XML 38 R43.htm IDEA: XBRL DOCUMENT v2.4.1.9
LOANS (Details 3) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Non-accrual loans    
Non-accrual loans $ 20,989us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus $ 20,539us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
Business Activity    
Non-accrual loans    
Non-accrual loans 14,636us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansFromBusinessActivitiesMember		 14,778us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansFromBusinessActivitiesMember
Acquired Loans    
Non-accrual loans    
Non-accrual loans 6,353us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansAcquiredFromBusinessCombinationsMember		 5,761us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansAcquiredFromBusinessCombinationsMember
Acquired credit impaired loans    
Non-accrual loans    
Non-accrual loans 1,000us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_AcquiredCreditImpairedLoansMember		 1,200us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_AcquiredCreditImpairedLoansMember
Residential | Mortgages    
Non-accrual loans    
Non-accrual loans 4,153us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancialInstrumentAxis
= us-gaap_MortgagesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		 3,908us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancialInstrumentAxis
= us-gaap_MortgagesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember
Residential | Mortgages | Business Activity    
Non-accrual loans    
Non-accrual loans 2,367us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansFromBusinessActivitiesMember
/ us-gaap_FinancialInstrumentAxis
= us-gaap_MortgagesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		 2,526us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansFromBusinessActivitiesMember
/ us-gaap_FinancialInstrumentAxis
= us-gaap_MortgagesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember
Residential | Mortgages | Acquired Loans    
Non-accrual loans    
Non-accrual loans 1,786us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansAcquiredFromBusinessCombinationsMember
/ us-gaap_FinancialInstrumentAxis
= us-gaap_MortgagesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember		 1,382us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansAcquiredFromBusinessCombinationsMember
/ us-gaap_FinancialInstrumentAxis
= us-gaap_MortgagesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember
Residential | Mortgages | 1-4 family    
Non-accrual loans    
Non-accrual loans 4,153us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancialInstrumentAxis
= us-gaap_MortgagesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= bhlb_Family1To4Member		 3,908us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancialInstrumentAxis
= us-gaap_MortgagesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= bhlb_Family1To4Member
Residential | Mortgages | 1-4 family | Business Activity    
Non-accrual loans    
Non-accrual loans 2,367us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansFromBusinessActivitiesMember
/ us-gaap_FinancialInstrumentAxis
= us-gaap_MortgagesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= bhlb_Family1To4Member		 2,526us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansFromBusinessActivitiesMember
/ us-gaap_FinancialInstrumentAxis
= us-gaap_MortgagesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= bhlb_Family1To4Member
Residential | Mortgages | 1-4 family | Acquired Loans    
Non-accrual loans    
Non-accrual loans 1,786us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansAcquiredFromBusinessCombinationsMember
/ us-gaap_FinancialInstrumentAxis
= us-gaap_MortgagesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= bhlb_Family1To4Member		 1,382us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansAcquiredFromBusinessCombinationsMember
/ us-gaap_FinancialInstrumentAxis
= us-gaap_MortgagesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ResidentialPortfolioSegmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= bhlb_Family1To4Member
Commercial real estate    
Non-accrual loans    
Non-accrual loans 12,510us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 11,756us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
Commercial real estate | Business Activity    
Non-accrual loans    
Non-accrual loans 10,100us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansFromBusinessActivitiesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 9,940us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansFromBusinessActivitiesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
Commercial real estate | Acquired Loans    
Non-accrual loans    
Non-accrual loans 2,410us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansAcquiredFromBusinessCombinationsMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 1,816us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansAcquiredFromBusinessCombinationsMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
Commercial real estate | Construction    
Non-accrual loans    
Non-accrual loans 758us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= us-gaap_ConstructionLoansMember		 720us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= us-gaap_ConstructionLoansMember
Commercial real estate | Construction | Business Activity    
Non-accrual loans    
Non-accrual loans 758us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansFromBusinessActivitiesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= us-gaap_ConstructionLoansMember		 720us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansFromBusinessActivitiesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= us-gaap_ConstructionLoansMember
Commercial real estate | Single and multi-family    
Non-accrual loans    
Non-accrual loans 877us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= bhlb_SingleAndMultiFamilyMember		 599us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= bhlb_SingleAndMultiFamilyMember
Commercial real estate | Single and multi-family | Business Activity    
Non-accrual loans    
Non-accrual loans 406us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansFromBusinessActivitiesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= bhlb_SingleAndMultiFamilyMember		 458us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansFromBusinessActivitiesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= bhlb_SingleAndMultiFamilyMember
Commercial real estate | Single and multi-family | Acquired Loans    
Non-accrual loans    
Non-accrual loans 471us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansAcquiredFromBusinessCombinationsMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= bhlb_SingleAndMultiFamilyMember		 141us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansAcquiredFromBusinessCombinationsMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= bhlb_SingleAndMultiFamilyMember
Commercial real estate | Other commercial real estate    
Non-accrual loans    
Non-accrual loans 10,875us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= us-gaap_CommercialRealEstateMember		 10,437us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= us-gaap_CommercialRealEstateMember
Commercial real estate | Other commercial real estate | Business Activity    
Non-accrual loans    
