OTHER ASSETS (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
OTHER ASSETS
Capitalized mortgage servicing rights	$ 3,757us-gaap_ServicingAssetAtAmortizedValue	$ 4,112us-gaap_ServicingAssetAtAmortizedValue	$ 3,198us-gaap_ServicingAssetAtAmortizedValue
Interest Receivable	17,274us-gaap_InterestReceivable	15,070us-gaap_InterestReceivable
Investment in tax credits	9,045bhlb_InvestmentInTaxCredit	5,771bhlb_InvestmentInTaxCredit
Prepaid FDIC insurance	746us-gaap_FDICIndemnificationAsset	739us-gaap_FDICIndemnificationAsset
Accrued federal and state tax receivable	5,055us-gaap_IncomeTaxReceivable	5,343us-gaap_IncomeTaxReceivable
Derivative assets	12,443us-gaap_DerivativeAssets	8,318us-gaap_DerivativeAssets
Assets held for sale	1,280	3,969
Other	11,490us-gaap_OtherAssetsMiscellaneous	10,687us-gaap_OtherAssetsMiscellaneous
Total other assets	$ 61,090us-gaap_OtherAssets	$ 54,009us-gaap_OtherAssets

Represents the investment in tax credits as of the balance sheet date.

No definition available.

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- Definition

Represents the sum of the carrying value of all the Assets Held-for-Sale at the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-SubTopic 20

-Section 50

-Paragraph 1

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- Definition

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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- Definition

Carrying amount of receivable assets originating from the indemnification agreement with the Federal Deposit Insurance Corporation (FDIC), in which the FDIC is to partially cover losses.

+ References

No definition available.

+ Details

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- Definition

Carrying amount as of the balance sheet date of income taxes previously overpaid to tax authorities (such as U.S. Federal, state and local tax authorities) representing refunds of overpayments or recoveries based on agreed-upon resolutions of disputes. Also called income tax refund receivable.

+ References

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- Definition

Carrying amount as of the balance sheet date of interest earned but not received. Also called accrued interest or accrued interest receivable.

+ References

+ Details

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- Definition

The aggregate carrying amounts, as of the balance sheet date, of assets not separately disclosed in the balance sheet.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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- Definition

Amount of other miscellaneous assets.

+ References

No definition available.

+ Details

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- Definition

Amortized amount of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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+ Details

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