Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 5
-SubTopic 10
-Topic 815
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480463/815-10-45-5

+ Details

Name:	us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Average remaining period until maturity of the derivative contract, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeAverageRemainingMaturity1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480237/815-40-50-5

+ Details

Name:	us-gaap_DerivativeLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480434/815-10-50-1B

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1A
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480434/815-10-50-1A

+ Details

Name:	us-gaap_DerivativeNotionalAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of asset hedged in fair value hedging relationship.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 181
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480401/815-10-55-181

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4EE
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480434/815-10-50-4EE

+ Details

Name:	us-gaap_HedgedAssetFairValueHedge
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of cumulative increase (decrease) in fair value of hedged asset in fair value hedge, attributable to hedged risk.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 181
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480401/815-10-55-181

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4EE
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480434/815-10-50-4EE

+ Details

Name:	us-gaap_HedgedAssetFairValueHedgeCumulativeIncreaseDecrease
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_HedgingDesignationAxis=us-gaap_DesignatedAsHedgingInstrumentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_CashFlowHedgingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=bhb_InterestRateSwapOnWholesaleFundingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=bhb_InterestRateSwapOnVariableRateLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_FairValueHedgingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateSwapMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=bhb_EconomicHedgingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForeignExchangeForwardMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=bhb_CustomerLoanDerivativeLiabilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=bhb_MnaCounterpartyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=bhb_RpaCounterpartyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=bhb_CustomerCounterpartyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_HedgingDesignationAxis=us-gaap_NondesignatedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateLockCommitmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

DERIVATIVE FINANCIAL INSTRUMENTS AND HEDGING ACTIVITIES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2020	Apr. 30, 2020	Nov. 30, 2019
Derivative [Line Items]
Notional Amount	$ 824,393	$ 774,019
Fair Value Asset (Liability)	3,231	4,811
Designated as hedging instrument \| Cash flow hedges
Derivative [Line Items]
Notional Amount	125,000	125,000
Fair Value Asset (Liability)	(656)	37
Designated as hedging instrument \| Cash flow hedges \| Interest rate swap on wholesale funding
Derivative [Line Items]
Notional Amount	$ 75,000	$ 75,000		$ 25,000	$ 50,000
Weighted Average Maturity (in years)	1 year	2 years
Fair Value Asset (Liability)	$ 2,803	$ 4,978
Designated as hedging instrument \| Cash flow hedges \| Interest rate swap on variable rate loans
Derivative [Line Items]
Notional Amount	$ 50,000	$ 50,000
Weighted Average Maturity (in years)	2 years 2 months 12 days	3 years 2 months 12 days
Fair Value Asset (Liability)	$ (3,459)	$ (4,941)
Designated as hedging instrument \| Fair Value Hedging
Derivative [Line Items]
Notional Amount	37,190	37,190
Fair Value Asset (Liability)	3,844	4,774
Designated as hedging instrument \| Fair Value Hedging \| Interest rate swap on deposits
Derivative [Line Items]
Notional Amount	$ 37,190	$ 37,190	$ 37,200
Weighted Average Maturity (in years)	5 years 7 months 6 days	6 years 7 months 6 days
Fair Value Asset (Liability)	$ 3,844	$ 4,774
Carrying Amount of Hedged Assets	32,680	30,045
Cumulative Amount of Fair Value Hedging Adjustment in Carrying Amount	(4,510)	(7,145)
Designated as hedging instrument \| Economic hedges
Derivative [Line Items]
Notional Amount	659,050	611,829
Fair Value Asset (Liability)	(20)
Designated as hedging instrument \| Economic hedges \| Forward sale commitments
Derivative [Line Items]
Notional Amount	5,000
Fair Value Asset (Liability)	(20)
Designated as hedging instrument \| Economic hedges \| Customer loan derivative liability \| MNA counterparty
Derivative [Line Items]
Notional Amount	$ 184,826	$ 191,987
Weighted Average Maturity (in years)	5 years	5 years 9 months 18 days
Fair Value Asset (Liability)	$ (14,842)	$ (20,287)
Designated as hedging instrument \| Economic hedges \| Customer loan derivative liability \| RPA counterparty
Derivative [Line Items]
Notional Amount	$ 142,199	$ 113,928
Weighted Average Maturity (in years)	4 years 10 months 24 days	6 years
Fair Value Asset (Liability)	$ (286)
Designated as hedging instrument \| Economic hedges \| Customer loan derivative liability \| Customer
Derivative [Line Items]
Notional Amount	$ 327,025	$ 305,914
Weighted Average Maturity (in years)	4 years 10 months 24 days	5 years 10 months 24 days
Fair Value Asset (Liability)	$ 15,128	$ 20,287
Not designated as hedging instrument
Derivative [Line Items]
Notional Amount	3,153
Fair Value Asset (Liability)	63
Not designated as hedging instrument \| Interest Rate Lock Commitment
Derivative [Line Items]
Notional Amount	$ 3,153
Weighted Average Maturity (in years)	1 month 6 days
Fair Value Asset (Liability)	$ 63