$BHLB
BERKSHIRE HILLS BANCORP INC Stock $bhlb

$bhlb Overview Financials Valuation SEC Filings Company Website

2021 Q3 Form 10-Q Financial Statement

#000110813421000025 Filed on November 09, 2021

Income Statement

Concept	2021 Q3	2021 Q2	2020 Q3
Revenue	$145.0M	$97.40M	$97.02M
YoY Change	49.46%	2.56%	-17.97%
Cost Of Revenue
YoY Change
Gross Profit
YoY Change
Gross Profit Margin
Selling, General & Admin
YoY Change
% of Gross Profit
Research & Development	$8.397M	$8.214M	$8.540M
YoY Change	-1.67%	5.92%	24.69%
% of Gross Profit
Depreciation & Amortization	$4.100M	$4.100M	$4.600M
YoY Change	-10.87%	-12.77%	6.98%
% of Gross Profit
Operating Expenses	$8.397M	$8.214M	$8.540M
YoY Change	-1.67%	5.92%	24.69%
Operating Profit
YoY Change
Interest Expense	$8.320M	$9.971M	$20.71M
YoY Change	-59.83%	-61.79%	-43.8%
% of Operating Profit
Other Income/Expense, Net	$1.279M	$2.211M	$1.927M
YoY Change	-33.63%	-321.32%
Pretax Income	$79.54M	$28.53M	$22.98M
YoY Change	246.22%	-105.1%	-6.86%
Income Tax	$15.79M	$6.896M	-$68.00K
% Of Pretax Income	19.86%	24.17%	-0.3%
Net Earnings	$63.75M	$21.64M	$21.23M
YoY Change	200.35%	-103.94%	-6.15%
Net Earnings / Revenue	43.96%	22.21%	21.88%
Basic Earnings Per Share	$1.32	$0.43	$0.42
Diluted Earnings Per Share	$1.31	$0.43	$0.42
COMMON SHARES
Basic Shares Outstanding	48.40M shares	50.32M shares	50.33M shares
Diluted Shares Outstanding	48.74M shares	50.61M shares	50.33M shares

Balance Sheet

Concept	2021 Q3	2021 Q2	2020 Q3
SHORT-TERM ASSETS
Cash & Short-Term Investments	$2.140B	$1.842B	$967.3M
YoY Change	121.25%	71.0%	167.43%
Cash & Equivalents	$2.125B	$1.827B	$935.3M
Short-Term Investments	$15.60M	$15.71M	$31.99M
Other Short-Term Assets
YoY Change
Inventory
Prepaid Expenses
Receivables
Other Receivables
Total Short-Term Assets
YoY Change
LONG-TERM ASSETS
Property, Plant & Equipment	$99.23M	$104.7M	$117.1M
YoY Change	-15.27%	-11.83%	-4.93%
Goodwill			$0.00
YoY Change			-100.0%
Intangibles	$30.91M	$32.20M	$40.95M
YoY Change	-24.52%	-24.19%	-13.24%
Long-Term Investments
YoY Change
Other Assets	$4.000M	$277.0M	$13.00M
YoY Change	-69.23%	1159.09%	-95.55%
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets	$11.85B	$12.27B	$12.61B
YoY Change	-6.09%	-6.05%	-6.78%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable
YoY Change
Accrued Expenses	$57.00M	$61.00M	$76.00M
YoY Change	-25.0%	-22.78%	-8.43%
Deferred Revenue
YoY Change
Short-Term Debt	$0.00	$0.00	$110.0M
YoY Change	-100.0%	-100.0%	-63.33%
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$57.00M	$61.00M	$76.00M
YoY Change	-25.0%	-22.78%	-8.43%
LONG-TERM LIABILITIES
Long-Term Debt	$107.0M	$108.0M	$108.0M
YoY Change	-0.93%	0.0%	0.0%
Other Long-Term Liabilities	$124.0M	$797.0M	$179.0M
YoY Change	-30.73%	267.28%	-25.73%
Total Long-Term Liabilities	$231.0M	$905.0M	$287.0M
YoY Change	-19.51%	178.46%	-17.77%
TOTAL LIABILITIES
Total Short-Term Liabilities	$57.00M	$61.00M	$76.00M
Total Long-Term Liabilities	$231.0M	$905.0M	$287.0M
Total Liabilities	$10.67B	$11.10B	$11.44B
YoY Change	-6.71%	-6.73%	-2.76%
SHAREHOLDERS EQUITY
Retained Earnings	-$153.4M	-$211.0M	-$242.2M
YoY Change	-36.64%	-18.01%	-169.8%
Common Stock	$1.424B	$1.424B	$1.423B
YoY Change	0.07%	-0.32%	0.0%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$90.15M	$40.99M	$46.85M
YoY Change	92.42%	-21.2%	4.9%
Treasury Stock Shares	3.246M shares	1.450M shares	1.597M shares
Shareholders Equity	$1.178B	$1.175B	$1.179B
YoY Change
Total Liabilities & Shareholders Equity	$11.85B	$12.27B	$12.61B
YoY Change	-6.09%	-6.05%	-6.78%