Non-accrual loans 8,936us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansFromBusinessActivitiesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= us-gaap_CommercialRealEstateMember		 8,762us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansFromBusinessActivitiesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= us-gaap_CommercialRealEstateMember
Commercial real estate | Other commercial real estate | Acquired Loans    
Non-accrual loans    
Non-accrual loans 1,939us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansAcquiredFromBusinessCombinationsMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= us-gaap_CommercialRealEstateMember		 1,675us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansAcquiredFromBusinessCombinationsMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= us-gaap_CommercialRealEstateMember
Commercial real estate | Business loans    
Non-accrual loans    
Non-accrual loans 1,294us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancialInstrumentAxis
= us-gaap_CommercialLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 1,661us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancialInstrumentAxis
= us-gaap_CommercialLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
Commercial real estate | Business loans | Business Activity    
Non-accrual loans    
Non-accrual loans 725us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansFromBusinessActivitiesMember
/ us-gaap_FinancialInstrumentAxis
= us-gaap_CommercialLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 850us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansFromBusinessActivitiesMember
/ us-gaap_FinancialInstrumentAxis
= us-gaap_CommercialLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
Commercial real estate | Business loans | Acquired Loans    
Non-accrual loans    
Non-accrual loans 569us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansAcquiredFromBusinessCombinationsMember
/ us-gaap_FinancialInstrumentAxis
= us-gaap_CommercialLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 811us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansAcquiredFromBusinessCombinationsMember
/ us-gaap_FinancialInstrumentAxis
= us-gaap_CommercialLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
Commercial real estate | Business loans | Other commercial and industrial loans    
Non-accrual loans    
Non-accrual loans 1,294us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= bhlb_OtherCommercialBusinessLoanMember
/ us-gaap_FinancialInstrumentAxis
= us-gaap_CommercialLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 1,661us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= bhlb_OtherCommercialBusinessLoanMember
/ us-gaap_FinancialInstrumentAxis
= us-gaap_CommercialLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
Commercial real estate | Business loans | Other commercial and industrial loans | Business Activity    
Non-accrual loans    
Non-accrual loans 725us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= bhlb_OtherCommercialBusinessLoanMember
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansFromBusinessActivitiesMember
/ us-gaap_FinancialInstrumentAxis
= us-gaap_CommercialLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 850us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= bhlb_OtherCommercialBusinessLoanMember
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansFromBusinessActivitiesMember
/ us-gaap_FinancialInstrumentAxis
= us-gaap_CommercialLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
Commercial real estate | Business loans | Other commercial and industrial loans | Acquired Loans    
Non-accrual loans    
Non-accrual loans 569us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= bhlb_OtherCommercialBusinessLoanMember
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansAcquiredFromBusinessCombinationsMember
/ us-gaap_FinancialInstrumentAxis
= us-gaap_CommercialLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember		 811us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= bhlb_OtherCommercialBusinessLoanMember
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansAcquiredFromBusinessCombinationsMember
/ us-gaap_FinancialInstrumentAxis
= us-gaap_CommercialLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialRealEstatePortfolioSegmentMember
Consumer    
Non-accrual loans    
Non-accrual loans 3,032us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 3,214us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Consumer | Business Activity    
Non-accrual loans    
Non-accrual loans 1,444us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansFromBusinessActivitiesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 1,462us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansFromBusinessActivitiesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Consumer | Acquired Loans    
Non-accrual loans    
Non-accrual loans 1,588us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansAcquiredFromBusinessCombinationsMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 1,752us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansAcquiredFromBusinessCombinationsMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Consumer | Home equity    
Non-accrual loans    
Non-accrual loans 2,068us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 1,740us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Consumer | Home equity | Business Activity    
Non-accrual loans    
Non-accrual loans 1,192us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansFromBusinessActivitiesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 1,157us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansFromBusinessActivitiesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Consumer | Home equity | Acquired Loans    
Non-accrual loans    
Non-accrual loans 876us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansAcquiredFromBusinessCombinationsMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 583us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansAcquiredFromBusinessCombinationsMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Consumer | Auto and other    
Non-accrual loans    
Non-accrual loans 964us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= bhlb_AutoAndOtherReceivableMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 1,474us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= bhlb_AutoAndOtherReceivableMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Consumer | Auto and other | Business Activity    
Non-accrual loans    
Non-accrual loans 252us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= bhlb_AutoAndOtherReceivableMember
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansFromBusinessActivitiesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 305us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= bhlb_AutoAndOtherReceivableMember
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansFromBusinessActivitiesMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember
Consumer | Auto and other | Acquired Loans    
Non-accrual loans    
Non-accrual loans $ 712us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= bhlb_AutoAndOtherReceivableMember
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansAcquiredFromBusinessCombinationsMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 $ 1,169us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= bhlb_AutoAndOtherReceivableMember
/ bhlb_AccountsNotesLoansAndFinancingReceivableBySourceAxis
= bhlb_LoansAcquiredFromBusinessCombinationsMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember