2.4.0.822456407 - Disclosure - Retirement and Benefit Plans Level 4 Changes in Fair Value of Level 3 Assets Rollforward (Details)truefalseIn Thousands, unless otherwise specifiedfalse1false USDfalsefalse$I2012Q4http://www.sec.gov/CIK0001328581instant2012-12-31T00:00:000001-01-01T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$2false USDfalsefalse$I2011Q4http://www.sec.gov/CIK0001328581instant2011-12-31T00:00:000001-01-01T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$3false USDfalsefalse$I2010Q4http://www.sec.gov/CIK0001328581instant2010-12-31T00:00:000001-01-01T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$4false USDtruefalse$I2012Q4_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_us-gaap_RealEstateFundsMemberhttp://www.sec.gov/CIK0001328581instant2012-12-31T00:00:000001-01-01T00:00:00falsefalseReal Estate Funds [Member]us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_RealEstateFundsMemberus-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$5false USDtruefalse$I2011Q4_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_us-gaap_RealEstateFundsMemberhttp://www.sec.gov/CIK0001328581instant2011-12-31T00:00:000001-01-01T00:00:00falsefalseReal Estate Funds [Member]us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_RealEstateFundsMemberus-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$6false USDtruefalse$D2012Q4YTD_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_us-gaap_RealEstateFundsMember_us-gaap_FairValueByFairValueHierarchyLevelAxis_us-gaap_FairValueInputsLevel3Memberhttp://www.sec.gov/CIK0001328581duration2012-01-01T00:00:002012-12-31T00:00:00falsefalseReal Estate Funds [Member]us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_RealEstateFundsMemberus-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxisexplicitMemberfalsefalseFair Value, Inputs, Level 3 [Member]us-gaap_FairValueByFairValueHierarchyLevelAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_FairValueInputsLevel3Memberus-gaap_FairValueByFairValueHierarchyLevelAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$7false USDtruefalse$D2011Q4YTD_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_us-gaap_RealEstateFundsMember_us-gaap_FairValueByFairValueHierarchyLevelAxis_us-gaap_FairValueInputsLevel3Memberhttp://www.sec.gov/CIK0001328581duration2011-01-01T00:00:002011-12-31T00:00:00falsefalseReal Estate Funds [Member]us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_RealEstateFundsMemberus-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxisexplicitMemberfalsefalseFair Value, Inputs, Level 3 [Member]us-gaap_FairValueByFairValueHierarchyLevelAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_FairValueInputsLevel3Memberus-gaap_FairValueByFairValueHierarchyLevelAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$1true 4us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForwardus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse7falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Level 3 Fair Value Rollforward [Roll Forward]2false 5us-gaap_DefinedBenefitPlanFairValueOfPlanAssetsus-gaap_truedebitinstantfalsefalsefalsefalsefalsetruefalsefalseperiodStartLabel1truefalsefalse312224000312224USD$falsetruefalse2truefalsefalse282195000282195USD$falsetruefalse3truefalsefalse281972000281972USD$falsetruefalse4truefalsefalse1431000014310[1]USD$falsetruefalse5truefalsefalse1300000013000[1]USD$falsetruefalse6truefalsefalse1300000013000[1]USD$falsetruefalse7truefalsefalse00USD$falsetruefalsexbrli:monetaryItemTypemonetaryAssets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 30 -Section 35 -Paragraph 50 -URI http://asc.fasb.org/extlink&oid=29635418&loc=d3e12355-114930 false2Fair value of plan assets at beginning of year3false 5us-gaap_DefinedBenefitPlanPurchasesSalesAndSettlementsus-gaap_truedebitdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6truefalsefalse00falsefalsefalse7truefalsefalse1300000013000falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of increase (decrease) in plan assets from purchases, sales and settlement of plan obligations.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(02)(B) -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 5 -Subparagraph (c)(iv)(02)(B) -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e2446-114920 false2Purchases4false 5us-gaap_DefinedBenefitPlanActualReturnOnPlanAssetsStillHeldus-gaap_truedebitdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6truefalsefalse13100001310falsefalsefalse7truefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryActual return on plan assets, separately identifying the amount related to assets still held at the reporting date.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(02)(A) -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 5 -Subparagraph (c)(iv)(02)(A) -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e2446-114920 false2Unrealized gain5false 5us-gaap_DefinedBenefitPlanFairValueOfPlanAssetsus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsetruefalseperiodEndLabel1truefalsefalse312224000312224USD$falsetruefalse2truefalsefalse282195000282195USD$falsetruefalse3truefalsefalse281972000281972USD$falsetruefalse4truefalsefalse1431000014310[1]USD$falsetruefalse5truefalsefalse1300000013000[1]USD$falsetruefalse6truefalsefalse1431000014310[1]USD$falsetruefalse7truefalsefalse1300000013000[1]USD$falsetruefalsexbrli:monetaryItemTypemonetaryAssets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 30 -Section 35 -Paragraph 50 -URI http://asc.fasb.org/extlink&oid=29635418&loc=d3e12355-114930 false2Fair value of plan assets at end of year1Invested in the Russell Real Estate Equity Fund. Real estate investments include those in limited partnerships that invest in various domestic commercial and residential real estate projects. The fair values of real estate assets are typically determined by using income and/or cost approaches or a comparable sales approach, taking into consideration discount and capitalization rates, financial conditions, local market conditions, and the status of the capital markets, and they are thus classified within Level 3. Notwithstanding the above, the variety of valuation bases adopted and quality of management data of the underlying assets means that there are inherent difficulties in determining the value of the investments. Amounts realized on the sale of these investments may differ from the calculated values. We have the ability to redeem the real estate investments with a 110-calendar-day written notice prior to a quarterly trade date.falseRetirement and Benefit Plans Level 4 Changes in Fair Value of Level 3 Assets Rollforward (Details) (USD $)ThousandsUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.bc.com/role/RetirementAndBenefitPlansLevel4ChangesInFairValueOfLevel3AssetsRollforwardDetails75