Cashflow Statement

Concept	2021 Q3	2021 Q2	2020 Q3
OPERATING ACTIVITIES
Net Income	$63.75M	$21.64M	$21.23M
YoY Change	200.35%	-103.94%	-6.15%
Depreciation, Depletion And Amortization	$4.100M	$4.100M	$4.600M
YoY Change	-10.87%	-12.77%	6.98%
Cash From Operating Activities	$18.80M	$40.10M	$17.60M
YoY Change	6.82%	-71.78%	-40.94%
INVESTING ACTIVITIES
Capital Expenditures	$0.00	$700.0K	-$1.700M
YoY Change	-100.0%	-163.64%	-61.36%
Acquisitions
YoY Change
Other Investing Activities	$83.00M	$391.3M	$310.8M
YoY Change	-73.29%	-322.33%	38.07%
Cash From Investing Activities	$83.00M	$392.0M	$309.1M
YoY Change	-73.15%	-321.34%	40.05%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	196.1M	-505.2M	-435.6M
YoY Change	-145.02%	-206.63%	145.13%
NET CHANGE
Cash From Operating Activities	18.80M	40.10M	17.60M
Cash From Investing Activities	83.00M	392.0M	309.1M
Cash From Financing Activities	196.1M	-505.2M	-435.6M
Net Change In Cash	297.9M	-73.10M	-108.9M
YoY Change	-373.55%	-116.66%	-249.59%
FREE CASH FLOW
Cash From Operating Activities	$18.80M	$40.10M	$17.60M
Capital Expenditures	$0.00	$700.0K	-$1.700M
Free Cash Flow	$18.80M	$39.40M	$19.30M
YoY Change	-2.59%	-72.49%	-43.57%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
	dei	Entity Central Index Key EntityCentralIndexKey	0001108134
	dei	Amendment Flag AmendmentFlag	false
	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2021
	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	Q3
CY2019	us-gaap	Accounting Standards Update Extensible List AccountingStandardsUpdateExtensibleList	http://fasb.org/us-gaap/2021-01-31#AccountingStandardsUpdate201613Member
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CY2020Q4	us-gaap	Finance Lease Right Of Use Asset Statement Of Financial Position Extensible List FinanceLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2021-01-31#PropertyPlantAndEquipmentNet
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CY2021Q3	us-gaap	Finance Lease Liability Statement Of Financial Position Extensible List FinanceLeaseLiabilityStatementOfFinancialPositionExtensibleList	http://fasb.org/us-gaap/2021-01-31#OtherLiabilities
	dei	Document Type DocumentType	10-Q
	dei	Document Quarterly Report DocumentQuarterlyReport	true
	dei	Document Period End Date DocumentPeriodEndDate	2021-09-30
	dei	Document Transition Report DocumentTransitionReport	false
	dei	Entity File Number EntityFileNumber	001-15781
	dei	Entity Registrant Name EntityRegistrantName	BERKSHIRE HILLS BANCORP, INC.
	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	DE
	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	04-3510455
	dei	Entity Address Address Line1 EntityAddressAddressLine1	60 State Street
	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
	dei	Entity Address City Or Town EntityAddressCityOrTown	Boston
	dei	Entity Address State Or Province EntityAddressStateOrProvince	MA
	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	02109
	dei	City Area Code CityAreaCode	800
	dei	Local Phone Number LocalPhoneNumber	773-5601
	dei	Security12b Title Security12bTitle	Common Stock, par value $0.01 per share
	dei	Trading Symbol TradingSymbol	BHLB
	dei	Security Exchange Name SecurityExchangeName	NYSE
	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
	dei	Entity Filer Category EntityFilerCategory	Accelerated Filer
	dei	Entity Small Business EntitySmallBusiness	false
	dei	Entity Shell Company EntityShellCompany	false
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	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	492000	USD
CY2021Q3	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	-166000	USD
CY2020Q3	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	-1017000	USD
	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	-681000	USD
	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	-9925000	USD
CY2021Q3	us-gaap	Gain Loss On Sale Of Business GainLossOnSaleOfBusiness	51885000	USD
CY2020Q3	us-gaap	Gain Loss On Sale Of Business GainLossOnSaleOfBusiness	0	USD
	us-gaap	Gain Loss On Sale Of Business GainLossOnSaleOfBusiness	51885000	USD
	us-gaap	Gain Loss On Sale Of Business GainLossOnSaleOfBusiness	0	USD
CY2021Q3	us-gaap	Noninterest Income NoninterestIncome	73635000	USD
CY2020Q3	us-gaap	Noninterest Income NoninterestIncome	19963000	USD
	us-gaap	Noninterest Income NoninterestIncome	121839000	USD
	us-gaap	Noninterest Income NoninterestIncome	42980000	USD
CY2021Q3	us-gaap	Revenues Revenues	145003000	USD
CY2020Q3	us-gaap	Revenues Revenues	97018000	USD
	us-gaap	Revenues Revenues	343693000	USD
	us-gaap	Revenues Revenues	284053000	USD
CY2021Q3	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	-4000000	USD
CY2020Q3	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	1200000	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	2500000	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	65878000	USD
CY2021Q3	us-gaap	Labor And Related Expense LaborAndRelatedExpense	37068000	USD
CY2020Q3	us-gaap	Labor And Related Expense LaborAndRelatedExpense	34809000	USD
	us-gaap	Labor And Related Expense LaborAndRelatedExpense	112773000	USD
	us-gaap	Labor And Related Expense LaborAndRelatedExpense	111121000	USD
CY2021Q3	bhlb	Occupancy And Equipment OccupancyAndEquipment	10421000	USD
CY2020Q3	bhlb	Occupancy And Equipment OccupancyAndEquipment	11084000	USD
	bhlb	Occupancy And Equipment OccupancyAndEquipment	32044000	USD
	bhlb	Occupancy And Equipment OccupancyAndEquipment	32411000	USD
CY2021Q3	us-gaap	Communications And Information Technology CommunicationsAndInformationTechnology	8397000	USD
CY2020Q3	us-gaap	Communications And Information Technology CommunicationsAndInformationTechnology	8540000	USD
	us-gaap	Communications And Information Technology CommunicationsAndInformationTechnology	25204000	USD
	us-gaap	Communications And Information Technology CommunicationsAndInformationTechnology	24376000	USD
CY2021Q3	us-gaap	Marketing Expense MarketingExpense	860000	USD
CY2020Q3	us-gaap	Marketing Expense MarketingExpense	1002000	USD
	us-gaap	Marketing Expense MarketingExpense	1973000	USD
	us-gaap	Marketing Expense MarketingExpense	3069000	USD
CY2021Q3	us-gaap	Professional Fees ProfessionalFees	3180000	USD
CY2020Q3	us-gaap	Professional Fees ProfessionalFees	2567000	USD
	us-gaap	Professional Fees ProfessionalFees	13495000	USD
	us-gaap	Professional Fees ProfessionalFees	7852000	USD
CY2021Q3	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	805000	USD
CY2020Q3	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	1518000	USD
	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	2852000	USD
	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	4658000	USD
CY2021Q3	bhlb	Other Real Estate Owned OtherRealEstateOwned	41000	USD
CY2020Q3	bhlb	Other Real Estate Owned OtherRealEstateOwned	40000	USD
	bhlb	Other Real Estate Owned OtherRealEstateOwned	17000	USD
	bhlb	Other Real Estate Owned OtherRealEstateOwned	81000	USD
CY2021Q3	us-gaap	Adjustment For Amortization AdjustmentForAmortization	1296000	USD
CY2020Q3	us-gaap	Adjustment For Amortization AdjustmentForAmortization	1530000	USD
	us-gaap	Adjustment For Amortization AdjustmentForAmortization	3912000	USD
	us-gaap	Adjustment For Amortization AdjustmentForAmortization	4668000	USD
CY2021Q3	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	USD
CY2020Q3	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	USD
	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	USD
	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	553762000	USD
CY2021Q3	us-gaap	Other Nonrecurring Expense OtherNonrecurringExpense	1425000	USD
CY2020Q3	us-gaap	Other Nonrecurring Expense OtherNonrecurringExpense	5316000	USD
	us-gaap	Other Nonrecurring Expense OtherNonrecurringExpense	4917000	USD
	us-gaap	Other Nonrecurring Expense OtherNonrecurringExpense	5316000	USD
CY2021Q3	us-gaap	Other Noninterest Expense OtherNoninterestExpense	5967000	USD
CY2020Q3	us-gaap	Other Noninterest Expense OtherNoninterestExpense	6437000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	19299000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	21129000	USD
CY2021Q3	us-gaap	Noninterest Expense NoninterestExpense	69460000	USD
CY2020Q3	us-gaap	Noninterest Expense NoninterestExpense	72843000	USD
	us-gaap	Noninterest Expense NoninterestExpense	216486000	USD
	us-gaap	Noninterest Expense NoninterestExpense	768443000	USD
CY2021Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	79543000	USD
	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	98416000	USD
CY2020Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	22975000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	124707000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	-550268000	USD
CY2021Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	15794000	USD
CY2020Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-68000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	26291000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-18194000	USD
CY2021Q3	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	63749000	USD
CY2020Q3	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	23043000	USD
	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	-532074000	USD
CY2021Q3	us-gaap	Discontinued Operation Income Loss From Discontinued Operation During Phase Out Period Before Income Tax DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodBeforeIncomeTax	0	USD
CY2020Q3	us-gaap	Discontinued Operation Income Loss From Discontinued Operation During Phase Out Period Before Income Tax DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodBeforeIncomeTax	-2477000	USD
	us-gaap	Discontinued Operation Income Loss From Discontinued Operation During Phase Out Period Before Income Tax DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodBeforeIncomeTax	0	USD
	us-gaap	Discontinued Operation Income Loss From Discontinued Operation During Phase Out Period Before Income Tax DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodBeforeIncomeTax	-21741000	USD
CY2021Q3	us-gaap	Discontinued Operation Tax Effect Of Discontinued Operation DiscontinuedOperationTaxEffectOfDiscontinuedOperation	0	USD
CY2020Q3	us-gaap	Discontinued Operation Tax Effect Of Discontinued Operation DiscontinuedOperationTaxEffectOfDiscontinuedOperation	-659000	USD
	us-gaap	Discontinued Operation Tax Effect Of Discontinued Operation DiscontinuedOperationTaxEffectOfDiscontinuedOperation	0	USD
	us-gaap	Discontinued Operation Tax Effect Of Discontinued Operation DiscontinuedOperationTaxEffectOfDiscontinuedOperation	-5789000	USD
CY2021Q3	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	0	USD
CY2020Q3	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-1818000	USD
	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	0	USD
	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-15952000	USD
CY2021Q3	us-gaap	Net Income Loss NetIncomeLoss	63749000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	21225000	USD
	us-gaap	Net Income Loss NetIncomeLoss	98416000	USD
	us-gaap	Net Income Loss NetIncomeLoss	-548026000	USD
CY2021Q3	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	0	USD
CY2020Q3	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	58000	USD
	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	0	USD
	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	313000	USD
CY2021Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	63749000	USD
CY2020Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	21167000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	98416000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	-548339000	USD
CY2021Q3	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	1.32
CY2020Q3	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.46
	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	1.98
	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	-10.58
CY2021Q3	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	0
CY2020Q3	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	-0.04
	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	0
	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	-0.32
CY2021Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.32
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.42
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.98
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-10.90
CY2021Q3	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	1.31
CY2020Q3	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.46
	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	1.97
	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	-10.58
CY2021Q3	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerDilutedShare	0
CY2020Q3	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerDilutedShare	-0.04
	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerDilutedShare	0
	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerDilutedShare	-0.32
CY2021Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.31
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.42
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.97
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-10.90
CY2021Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	48395000	shares
CY2020Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	50329000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	49672000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	50256000	shares
CY2021Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	48744000	shares
CY2020Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	50329000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	49963000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	50256000	shares
CY2021Q3	us-gaap	Net Income Loss NetIncomeLoss	63749000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	21225000	USD
	us-gaap	Net Income Loss NetIncomeLoss	98416000	USD
	us-gaap	Net Income Loss NetIncomeLoss	-548026000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-10098000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-1085000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-31718000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	27529000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-2575000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-272000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-8096000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	7096000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-7523000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-813000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-23622000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	20433000	USD
CY2021Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	56226000	USD
CY2020Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	20412000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	74794000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-527593000	USD
CY2020Q2	us-gaap	Stockholders Equity StockholdersEquity	1164140000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	21225000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-813000	USD
CY2020Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	20412000	USD
CY2020Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.12
CY2020Q3	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	5993000	USD
CY2020Q3	us-gaap	Preferred Stock Dividends Per Share Declared PreferredStockDividendsPerShareDeclared	0.24
CY2020Q3	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	58000	USD
CY2020Q3	us-gaap	Stock Issued During Period Value Restricted Stock Award Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardForfeitures	0	USD
CY2020Q3	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	0	USD
CY2020Q3	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	0	USD
CY2020Q3	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	635000	USD
CY2020Q3	us-gaap	Stockholders Equity Other StockholdersEquityOther	111000	USD
CY2020Q3	us-gaap	Stockholders Equity StockholdersEquity	1179025000	USD
CY2021Q2	us-gaap	Stockholders Equity StockholdersEquity	1175389000	USD
CY2021Q3	us-gaap	Net Income Loss NetIncomeLoss	63749000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-7523000	USD
CY2021Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	56226000	USD
CY2021Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.12
CY2021Q3	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	6187000	USD
CY2021Q3	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	47961000	USD
CY2021Q3	us-gaap	Stock Issued During Period Value Restricted Stock Award Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardForfeitures	-1000	USD
CY2021Q3	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	38000	USD
CY2021Q3	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	0	USD
CY2021Q3	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	1371000	USD
CY2021Q3	us-gaap	Stockholders Equity Other StockholdersEquityOther	802000	USD
CY2021Q3	us-gaap	Stockholders Equity StockholdersEquity	1178075000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	1758564000	USD
	us-gaap	Net Income Loss NetIncomeLoss	-548026000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	20433000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-527593000	USD
	us-gaap	Stock Issued During Period Value Conversion Of Convertible Securities StockIssuedDuringPeriodValueConversionOfConvertibleSecurities	0	USD
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.60
	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	30143000	USD
	us-gaap	Preferred Stock Dividends Per Share Declared PreferredStockDividendsPerShareDeclared	1.20
	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	313000	USD
	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	473000	USD
	us-gaap	Stock Issued During Period Value Restricted Stock Award Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardForfeitures	0	USD
	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	607000	USD
	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	0	USD
	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	3450000	USD
	us-gaap	Stockholders Equity Other StockholdersEquityOther	694000	USD
CY2020Q3	us-gaap	Stockholders Equity StockholdersEquity	1179025000	USD
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	1187773000	USD
	us-gaap	Net Income Loss NetIncomeLoss	98416000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-23622000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	74794000	USD
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.36
	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	18411000	USD
	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	68712000	USD
	us-gaap	Stock Issued During Period Value Restricted Stock Award Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardForfeitures	0	USD
	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	162000	USD
	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	0	USD
	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	3652000	USD
	us-gaap	Stockholders Equity Other StockholdersEquityOther	1183000	USD
CY2021Q3	us-gaap	Stockholders Equity StockholdersEquity	1178075000	USD
	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	98416000	USD
	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	-532074000	USD
	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	0	USD
	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-15952000	USD
	us-gaap	Net Income Loss NetIncomeLoss	98416000	USD
	us-gaap	Net Income Loss NetIncomeLoss	-548026000	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	2500000	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	65878000	USD
	bhlb	Amortizationof Securities AmortizationofSecurities	1533000	USD
	bhlb	Amortizationof Securities AmortizationofSecurities	2035000	USD
	bhlb	Change In Unamortized Net Loan Costs And Premiums ChangeInUnamortizedNetLoanCostsAndPremiums	4772000	USD
	bhlb	Change In Unamortized Net Loan Costs And Premiums ChangeInUnamortizedNetLoanCostsAndPremiums	-20565000	USD
	us-gaap	Other Depreciation And Amortization OtherDepreciationAndAmortization	8406000	USD
	us-gaap	Other Depreciation And Amortization OtherDepreciationAndAmortization	8944000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	3652000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	3450000	USD
	bhlb	Accretionof Purchase Accounting Entries AccretionofPurchaseAccountingEntries	-5046000	USD
	bhlb	Accretionof Purchase Accounting Entries AccretionofPurchaseAccountingEntries	-8146000	USD
	us-gaap	Adjustment For Amortization AdjustmentForAmortization	3912000	USD
	us-gaap	Adjustment For Amortization AdjustmentForAmortization	4668000	USD
	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	4210000	USD
	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	3876000	USD
	us-gaap	Marketable Securities Realized Gain Loss MarketableSecuritiesRealizedGainLoss	-681000	USD
	us-gaap	Marketable Securities Realized Gain Loss MarketableSecuritiesRealizedGainLoss	-9925000	USD
	us-gaap	Increase Decrease In Loans Held For Sale IncreaseDecreaseInLoansHeldForSale	-6752000	USD
	us-gaap	Increase Decrease In Loans Held For Sale IncreaseDecreaseInLoansHeldForSale	7130000	USD
	us-gaap	Gain Loss On Disposition Of Assets GainLossOnDispositionOfAssets	-2811000	USD
	us-gaap	Gain Loss On Disposition Of Assets GainLossOnDispositionOfAssets	-327000	USD
	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	-6000	USD
	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	-13000	USD
	bhlb	Amortization Of Tax Credits AmortizationOfTaxCredits	1996000	USD
	bhlb	Amortization Of Tax Credits AmortizationOfTaxCredits	2621000	USD
	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	USD
	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	553762000	USD
	us-gaap	Gain Loss On Sale Of Business GainLossOnSaleOfBusiness	51885000	USD
	us-gaap	Gain Loss On Sale Of Business GainLossOnSaleOfBusiness	0	USD
	us-gaap	Federal Home Loan Bank Advances General Debt Obligations Disclosures Repayment And Penalties FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresRepaymentAndPenalties	862000	USD
	us-gaap	Federal Home Loan Bank Advances General Debt Obligations Disclosures Repayment And Penalties FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresRepaymentAndPenalties	0	USD
	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-16934000	USD
	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	36089000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities Continuing Operations NetCashProvidedByUsedInOperatingActivitiesContinuingOperations	82548000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities Continuing Operations NetCashProvidedByUsedInOperatingActivitiesContinuingOperations	84873000	USD
	us-gaap	Cash Provided By Used In Operating Activities Discontinued Operations CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations	0	USD
	us-gaap	Cash Provided By Used In Operating Activities Discontinued Operations CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations	109897000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	82548000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	194770000	USD
	us-gaap	Increase Decrease In Trading Securities IncreaseDecreaseInTradingSecurities	-578000	USD
	us-gaap	Increase Decrease In Trading Securities IncreaseDecreaseInTradingSecurities	-546000	USD
	us-gaap	Payments To Acquire Marketable Securities PaymentsToAcquireMarketableSecurities	0	USD
	us-gaap	Payments To Acquire Marketable Securities PaymentsToAcquireMarketableSecurities	17631000	USD
	us-gaap	Proceeds From Sale And Maturity Of Marketable Securities ProceedsFromSaleAndMaturityOfMarketableSecurities	2880000	USD
	us-gaap	Proceeds From Sale And Maturity Of Marketable Securities ProceedsFromSaleAndMaturityOfMarketableSecurities	18458000	USD
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	428950000	USD
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	635194000	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	0	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	71844000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	448446000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	320010000	USD
	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	219471000	USD
	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	3200000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	31222000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	29237000	USD
	us-gaap	Proceeds From Loan And Lease Originations And Principal Collections1 ProceedsFromLoanAndLeaseOriginationsAndPrincipalCollections1	1256178000	USD
	us-gaap	Proceeds From Loan And Lease Originations And Principal Collections1 ProceedsFromLoanAndLeaseOriginationsAndPrincipalCollections1	474707000	USD
	bhlb	Increase Decrease In Loans Held For Sale Investing Activities IncreaseDecreaseInLoansHeldForSaleInvestingActivities	-50914000	USD
	bhlb	Increase Decrease In Loans Held For Sale Investing Activities IncreaseDecreaseInLoansHeldForSaleInvestingActivities	0	USD
	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	1578000	USD
	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	553000	USD
	us-gaap	Payments To Acquire Federal Reserve Stock PaymentsToAcquireFederalReserveStock	0	USD
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	6190000	USD
	us-gaap	Proceeds From Sale Of Loans Held For Sale ProceedsFromSaleOfLoansHeldForSale	17480000	USD
	us-gaap	Payments To Acquire Federal Reserve Stock PaymentsToAcquireFederalReserveStock	6741000	USD
	us-gaap	Proceeds From Sale Of Federal Reserve Stock ProceedsFromSaleOfFederalReserveStock	22832000	USD
	us-gaap	Proceeds From Sale Of Federal Reserve Stock ProceedsFromSaleOfFederalReserveStock	14240000	USD
	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	1385000	USD
	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	6499000	USD
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	1606000	USD
	us-gaap	Proceeds From Sale Of Loans Held For Sale ProceedsFromSaleOfLoansHeldForSale	37988000	USD
	us-gaap	Proceeds From Sale Of Other Real Estate ProceedsFromSaleOfOtherRealEstate	187000	USD
	us-gaap	Proceeds From Sale Of Other Real Estate ProceedsFromSaleOfOtherRealEstate	171000	USD
	bhlb	Payments For Disposal Of Business Settlement Amount PaymentsForDisposalOfBusinessSettlementAmount	352814000	USD
	bhlb	Payments For Disposal Of Business Settlement Amount PaymentsForDisposalOfBusinessSettlementAmount	0	USD
	us-gaap	Net Cash Provided By Used In Investing Activities Continuing Operations NetCashProvidedByUsedInInvestingActivitiesContinuingOperations	828069000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities Continuing Operations NetCashProvidedByUsedInInvestingActivitiesContinuingOperations	292299000	USD
	us-gaap	Cash Provided By Used In Investing Activities Discontinued Operations CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations	0	USD
	us-gaap	Cash Provided By Used In Investing Activities Discontinued Operations CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations	0	USD
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	142410000	USD
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	133031000	USD
	bhlb	Increase Decrease In Loans Held For Sale Financing Activities IncreaseDecreaseInLoansHeldForSaleFinancingActivities	-20953000	USD
	bhlb	Increase Decrease In Loans Held For Sale Financing Activities IncreaseDecreaseInLoansHeldForSaleFinancingActivities	0	USD
	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	0	USD
	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	326277000	USD
	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	462017000	USD
	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	451493000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	68712000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	473000	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	162000	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	607000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	18411000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	30456000	USD
	bhlb	Settlementof Derivative Contractswith Institutional Counterparties SettlementofDerivativeContractswithInstitutionalCounterparties	-41653000	USD
	bhlb	Settlementof Derivative Contractswith Institutional Counterparties SettlementofDerivativeContractswithInstitutionalCounterparties	109099000	USD
CY2020Q4	us-gaap	Trading Securities Debt Amortized Cost TradingSecuritiesDebtAmortizedCost	8700000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-343962000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-131606000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	566655000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	355463000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	1557875000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	579829000	USD
CY2021Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	2124530000	USD
CY2020Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	935292000	USD
	bhlb	Interest Paid On Deposits InterestPaidOnDeposits	23769000	USD
	bhlb	Interest Paid On Deposits InterestPaidOnDeposits	67119000	USD
	us-gaap	Interest Paid Net InterestPaidNet	9671000	USD
	us-gaap	Interest Paid Net InterestPaidNet	16961000	USD
	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	58000	USD
	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	345000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-23622000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	20433000	USD
CY2020	us-gaap	Equity Securities Fv Ni Unrealized Gain EquitySecuritiesFvNiUnrealizedGain	767000	USD
CY2021Q3	us-gaap	Trading Securities Debt TradingSecuritiesDebt	8600000	USD
	us-gaap	Transfer Of Portfolio Loans And Leases To Held For Sale1 TransferOfPortfolioLoansAndLeasesToHeldForSale1	11660000	USD
	us-gaap	Transfer Of Portfolio Loans And Leases To Held For Sale1 TransferOfPortfolioLoansAndLeasesToHeldForSale1	10048000	USD
	bhlb	Real Estate Owned Acquired In Settlement Of Loans RealEstateOwnedAcquiredInSettlementOfLoans	0	USD
	bhlb	Real Estate Owned Acquired In Settlement Of Loans RealEstateOwnedAcquiredInSettlementOfLoans	224000	USD
	us-gaap	Use Of Estimates UseOfEstimates	<div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:11pt;font-style:italic;font-weight:700;line-height:120%">Use of Estimates</span></div><div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:11pt;font-weight:400;line-height:120%">The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent liabilities at the date of the financial statements. Actual results could differ from those estimates.</span></div>
CY2021Q3	us-gaap	Trading Securities Debt Amortized Cost TradingSecuritiesDebtAmortizedCost	8100000	USD
