LOANS - Recorded Investment and Number of Modifications (Details) $ in Thousands	3 Months Ended
Mar. 31, 2017 USD ($) modification	Mar. 31, 2016 USD ($) modification
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Modifications \| modification	4,000	4,000
Pre-Modification Outstanding Recorded Investment	$ 693	$ 425
Post-Modification Outstanding Recorded Investment	$ 691	$ 419
Residential Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Modifications \| modification	2,000
Pre-Modification Outstanding Recorded Investment	$ 575
Post-Modification Outstanding Recorded Investment	$ 574
Commercial real estate other \| Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Modifications \| modification		2,000
Pre-Modification Outstanding Recorded Investment		$ 395
Post-Modification Outstanding Recorded Investment		$ 394
Commercial other \| Commercial and Industrial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Modifications \| modification	1,000
Pre-Modification Outstanding Recorded Investment	$ 80
Post-Modification Outstanding Recorded Investment	$ 80
Agricultural and other loans to farmers \| Commercial and Industrial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Modifications \| modification		2,000
Pre-Modification Outstanding Recorded Investment		$ 30
Post-Modification Outstanding Recorded Investment		$ 25
Consumer other \| Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Modifications \| modification	1,000
Pre-Modification Outstanding Recorded Investment	$ 38
Post-Modification Outstanding Recorded Investment	$ 37

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.

No definition available.

+ Details

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

- Definition

Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953676-111524

+ Details

Name:	us-gaap_FinancingReceivableModificationsNumberOfContracts2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Post-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

+ Details

Name:	us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Pre-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

+ Details

Name:	us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=bhb_OtherCommercialRealEstateLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=bhb_CommercialInstallmentLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=bhb_CommercialandIndustrialLoansPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=bhb_AgricultureAndOtherLoansToFarmersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=bhb_OtherConsumerLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: