XML 140 R106.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Pension and Other Postretirement Benefits - Fair Values of Pension Plan Assets by Asset Category (Detail) (USD $) In Thousands, unless otherwise specified | Dec. 31, 2014 | Dec. 31, 2013
--- | --- | ---
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category | $ 216,754 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets | $ 198,367 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
Large-Cap Fund [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category | 82,816 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = bdc_LargeCapMember | 75,306 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = bdc_LargeCapMember
Mid-Cap Fund [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category | 15,276 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = bdc_MidCapMember | 13,511 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = bdc_MidCapMember
Small-Cap Fund [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category | 19,952 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = bdc_SmallCapMember | 19,473 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = bdc_SmallCapMember
Government Bond Fund [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category | 29,121 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_USGovernmentAgenciesDebtSecuritiesMember | 25,520 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_USGovernmentAgenciesDebtSecuritiesMember
Corporate Bond Fund [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category | 27,485 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_CorporateDebtSecuritiesMember | 21,679 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_CorporateDebtSecuritiesMember
Fixed Income Fund [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category | 41,975 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_FixedIncomeFundsMember | 42,847 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_FixedIncomeFundsMember
Cash & Equivalents [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category | 129 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_CashAndCashEquivalentsMember | 31 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_CashAndCashEquivalentsMember
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category | 10,362 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member | 31 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Large-Cap Fund [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category | 3,414 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = bdc_LargeCapMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Mid-Cap Fund [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category | 1,448 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = bdc_MidCapMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Small-Cap Fund [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category | 312 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = bdc_SmallCapMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Government Bond Fund [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category | 1,244 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_USGovernmentAgenciesDebtSecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Corporate Bond Fund [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category | 3,815 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_CorporateDebtSecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fixed Income Fund [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category |  |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Cash & Equivalents [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category | 129 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_CashAndCashEquivalentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member | 31 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_CashAndCashEquivalentsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Significant Observable Inputs (Level 2) [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category | 206,392 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member | 198,336 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member
Significant Observable Inputs (Level 2) [Member] | Large-Cap Fund [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category | 79,402 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = bdc_LargeCapMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member | 75,306 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = bdc_LargeCapMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member
Significant Observable Inputs (Level 2) [Member] | Mid-Cap Fund [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category | 13,828 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = bdc_MidCapMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member | 13,511 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = bdc_MidCapMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member
Significant Observable Inputs (Level 2) [Member] | Small-Cap Fund [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category | 19,640 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = bdc_SmallCapMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member | 19,473 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = bdc_SmallCapMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member
Significant Observable Inputs (Level 2) [Member] | Government Bond Fund [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category | 27,877 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_USGovernmentAgenciesDebtSecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member | 25,520 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_USGovernmentAgenciesDebtSecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member
Significant Observable Inputs (Level 2) [Member] | Corporate Bond Fund [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category | 23,670 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_CorporateDebtSecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member | 21,679 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_CorporateDebtSecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member
Significant Observable Inputs (Level 2) [Member] | Fixed Income Fund [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category | 41,975 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_FixedIncomeFundsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member | 42,847 us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_FixedIncomeFundsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member
Significant Observable Inputs (Level 2) [Member] | Cash & Equivalents [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category |  |
Significant Unobservable Inputs (Level 3) [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category |  |
Significant Unobservable Inputs (Level 3) [Member] | Large-Cap Fund [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category |  |
Significant Unobservable Inputs (Level 3) [Member] | Mid-Cap Fund [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category |  |
Significant Unobservable Inputs (Level 3) [Member] | Small-Cap Fund [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category |  |
Significant Unobservable Inputs (Level 3) [Member] | Government Bond Fund [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category |  |
Significant Unobservable Inputs (Level 3) [Member] | Corporate Bond Fund [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category |  |
Significant Unobservable Inputs (Level 3) [Member] | Fixed Income Fund [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category |  |
Significant Unobservable Inputs (Level 3) [Member] | Cash & Equivalents [Member] |  |
Pension And Other Employee Benefit Plans [Line Items] |  |
Fair values of pension plan assets by asset category |  |

X
- Details
Name: | bdc_PensionAndOtherEmployeeBenefitPlansLineItems
Namespace Prefix: | bdc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Assets, 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. + References 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=35743120&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 + Details
Name: | us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=bdc_LargeCapMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=bdc_MidCapMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=bdc_SmallCapMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_CashAndCashEquivalentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_FixedIncomeFundsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_USGovernmentAgenciesDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |