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SUBSEQUENT EVENTS (Details) (USD $)
Share data in Millions, unless otherwise specified
0 Months Ended
Apr. 17, 2015
Mar. 31, 2015
Dec. 31, 2014
SUBSEQUENT EVENTS      
Total Assets   $ 6,571,239,000us-gaap_Assets $ 6,502,031,000us-gaap_Assets
Deposits   4,719,683,000us-gaap_Deposits 4,654,679,000us-gaap_Deposits
Hampden      
SUBSEQUENT EVENTS      
Merger and acquisition expenses   3,300,000us-gaap_BusinessAcquisitionCostOfAcquiredEntityTransactionCosts
/ us-gaap_BusinessAcquisitionAxis
= bhlb_HampdenBancorpIncMember
 
Hampden | Subsequent event      
SUBSEQUENT EVENTS      
Number of banking offices operated 10us-gaap_NumberOfStores
/ us-gaap_BusinessAcquisitionAxis
= bhlb_HampdenBancorpIncMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
   
Number of shares received by shareholders 4.2us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued
/ us-gaap_BusinessAcquisitionAxis
= bhlb_HampdenBancorpIncMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
   
Hampden      
SUBSEQUENT EVENTS      
Total Assets 687,800,000us-gaap_Assets
/ dei_LegalEntityAxis
= bhlb_HampdenBancorpIncMember
   
Loans outstanding 501,000,000us-gaap_LongTermDebtNoncurrent
/ dei_LegalEntityAxis
= bhlb_HampdenBancorpIncMember
   
Deposits 482,100,000us-gaap_Deposits
/ dei_LegalEntityAxis
= bhlb_HampdenBancorpIncMember