CY2020Q4	us-gaap	Trading Securities Debt TradingSecuritiesDebt	9700000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss	1633440000	USD
CY2021Q3	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	24704000	USD
CY2021Q3	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	14179000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	1643965000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Amortized Cost Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest	0	USD
CY2021Q3	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss	651863000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	21167000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	7671000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	665359000	USD
CY2021Q3	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	125000	USD
CY2021Q3	us-gaap	Equity Securities Fv Ni Cost EquitySecuritiesFvNiCost	15690000	USD
	us-gaap	Equity Securities Fv Ni Unrealized Gain EquitySecuritiesFvNiUnrealizedGain	105000	USD
	us-gaap	Equity Securities Fv Ni Unrealized Loss EquitySecuritiesFvNiUnrealizedLoss	194000	USD
CY2021Q3	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	15601000	USD
CY2021Q3	bhlb	Debt Securities Available For Sale And Held To Maturity And Equity Securities Fvni Amortized Cost Excluding Accrued Interest DebtSecuritiesAvailableForSaleAndHeldToMaturityAndEquitySecuritiesFVNIAmortizedCostExcludingAccruedInterest	2300993000	USD
CY2021Q3	bhlb	Debt Securities Available For Sale And Held To Maturity And Equity Securities Fvni Accumulated Gross Unrealized Gain Before Tax DebtSecuritiesAvailableForSaleAndHeldToMaturityAndEquitySecuritiesFVNIAccumulatedGrossUnrealizedGainBeforeTax	45976000	USD
CY2021Q3	bhlb	Debt Securities Availableforsaleand Heldtomaturityand Equity Securities Fvni Accumulated Gross Unrealized Lossbefore Tax DebtSecuritiesAvailableforsaleandHeldtomaturityandEquitySecuritiesFVNIAccumulatedGrossUnrealizedLossbeforeTax	22044000	USD
CY2021Q3	bhlb	Debt Securities Available For Sale And Held To Maturity And Equity Securities Fvni Excluding Accrued Interest DebtSecuritiesAvailableForSaleAndHeldToMaturityAndEquitySecuritiesFVNIExcludingAccruedInterest	2324925000	USD
CY2021Q3	bhlb	Debt Securities Available For Sale And Held To Maturity Allowance For Credit Losses Excluding Accrued Interest DebtSecuritiesAvailableForSaleAndHeldToMaturityAllowanceForCreditLossesExcludingAccruedInterest	125000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss	1653977000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	41816000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	561000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	1695232000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest	0	USD
CY2020Q4	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss	465091000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	26976000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	212000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	491855000	USD
CY2020Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	104000	USD
CY2020Q4	us-gaap	Equity Securities Fv Ni Cost EquitySecuritiesFvNiCost	18061000	USD
CY2020	us-gaap	Equity Securities Fv Ni Unrealized Loss EquitySecuritiesFvNiUnrealizedLoss	315000	USD
CY2020Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	18513000	USD
CY2020Q4	bhlb	Debt Securities Available For Sale And Held To Maturity And Equity Securities Fvni Amortized Cost Excluding Accrued Interest DebtSecuritiesAvailableForSaleAndHeldToMaturityAndEquitySecuritiesFVNIAmortizedCostExcludingAccruedInterest	2137129000	USD
CY2020Q4	bhlb	Debt Securities Available For Sale And Held To Maturity And Equity Securities Fvni Accumulated Gross Unrealized Gain Before Tax DebtSecuritiesAvailableForSaleAndHeldToMaturityAndEquitySecuritiesFVNIAccumulatedGrossUnrealizedGainBeforeTax	69559000	USD
CY2020Q4	bhlb	Debt Securities Availableforsaleand Heldtomaturityand Equity Securities Fvni Accumulated Gross Unrealized Lossbefore Tax DebtSecuritiesAvailableforsaleandHeldtomaturityandEquitySecuritiesFVNIAccumulatedGrossUnrealizedLossbeforeTax	1088000	USD
CY2020Q4	bhlb	Debt Securities Available For Sale And Held To Maturity And Equity Securities Fvni Excluding Accrued Interest DebtSecuritiesAvailableForSaleAndHeldToMaturityAndEquitySecuritiesFVNIExcludingAccruedInterest	2205600000	USD
CY2020Q4	bhlb	Debt Securities Available For Sale And Held To Maturity Allowance For Credit Losses Excluding Accrued Interest DebtSecuritiesAvailableForSaleAndHeldToMaturityAllowanceForCreditLossesExcludingAccruedInterest	104000	USD
CY2021Q2	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	130000	USD
CY2021Q3	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	5000	USD
CY2021Q3	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	125000	USD
CY2020Q2	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	113000	USD
CY2020Q3	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	17000	USD
CY2020Q3	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	96000	USD
CY2020Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	104000	USD
	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	-21000	USD
CY2021Q3	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	125000	USD
CY2019Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	0	USD
	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	213000	USD
CY2020Q3	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	96000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis	31218000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities Next Rolling Twelve Months Fair Value AvailableForSaleSecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	31236000	USD
CY2021Q3	bhlb	Held To Maturity Securities Debt Maturities Next Rolling Twelve Months Amortized Cost Basis HeldToMaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCostBasis	1756000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Debt Maturities Next Rolling Twelve Months Fair Value HeldToMaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsFairValue	1758000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis	4741000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Two Through Five Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	4815000	USD
CY2021Q3	bhlb	Held To Maturity Securities Debt Maturities Rolling Year Two Through Five Amortized Cost Basis HeldToMaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCostBasis	3874000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Debt Maturities Rolling Year Two Through Five Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveFairValue	3909000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis	57667000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling Year Six Through Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	59021000	USD
CY2021Q3	bhlb	Held To Maturity Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost Basis HeldToMaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCostBasis	21191000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	2442000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Debt Maturities Rolling Year Six Through Ten Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenFairValue	21885000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis	80596000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities Rolling After Year Ten Fair Value AvailableForSaleSecuritiesDebtMaturitiesRollingAfterYearTenFairValue	86918000	USD
CY2021Q3	bhlb	Held To Maturity Securities Debt Maturities Rolling After Year Ten Amortized Cost Basis HeldToMaturitySecuritiesDebtMaturitiesRollingAfterYearTenAmortizedCostBasis	260098000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Debt Maturities Rolling After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesRollingAfterTenYearsFairValue	273415000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities Single Maturity Date Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis	174222000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities Single Maturity Date AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate	181990000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Debt Maturities Single Maturity Date Amortized Cost Basis HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis	286919000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Debt Maturities Single Maturity Date Fair Value HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValue	300967000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost	1459218000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue	1461975000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Debt Maturities Without Single Maturity Date Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesWithoutSingleMaturityDateNetCarryingAmount	364944000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Debt Maturities Without Single Maturity Date Fair Value HeldToMaturitySecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue	364392000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss	1633440000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	1643965000	USD
CY2021Q3	us-gaap	Debt Securities Held To Maturity Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss	651863000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	665359000	USD
CY2021Q3	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	160000000	USD
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	429000000	USD
CY2021Q3	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	0	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	0	USD
CY2020Q3	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	319200000	USD
CY2020Q3	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	64200000	USD
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	635200000	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	71800000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	0	USD
	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	0	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	704600	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	698600	USD
	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	705400	USD
	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	699900	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	11737000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	731109000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	69475000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	14179000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	800584000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	7671000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	276240000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	0	USD
CY2021Q3	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	0	USD
CY2021Q3	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	7671000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue	276240000	USD
CY2021Q3	bhlb	Debt Securities Availableforsaleand Heldtomaturity Continuous Unrealized Loss Position Lessthan12 Months Accumulated Loss DebtSecuritiesAvailableforsaleandHeldtomaturityContinuousUnrealizedLossPositionLessthan12MonthsAccumulatedLoss	19408000	USD
CY2021Q3	bhlb	Debt Securities Availableforsaleand Heldtomaturity Continuous Unrealized Loss Position Lessthan12 Months DebtSecuritiesAvailableforsaleandHeldtomaturityContinuousUnrealizedLossPositionLessthan12Months	1007349000	USD
CY2021Q3	bhlb	Debt Securities Availableforsaleand Heldtomaturity Continuous Unrealized Loss Position12 Monthsor Longer Accumulated Loss DebtSecuritiesAvailableforsaleandHeldtomaturityContinuousUnrealizedLossPosition12MonthsorLongerAccumulatedLoss	2442000	USD
CY2021Q3	bhlb	Debt Securities Availableforsaleand Heldtomaturity Continuous Unrealized Loss Position12 Monthsor Longer DebtSecuritiesAvailableforsaleandHeldtomaturityContinuousUnrealizedLossPosition12MonthsorLonger	69475000	USD
CY2021Q3	bhlb	Debt Securities Availableforsaleand Heldtomaturity Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableforsaleandHeldtomaturityUnrealizedLossPositionAccumulatedLoss	21850000	USD
CY2021Q3	bhlb	Debt Securities Availableforsaleand Heldtomaturity Unrealized Loss Position DebtSecuritiesAvailableforsaleandHeldtomaturityUnrealizedLossPosition	1076824000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	551000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	174147000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	10000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	1286000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	561000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	175433000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	212000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	55974000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	0	USD
CY2020Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	0	USD
CY2020Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	212000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue	55974000	USD
CY2020Q4	bhlb	Debt Securities Availableforsaleand Heldtomaturity Continuous Unrealized Loss Position Lessthan12 Months Accumulated Loss DebtSecuritiesAvailableforsaleandHeldtomaturityContinuousUnrealizedLossPositionLessthan12MonthsAccumulatedLoss	763000	USD
CY2020Q4	bhlb	Debt Securities Availableforsaleand Heldtomaturity Continuous Unrealized Loss Position Lessthan12 Months DebtSecuritiesAvailableforsaleandHeldtomaturityContinuousUnrealizedLossPositionLessthan12Months	230121000	USD
CY2020Q4	bhlb	Debt Securities Availableforsaleand Heldtomaturity Continuous Unrealized Loss Position12 Monthsor Longer Accumulated Loss DebtSecuritiesAvailableforsaleandHeldtomaturityContinuousUnrealizedLossPosition12MonthsorLongerAccumulatedLoss	10000	USD
CY2020Q4	bhlb	Debt Securities Availableforsaleand Heldtomaturity Continuous Unrealized Loss Position12 Monthsor Longer DebtSecuritiesAvailableforsaleandHeldtomaturityContinuousUnrealizedLossPosition12MonthsorLonger	1286000	USD
CY2020Q4	bhlb	Debt Securities Availableforsaleand Heldtomaturity Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableforsaleandHeldtomaturityUnrealizedLossPositionAccumulatedLoss	773000	USD
CY2020Q4	bhlb	Debt Securities Availableforsaleand Heldtomaturity Unrealized Loss Position DebtSecuritiesAvailableforsaleandHeldtomaturityUnrealizedLossPosition	231407000	USD
CY2021Q3	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	6836235000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	8081519000	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	112916000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	127302000	USD
CY2021Q3	us-gaap	Financing Receivable Excluding Accrued Interest After Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss	6723319000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest After Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss	7954217000	USD
CY2021Q2	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	119044000	USD
CY2021Q3	us-gaap	Allowance For Loan And Lease Losses Write Offs AllowanceForLoanAndLeaseLossesWriteOffs	4334000	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	2201000	USD
CY2021Q3	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	-3995000	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	112916000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	139394000	USD
CY2020Q3	us-gaap	Allowance For Loan And Lease Losses Write Offs AllowanceForLoanAndLeaseLossesWriteOffs	7776000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	1579000	USD
CY2020Q3	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	1217000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	134414000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	127302000	USD
	us-gaap	Allowance For Loan And Lease Losses Write Offs AllowanceForLoanAndLeaseLossesWriteOffs	23042000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	6177000	USD
	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	2479000	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	112916000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	63575000	USD
	us-gaap	Allowance For Loan And Lease Losses Write Offs AllowanceForLoanAndLeaseLossesWriteOffs	27482000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	6796000	USD
	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	66091000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	134414000	USD
CY2021Q2	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	7829000	USD
CY2020Q2	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	8593000	USD
CY2021Q3	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	0	USD
CY2020Q3	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	0	USD
CY2021Q3	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	7829000	USD
CY2020Q3	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	8593000	USD
CY2020Q4	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	7629000	USD
CY2019Q4	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	100000	USD
	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	200000	USD
	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	500000	USD
CY2021Q3	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	7829000	USD
CY2020Q3	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	8593000	USD
CY2021Q3	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	6836235000	USD
CY2020Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss	8081519000	USD
CY2020Q2	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	19713000	USD
CY2020Q3	bhlb	Financing Receivable Troubled Debt Restructuring Principal Payments FinancingReceivableTroubledDebtRestructuringPrincipalPayments	221000	USD
CY2021Q3	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	37147000	USD
CY2021Q3	us-gaap	Financing Receivable Nonaccrual No Allowance FinancingReceivableNonaccrualNoAllowance	14336000	USD
CY2021Q3	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	3803000	USD
CY2021Q3	us-gaap	Financing Receivable Nonaccrual Interest Income FinancingReceivableNonaccrualInterestIncome	0	USD
CY2020Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	64948000	USD
CY2020Q4	us-gaap	Financing Receivable Nonaccrual No Allowance FinancingReceivableNonaccrualNoAllowance	27418000	USD
CY2020Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	11450000	USD
CY2020Q4	us-gaap	Financing Receivable Nonaccrual Interest Income FinancingReceivableNonaccrualInterestIncome	0	USD
CY2021Q2	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	36457000	USD
CY2021Q3	bhlb	Financing Receivable Troubled Debt Restructuring Principal Payments FinancingReceivableTroubledDebtRestructuringPrincipalPayments	663000	USD
CY2021Q3	bhlb	Financing Receivable Troubled Debt Restructuring Status Change FinancingReceivableTroubledDebtRestructuringStatusChange	0	USD
CY2021Q3	bhlb	Financing Receivable Troubled Debt Restructuring Other Increase Decrease FinancingReceivableTroubledDebtRestructuringOtherIncreaseDecrease	-14073000	USD
CY2021Q3	bhlb	Financing Receivable Troubled Debt Restructuring Additions FinancingReceivableTroubledDebtRestructuringAdditions	283000	USD
CY2021Q3	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	22004000	USD
	bhlb	Financing Receivable Troubled Debt Restructuring Status Change FinancingReceivableTroubledDebtRestructuringStatusChange	0	USD
	bhlb	Financing Receivable Troubled Debt Restructuring Other Increase Decrease FinancingReceivableTroubledDebtRestructuringOtherIncreaseDecrease	-14356000	USD
CY2020Q3	bhlb	Financing Receivable Troubled Debt Restructuring Status Change FinancingReceivableTroubledDebtRestructuringStatusChange	0	USD
CY2020Q3	bhlb	Financing Receivable Troubled Debt Restructuring Other Increase Decrease FinancingReceivableTroubledDebtRestructuringOtherIncreaseDecrease	1111000	USD
CY2020Q3	bhlb	Financing Receivable Troubled Debt Restructuring Additions FinancingReceivableTroubledDebtRestructuringAdditions	611000	USD
CY2020Q3	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	21214000	USD
CY2020Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	20548000	USD
	bhlb	Financing Receivable Troubled Debt Restructuring Principal Payments FinancingReceivableTroubledDebtRestructuringPrincipalPayments	1304000	USD
	bhlb	Financing Receivable Troubled Debt Restructuring Additions FinancingReceivableTroubledDebtRestructuringAdditions	17116000	USD
CY2021Q3	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	22004000	USD
CY2019Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	19316000	USD
	bhlb	Financing Receivable Troubled Debt Restructuring Principal Payments FinancingReceivableTroubledDebtRestructuringPrincipalPayments	6092000	USD
	bhlb	Financing Receivable Troubled Debt Restructuring Status Change FinancingReceivableTroubledDebtRestructuringStatusChange	0	USD
	bhlb	Financing Receivable Troubled Debt Restructuring Other Increase Decrease FinancingReceivableTroubledDebtRestructuringOtherIncreaseDecrease	-3601000	USD
	bhlb	Financing Receivable Troubled Debt Restructuring Additions FinancingReceivableTroubledDebtRestructuringAdditions	11591000	USD
CY2020Q3	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	21214000	USD
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	15000	loan
CY2021Q3	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	2000	loan
CY2021Q3	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	283000	USD
CY2021Q3	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	283000	USD
CY2020Q3	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	10000	loan
CY2020Q3	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	611000	USD
CY2020Q3	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	611000	USD
	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	17116000	USD
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	17116000	USD
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	15000	loan
	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	11591000	USD
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	11591000	USD
CY2021Q3	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	1	loan
CY2021Q3	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	10435000	USD
	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	3	loan
	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	10506000	USD
CY2021Q3	us-gaap	Lines Of Credit Current LinesOfCreditCurrent	3000000	USD
CY2021Q3	us-gaap	Time Deposits Less Than100000 TimeDepositsLessThan100000	583893000	USD
CY2020Q4	us-gaap	Time Deposits Less Than100000 TimeDepositsLessThan100000	663324000	USD
CY2021Q3	bhlb	Time Deposits100000 Through250000 TimeDeposits100000Through250000	828625000	USD
CY2020Q4	bhlb	Time Deposits100000 Through250000 TimeDeposits100000Through250000	1219210000	USD
CY2021Q3	bhlb	Time Deposits250000or More TimeDeposits250000orMore	413196000	USD
CY2020Q4	bhlb	Time Deposits250000or More TimeDeposits250000orMore	502551000	USD
CY2021Q3	us-gaap	Time Deposits TimeDeposits	1825714000	USD
CY2020Q4	us-gaap	Time Deposits TimeDeposits	2385085000	USD
CY2021Q3	bhlb	Brokered Time Deposits BrokeredTimeDeposits	317100000	USD
CY2020Q4	bhlb	Brokered Time Deposits BrokeredTimeDeposits	610600000	USD
CY2021Q3	bhlb	Reciprocal Money Market Deposits ReciprocalMoneyMarketDeposits	79200000	USD
CY2020Q4	bhlb	Reciprocal Money Market Deposits ReciprocalMoneyMarketDeposits	119000000	USD
CY2021Q3	us-gaap	Short Term Borrowings ShortTermBorrowings	0	USD
CY2021Q3	us-gaap	Short Term Debt Weighted Average Interest Rate ShortTermDebtWeightedAverageInterestRate	0
CY2020Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	40000000	USD
CY2020Q4	us-gaap	Short Term Debt Weighted Average Interest Rate ShortTermDebtWeightedAverageInterestRate	0.0105
CY2021Q3	us-gaap	Long Term Debt LongTermDebt	110823000	USD
CY2021Q3	us-gaap	Longterm Debt Weighted Average Interest Rate LongtermDebtWeightedAverageInterestRate	0.0532
CY2020Q4	us-gaap	Long Term Debt LongTermDebt	531637000	USD
CY2020Q4	us-gaap	Longterm Debt Weighted Average Interest Rate LongtermDebtWeightedAverageInterestRate	0.0261
CY2021Q3	us-gaap	Debt And Capital Lease Obligations DebtAndCapitalLeaseObligations	110823000	USD
CY2021Q3	us-gaap	Debt Weighted Average Interest Rate DebtWeightedAverageInterestRate	0.0532
CY2020Q4	us-gaap	Debt And Capital Lease Obligations DebtAndCapitalLeaseObligations	571637000	USD
CY2020Q4	us-gaap	Debt Weighted Average Interest Rate DebtWeightedAverageInterestRate	0.0250
CY2021Q3	us-gaap	Payments For Federal Home Loan Bank Advances PaymentsForFederalHomeLoanBankAdvances	94100000	USD
CY2021Q3	us-gaap	Federal Home Loan Bank Advances General Debt Obligations Disclosures Repayment And Penalties FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresRepaymentAndPenalties	862200	USD
CY2021Q3	us-gaap	Derivative Notional Amount DerivativeNotionalAmount	3700000000	USD
CY2021Q3	us-gaap	Derivative Collateral Right To Reclaim Cash DerivativeCollateralRightToReclaimCash	56900000	USD
CY2021Q3	bhlb	Derivative Securities Pledged As Collateral Amortized Cost DerivativeSecuritiesPledgedAsCollateralAmortizedCost	35400000	USD
CY2021Q3	us-gaap	Financial Instruments Owned And Pledged As Collateral At Fair Value FinancialInstrumentsOwnedAndPledgedAsCollateralAtFairValue	35600000	USD
CY2021Q3	us-gaap	Derivative Notional Amount DerivativeNotionalAmount	3741883000	USD
CY2021Q3	us-gaap	Derivative Assets Liabilities At Fair Value Net DerivativeAssetsLiabilitiesAtFairValueNet	54502000	USD
CY2021Q3	bhlb	Fair Value Estimates Impactof Settledto Market Contract FairValueEstimatesImpactofSettledtoMarketContract	56000000	USD
CY2020Q4	us-gaap	Derivative Notional Amount DerivativeNotionalAmount	3857115000	USD
CY2020Q4	us-gaap	Derivative Assets Liabilities At Fair Value Net DerivativeAssetsLiabilitiesAtFairValueNet	94313000	USD
CY2020Q4	bhlb	Fair Value Estimates Impactof Settledto Market Contract FairValueEstimatesImpactofSettledtoMarketContract	97600000	USD
CY2021Q3	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	53583000	USD
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	60018000	USD
CY2021Q3	us-gaap	Finance Lease Right Of Use Asset FinanceLeaseRightOfUseAsset	6805000	USD
CY2020Q4	us-gaap	Finance Lease Right Of Use Asset FinanceLeaseRightOfUseAsset	7197000	USD
CY2021Q3	bhlb	Lease Rightof Use Asset LeaseRightofUseAsset	60388000	USD
CY2020Q4	bhlb	Lease Rightof Use Asset LeaseRightofUseAsset	67215000	USD
CY2021Q3	us-gaap	Operating Lease Liability OperatingLeaseLiability	57144000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	63894000	USD
CY2021Q3	us-gaap	Finance Lease Liability FinanceLeaseLiability	9996000	USD
CY2020Q4	us-gaap	Finance Lease Liability FinanceLeaseLiability	10383000	USD
CY2021Q3	bhlb	Lease Liability LeaseLiability	67140000	USD
CY2020Q4	bhlb	Lease Liability LeaseLiability	74277000	USD
CY2021Q3	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P9Y8M12D
CY2020Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P9Y9M18D
CY2021Q3	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P13Y1M6D
CY2020Q4	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P13Y9M18D
CY2021Q3	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0284
CY2020Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0281
CY2021Q3	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.0500
CY2020Q4	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.0500
CY2021Q3	us-gaap	Operating Lease Cost OperatingLeaseCost	2600000	USD
	us-gaap	Operating Lease Cost OperatingLeaseCost	8300000	USD
CY2020Q3	us-gaap	Operating Lease Cost OperatingLeaseCost	3400000	USD
	us-gaap	Operating Lease Cost OperatingLeaseCost	10200000	USD
CY2021Q3	us-gaap	Operating Lease Payments OperatingLeasePayments	2524000	USD
CY2020Q3	us-gaap	Operating Lease Payments OperatingLeasePayments	2441000	USD
CY2021Q3	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	126000	USD
CY2020Q3	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	133000	USD
CY2021Q3	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	132000	USD
CY2020Q3	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	125000	USD
	us-gaap	Operating Lease Payments OperatingLeasePayments	8358000	USD
	us-gaap	Operating Lease Payments OperatingLeasePayments	10461000	USD
	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	379000	USD
	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	399000	USD
	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	394000	USD
	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	374000	USD
CY2021Q3	us-gaap	Lessee Operating Lease Liability Payments Remainder Of Fiscal Year LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear	2536000	USD
CY2021Q3	us-gaap	Finance Lease Liability Payments Remainder Of Fiscal Year FinanceLeaseLiabilityPaymentsRemainderOfFiscalYear	257000	USD
CY2021Q3	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	9686000	USD
CY2021Q3	us-gaap	Finance Lease Liability Payments Due Next Twelve Months FinanceLeaseLiabilityPaymentsDueNextTwelveMonths	1031000	USD
CY2021Q3	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	8494000	USD
CY2021Q3	us-gaap	Finance Lease Liability Payments Due Year Two FinanceLeaseLiabilityPaymentsDueYearTwo	1037000	USD
CY2021Q3	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	7451000	USD
CY2021Q3	us-gaap	Finance Lease Liability Payments Due Year Three FinanceLeaseLiabilityPaymentsDueYearThree	1037000	USD
CY2021Q3	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	5764000	USD
CY2021Q3	us-gaap	Finance Lease Liability Payments Due Year Four FinanceLeaseLiabilityPaymentsDueYearFour	1037000	USD
CY2021Q3	bhlb	Lessee Operating Lease Liabilitytobe Paid After Year Four LesseeOperatingLeaseLiabilitytobePaidAfterYearFour	32049000	USD
CY2021Q3	bhlb	Finance Lease Liabilitytobe Paid After Year Four FinanceLeaseLiabilitytobePaidAfterYearFour	9223000	USD
CY2021Q3	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	65980000	USD
	us-gaap	Other Comprehensive Income Loss Before Tax Portion Attributable To Parent OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent	27529000	USD
CY2021Q3	us-gaap	Finance Lease Liability Payments Due FinanceLeaseLiabilityPaymentsDue	13622000	USD
CY2021Q3	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	8836000	USD
CY2021Q3	us-gaap	Finance Lease Liability Undiscounted Excess Amount FinanceLeaseLiabilityUndiscountedExcessAmount	3626000	USD
CY2021Q3	us-gaap	Operating Lease Liability OperatingLeaseLiability	57144000	USD
CY2021Q3	us-gaap	Finance Lease Liability FinanceLeaseLiability	9996000	USD
CY2021Q3	bhlb	Financing Receivable Modifications Active Modified Loans FinancingReceivableModificationsActiveModifiedLoans	24	loan
CY2021Q3	bhlb	Financing Receivable Modifications Active Modified Loans Carrying Value FinancingReceivableModificationsActiveModifiedLoansCarryingValue	65000000	USD
