schedule Of Loans With Credit Quality Indicators) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureLoansAndAllowanceForLoanLossesScheduleOfLoansWithCreditQualityIndicatorsDetails</Role>
      <ShortName>Loans And Allowance For Loan Losses (Schedule Of Loans With Credit Quality Indicators) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>40509 - Disclosure - Loans And Allowance For Loan Losses (Schedule Of Allowance For Loan Losses By Portfolio Segment) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureLoansAndAllowanceForLoanLossesScheduleOfAllowanceForLoanLossesByPortfolioSegmentDetails</Role>
      <ShortName>Loans And Allowance For Loan Losses (Schedule Of Allowance For Loan Losses By Portfolio Segment) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>40601 - Disclosure - Retirement Benefit Plans (Summary Of Net Periodic Benefit Costs) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureRetirementBenefitPlansSummaryOfNetPeriodicBenefitCostsDetails</Role>
      <ShortName>Retirement Benefit Plans (Summary Of Net Periodic Benefit Costs) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>40701 - Disclosure - Commitments And Contingent Liabilities (Schedule Of Contractual Amounts Of Commitments And Contingent Liabilities) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureCommitmentsAndContingentLiabilitiesScheduleOfContractualAmountsOfCommitmentsAndContingentLiabilitiesDetails</Role>
      <ShortName>Commitments And Contingent Liabilities (Schedule Of Contractual Amounts Of Commitments And Contingent Liabilities) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>40801 - Disclosure - Fair Value Measurements (Financial Assets And Financial Liabilities Measured At Fair Value On A Recurring Basis) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureFairValueMeasurementsFinancialAssetsAndFinancialLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails</Role>
      <ShortName>Fair Value Measurements (Financial Assets And Financial Liabilities Measured At Fair Value On A Recurring Basis) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>40802 - Disclosure - Fair Value Measurements (Financial Assets And Financial Liabilities Measured At Fair Value On A Non-Recurring Basis) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureFairValueMeasurementsFinancialAssetsAndFinancialLiabilitiesMeasuredAtFairValueOnNonRecurringBasisDetails</Role>
      <ShortName>Fair Value Measurements (Financial Assets And Financial Liabilities Measured At Fair Value On A Non-Recurring Basis) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>40901 - Disclosure - Fair Value Of Financial Instruments (Summary Of The Carrying Values And Estimated Fair Values Of Financial Instruments) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.bhbt.com/2011-03-31/role/DisclosureFairValueOfFinancialInstrumentsSummaryOfCarryingValuesAndEstimatedFairValuesOfFinancialInstrumentsDetails</Role>
      <ShortName>Fair Value Of Financial Instruments (Summary Of The Carrying Values And Estimated Fair Values Of Financial Instruments) (Details)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <Logs>
    <Log type="Info">Process Flow-Through: 00100 - Statement - Consolidated Balance Sheets</Log>
    <Log type="Info">	Process Flow-Through: Removing column 'Jun. 30, 2011'</Log>
    <Log type="Info">	Process Flow-Through: Removing column 'Dec. 31, 2010'</Log>
    <Log type="Info">Process Flow-Through: 00105 - Statement - Consolidated Balance Sheets (Parenthetical)</Log>
    <Log type="Info">Process Flow-Through: 00200 - Statement - Consolidated Statements Of Income</Log>
    <Log type="Info">Process Flow-Through: 00300 - Statement - Consolidated Statements Of Comprehensive Income</Log>
    <Log type="Info">Process Flow-Through: 00305 - Statement - Consolidated Statements Of Comprehensive Income (Parenthetical)</Log>
    <Log type="Info">Process Flow-Through: 00405 - Statement - Consolidated Statements Of Changes In Shareholders' Equity (Parenthetical)</Log>
    <Log type="Info">Process Flow-Through: 00500 - Statement - Consolidated Statements Of Cash Flows</Log>
  </Logs>
  <InputFiles>
    <File>bhb-20120630.xml</File>
    <File>bhb-20120630.xsd</File>
    <File>bhb-20120630_cal.xml</File>
    <File>bhb-20120630_def.xml</File>
    <File>bhb-20120630_lab.xml</File>
    <File>bhb-20120630_pre.xml</File>
  </InputFiles>
  <SupplementalFiles />
  <BaseTaxonomies />
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
