XML 20 R42.htm IDEA: XBRL DOCUMENT v2.4.1.9
INCOME TAXES (Details) (USD $)
3 Months Ended 12 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Dec. 31, 2014
Income Taxes [Line Items]      
Income taxes payable $ 37,000us-gaap_LiabilityForUncertainTaxPositionsCurrent   $ 203,000us-gaap_LiabilityForUncertainTaxPositionsCurrent
Liability for uncertain tax positions 40,781,000us-gaap_LiabilityForUncertainTaxPositionsNoncurrent   39,767,000us-gaap_LiabilityForUncertainTaxPositionsNoncurrent
Unrecognized tax benefit 40,818,000us-gaap_UnrecognizedTaxBenefits   39,970,000us-gaap_UnrecognizedTaxBenefits
Liability for uncertain tax position that would impact effective tax rate 2,900,000us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate   2,800,000us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate
Interest and penalties uncertain tax positions recognized 900,000us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense 0us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense  
Accrued interest and penalties uncertain tax positions 2,500,000us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued   1,600,000us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued
Deferred tax liability, net 7,500,000us-gaap_DeferredTaxAssetsLiabilitiesNet    
Power Solutions [Member]      
Income Taxes [Line Items]      
Interest and penalties uncertain tax positions recognized 2,100,000us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense
/ us-gaap_BusinessAcquisitionAxis
= belfb_PowerSolutionsMember
   
Interest and penalties uncertain tax positions recognized until various tax matters are resolved 2,500,000us-gaap_TaxAdjustmentsSettlementsAndUnusualProvisions
/ us-gaap_BusinessAcquisitionAxis
= belfb_PowerSolutionsMember
   
Deferred tax assets 7,100,000us-gaap_DeferredTaxAssetsGross
/ us-gaap_BusinessAcquisitionAxis
= belfb_PowerSolutionsMember
   
Deferred tax liability 3,100,000us-gaap_DeferredTaxLiabilities
/ us-gaap_BusinessAcquisitionAxis
= belfb_PowerSolutionsMember
   
Connectivity Solutions [Member]      
Income Taxes [Line Items]      
Deferred tax assets 1,200,000us-gaap_DeferredTaxAssetsGross
/ us-gaap_BusinessAcquisitionAxis
= belfb_EmersonNetworkPowerConnectivitySolutionsMember
   
Deferred tax liability 16,400,000us-gaap_DeferredTaxLiabilities
/ us-gaap_BusinessAcquisitionAxis
= belfb_EmersonNetworkPowerConnectivitySolutionsMember
   
Asia [Member] | Power Solutions [Member]      
Income Taxes [Line Items]      
Additions relating to acquisitions     35,800,000belfb_AdditionsRelatingToAcquisitions
/ us-gaap_BusinessAcquisitionAxis
= belfb_PowerSolutionsMember
/ us-gaap_StatementGeographicalAxis
= us-gaap_AsiaMember
Foreign jurisdictions [Member] | Asia [Member] | Power Solutions [Member]      
Income Taxes [Line Items]      
Additions relating to acquisitions     $ 12,000,000belfb_AdditionsRelatingToAcquisitions
/ us-gaap_BusinessAcquisitionAxis
= belfb_PowerSolutionsMember
/ us-gaap_IncomeTaxAuthorityAxis
= us-gaap_ForeignCountryMember
/ us-gaap_StatementGeographicalAxis
= us-gaap_AsiaMember