CY2020Q4	bhlb	Financing Receivable Modifications Active Modified Loans FinancingReceivableModificationsActiveModifiedLoans	746	loan
CY2020Q4	bhlb	Financing Receivable Modifications Active Modified Loans Carrying Value FinancingReceivableModificationsActiveModifiedLoansCarryingValue	316000000	USD
CY2021Q3	us-gaap	Capital To Risk Weighted Assets CapitalToRiskWeightedAssets	0.177
CY2020Q4	us-gaap	Capital To Risk Weighted Assets CapitalToRiskWeightedAssets	0.161
CY2021Q3	bhlb	Common Equity Tier One Risk Based Capital To Risk Weighted Assets CommonEquityTierOneRiskBasedCapitalToRiskWeightedAssets	0.153
CY2020Q4	bhlb	Common Equity Tier One Risk Based Capital To Risk Weighted Assets CommonEquityTierOneRiskBasedCapitalToRiskWeightedAssets	0.138
CY2021Q3	us-gaap	Tier One Risk Based Capital To Risk Weighted Assets TierOneRiskBasedCapitalToRiskWeightedAssets	0.156
CY2020Q4	us-gaap	Tier One Risk Based Capital To Risk Weighted Assets TierOneRiskBasedCapitalToRiskWeightedAssets	0.141
CY2021Q3	us-gaap	Tier One Leverage Capital To Average Assets TierOneLeverageCapitalToAverageAssets	0.099
CY2020Q4	us-gaap	Tier One Leverage Capital To Average Assets TierOneLeverageCapitalToAverageAssets	0.094
CY2021Q3	us-gaap	Other Comprehensive Income Loss Before Tax Portion Attributable To Parent OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent	-10098000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Tax Portion Attributable To Parent1 OtherComprehensiveIncomeLossTaxPortionAttributableToParent1	-2575000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-7523000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Before Tax Portion Attributable To Parent OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent	-1085000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Tax Portion Attributable To Parent1 OtherComprehensiveIncomeLossTaxPortionAttributableToParent1	-272000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-813000	USD
	us-gaap	Other Comprehensive Income Loss Before Tax Portion Attributable To Parent OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent	-31718000	USD
	us-gaap	Other Comprehensive Income Loss Tax Portion Attributable To Parent1 OtherComprehensiveIncomeLossTaxPortionAttributableToParent1	-8096000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-23622000	USD
	us-gaap	Other Comprehensive Income Loss Tax Portion Attributable To Parent1 OtherComprehensiveIncomeLossTaxPortionAttributableToParent1	7096000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	20433000	USD
CY2021Q3	us-gaap	Oci Before Reclassifications Net Of Tax Attributable To Parent OciBeforeReclassificationsNetOfTaxAttributableToParent	-7523000	USD
CY2021Q3	us-gaap	Reclassification From Aoci Current Period Net Of Tax Attributable To Parent ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent	0	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-7523000	USD
CY2020Q3	us-gaap	Oci Before Reclassifications Net Of Tax Attributable To Parent OciBeforeReclassificationsNetOfTaxAttributableToParent	-809000	USD
CY2020Q3	us-gaap	Reclassification From Aoci Current Period Net Of Tax Attributable To Parent ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent	4000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-813000	USD
	us-gaap	Oci Before Reclassifications Net Of Tax Attributable To Parent OciBeforeReclassificationsNetOfTaxAttributableToParent	-23622000	USD
	us-gaap	Reclassification From Aoci Current Period Net Of Tax Attributable To Parent ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent	0	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-23622000	USD
	us-gaap	Oci Before Reclassifications Net Of Tax Attributable To Parent OciBeforeReclassificationsNetOfTaxAttributableToParent	20437000	USD
	us-gaap	Reclassification From Aoci Current Period Net Of Tax Attributable To Parent ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent	4000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	20433000	USD
CY2021Q3	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	63749000	USD
CY2020Q3	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	23043000	USD
	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	98416000	USD
	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	-532074000	USD
CY2021Q3	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	0	USD
CY2020Q3	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-1818000	USD
	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	0	USD
	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-15952000	USD
CY2021Q3	us-gaap	Net Income Loss NetIncomeLoss	63749000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	21225000	USD
	us-gaap	Net Income Loss NetIncomeLoss	98416000	USD
	us-gaap	Net Income Loss NetIncomeLoss	-548026000	USD
CY2021Q3	us-gaap	Weighted Average Number Of Shares Issued Basic WeightedAverageNumberOfSharesIssuedBasic	51903000	shares
CY2020Q3	us-gaap	Weighted Average Number Of Shares Issued Basic WeightedAverageNumberOfSharesIssuedBasic	51903000	shares
	us-gaap	Weighted Average Number Of Shares Issued Basic WeightedAverageNumberOfSharesIssuedBasic	51903000	shares
	us-gaap	Weighted Average Number Of Shares Issued Basic WeightedAverageNumberOfSharesIssuedBasic	51903000	shares
CY2021Q3	us-gaap	Weighted Average Number Of Shares Treasury Stock WeightedAverageNumberOfSharesTreasuryStock	2764000	shares
CY2020Q3	us-gaap	Weighted Average Number Of Shares Treasury Stock WeightedAverageNumberOfSharesTreasuryStock	1560000	shares
	us-gaap	Weighted Average Number Of Shares Treasury Stock WeightedAverageNumberOfSharesTreasuryStock	1519000	shares
	us-gaap	Weighted Average Number Of Shares Treasury Stock WeightedAverageNumberOfSharesTreasuryStock	1674000	shares
CY2021Q3	us-gaap	Weighted Average Number Of Shares Restricted Stock WeightedAverageNumberOfSharesRestrictedStock	744000	shares
CY2020Q3	us-gaap	Weighted Average Number Of Shares Restricted Stock WeightedAverageNumberOfSharesRestrictedStock	536000	shares
	us-gaap	Weighted Average Number Of Shares Restricted Stock WeightedAverageNumberOfSharesRestrictedStock	712000	shares
	us-gaap	Weighted Average Number Of Shares Restricted Stock WeightedAverageNumberOfSharesRestrictedStock	499000	shares
CY2021Q3	bhlb	Weighted Average Numberof Shares Outstanding Preferred Stock WeightedAverageNumberofSharesOutstandingPreferredStock	0	shares
CY2020Q3	bhlb	Weighted Average Numberof Shares Outstanding Preferred Stock WeightedAverageNumberofSharesOutstandingPreferredStock	522000	shares
	bhlb	Weighted Average Numberof Shares Outstanding Preferred Stock WeightedAverageNumberofSharesOutstandingPreferredStock	0	shares
	bhlb	Weighted Average Numberof Shares Outstanding Preferred Stock WeightedAverageNumberofSharesOutstandingPreferredStock	526000	shares
CY2021Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	48395000	shares
CY2020Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	50329000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	49672000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	50256000	shares
CY2021Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	48744000	shares
CY2020Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	50329000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	49963000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	50256000	shares
CY2021Q3	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	1.32
CY2020Q3	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.46
	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	1.98
	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	-10.58
CY2021Q3	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	0
CY2020Q3	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	-0.04
	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	0
	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	-0.32
CY2021Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.32
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.42
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.98
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-10.90
CY2021Q3	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	1.31
CY2020Q3	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.46
	bhlb	Investment Portfolio Number Of Securities InvestmentPortfolioNumberOfSecurities	1	security
	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	1.97
	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	-10.58
CY2021Q3	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerDilutedShare	0
CY2020Q3	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerDilutedShare	-0.04
	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerDilutedShare	0
	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerDilutedShare	-0.32
CY2021Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.31
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.42
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.97
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-10.90
CY2021Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	71368000	USD
CY2020Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	77055000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	221854000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	241073000	USD
CY2021Q3	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	-4000000	USD
CY2020Q3	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	1200000	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	2500000	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	65878000	USD
CY2021Q3	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	75368000	USD
CY2020Q3	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	75855000	USD
	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	219354000	USD
	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	175195000	USD

Files In Submission

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$BHLB
BERKSHIRE HILLS BANCORP INC Stock $bhlb

2021 Q3 Form 10-Q Financial Statement

#000110813421000025 Filed on November 09, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$BHLB BERKSHIRE HILLS BANCORP INC Stock $bhlb

2021 Q3 Form 10-Q Financial Statement

#000110813421000025 Filed on November 09, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$BHLB
BERKSHIRE HILLS BANCORP INC Stock $bhlb