XML 54 R42.htm IDEA: XBRL DOCUMENT
v3.24.3

SECURITIES AVAILABLE FOR SALE, HELD TO MATURITY, AND EQUITY SECURITIES - Schedule of Debt Securities, Held-to-maturity, Allowance for Credit Loss (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2024 | Sep. 30, 2023 | Sep. 30, 2024 | Sep. 30, 2023
Total |  |  |  |
Beginning balance | $ 65 | $ 71 | $ 68 | $ 91
Provision (benefit) for credit losses | 0 | (2) | (3) | (22)
Ending balance | 65 | 69 | 65 | 69
Municipal bonds and obligations |  |  |  |
Total |  |  |  |
Beginning balance | 45 | 49 | 48 | 66
Provision (benefit) for credit losses | 0 | (1) | (3) | (18)
Ending balance | 45 | 48 | 45 | 48
Tax advantaged economic development bonds |  |  |  |
Total |  |  |  |
Beginning balance | 20 | 22 | 20 | 25
Provision (benefit) for credit losses | 0 | (1) | 0 | (4)
Ending balance | $ 20 | $ 21 | $ 20 | $ 21

X
- Definition Amount, excluding accrued interest, of allowance for credit loss on investment in debt security measured at amortized cost (held-to-maturity). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479344/326-20-45-1 + Details
Name: | us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
Name: | us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of expense (reversal of expense) for expected credit loss on investment in debt security measured at amortized cost (held-to-maturity). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-13 + Details
Name: | us-gaap_DebtSecuritiesHeldToMaturityCreditLossExpenseReversal
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=bhlb_TaxAdvantagedEconomicDevelopmentBondsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |