2.4.0.800105 - Statement - Consolidated Balance Sheets (Parenthetical)truefalseIn Thousands, except Share data, unless otherwise specifiedfalse1false USDfalsefalse$As_Of_6_30_2013http://www.sec.gov/CIK0000743367instant2013-06-30T00:00:000001-01-01T00:00:00Unit16Standardhttp://www.xbrl.org/2003/instancesharesxbrli0Unit17Dividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0Unit1Standardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$2false USDfalsefalse$As_Of_12_31_2012http://www.sec.gov/CIK0000743367instant2012-12-31T00:00:000001-01-01T00:00:00Unit16Standardhttp://www.xbrl.org/2003/instancesharesxbrli0Unit17Dividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0Unit1Standardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$1true 1us-gaap_StatementOfFinancialPositionAbstractus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Consolidated Balance Sheets [Abstract]2false 2us-gaap_AvailableForSaleSecuritiesAmortizedCostus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalsenetLabel1truefalsefalse421977000421977USD$falsetruefalse2truefalsefalse405769000405769USD$falsetruefalsexbrli:monetaryItemTypemonetaryThis item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.2) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 7 -Footnote 2 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 19 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false2Securities available for sale, amortized cost3false 2us-gaap_CommonStockParOrStatedValuePerShareus-gaap_truenainstantfalsefalsefalsefalsefalsefalsefalsefalse1truefalsefalse22USD$falsetruefalse2truefalsefalse22USD$falsetruefalsenum:perShareItemTypedecimalFace amount or stated value of common stock per share; generally not indicative of the fair market value per share.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 4 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.29) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 30 -Article 5 false3Capital stock, par value4false 2us-gaap_CommonStockSharesAuthorizedus-gaap_truenainstantfalsefalsefalsefalsefalsefalsefalsefalse1truefalsefalse1000000010000000falsefalsefalse2truefalsefalse1000000010000000falsefalsefalsexbrli:sharesItemTypesharesThe maximum number of common shares permitted to be issued by an entity's charter and bylaws.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.29) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 30 -Article 5 false1Capital stock, shares authorized5false 2us-gaap_CommonStockSharesIssuedus-gaap_truenainstantfalsefalsefalsefalsefalsefalsefalsefalse1truefalsefalse45256354525635falsefalsefalse2truefalsefalse45256354525635falsefalsefalsexbrli:sharesItemTypesharesTotal number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.29) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 30 -Article 5 false1Capital stock, shares issued6false 2bhb_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostRecognizedAndUnamortizedNetActuarialLossTaxbhb_falsecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse-251000-251falsefalsefalse2truefalsefalse-207000-207falsefalsefalsexbrli:monetaryItemTypemonetaryOther Comprehensive Income Defined Benefit Plan Net Prior Service Cost Recognized And Unamortized Net Actuarial Loss TaxNo definition available.false2Prior service cost and unamortized net actuarial losses on employee benefit plans, tax7false 2bhb_OtherComprehensiveIncomeNetUnrealizedAppreciationOnSecuritiesAvailableForSaleTaxbhb_falsedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse-2193000-2193falsefalsefalse2truefalsefalse40990004099falsefalsefalsexbrli:monetaryItemTypemonetaryOther Comprehensive Income Net Unrealized Appreciation On Securities Available For Sale TaxNo definition available.false2Net unrealized appreciation on securities available for sale, tax8false 2bhb_OtherComprehensiveIncomeOtherThanTemporaryImpairmentLossesAttributableToNonCreditLossTaxbhb_falsedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse242000242USD$falsetruefalse2truefalsefalse7400074USD$falsetruefalsexbrli:monetaryItemTypemonetaryOther Comprehensive Income Other Than Temporary Impairment Losses Attributable To Non Credit Loss TaxNo definition available.false2Portion of OTTI attributable to non-credit losses, tax9false 2us-gaap_TreasuryStockSharesus-gaap_truenainstantfalsefalsefalsefalsefalsefalsefalsefalselabel1truefalsefalse594498594498falsefalsefalse2truefalsefalse605591605591falsefalsefalsexbrli:sharesItemTypesharesNumber of common and preferred shares that were previously issued and that were repurchased by the issuing entity and held in treasury on the financial statement date. This stock has no voting rights and receives no dividends.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.28,29) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 29, 30 -Article 5 false1Treasury stock, sharesfalseConsolidated Balance Sheets (Parenthetical) (USD $)ThousandsNoRoundingNoRoundingUnKnowntruefalsefalseSheethttp://www.bhbt.com/2011-03-31/role/StatementConsolidatedBalanceSheetsParenthetical29