Allowance for Credit Losses - Schedule of Aging and Non-Accrual Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	$ 5,404,667	$ 5,387,676
90 Days Past Due or More & Still Accruing	4,200	3,623
Non-accrual loans	74,359	70,613
Total Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	160,577	104,115
30 - 59 Days Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	46,406	23,590
60 - 89 Days Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	45,566	13,512
90 Days or More Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	68,605	67,013
Current Loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	5,244,090	5,283,561
Commercial real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	2,806,846	2,769,287
90 Days Past Due or More & Still Accruing	369	677
Non-accrual loans	41,896	37,318
Commercial real estate \| Total Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	90,540	44,102
Commercial real estate \| 30 - 59 Days Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	16,220	4,535
Commercial real estate \| 60 - 89 Days Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	34,578	1,676
Commercial real estate \| 90 Days or More Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	39,742	37,891
Commercial real estate \| Current Loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	2,716,306	2,725,185
Owner-occupied commercial real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	579,365	593,120
90 Days Past Due or More & Still Accruing	183	177
Non-accrual loans	6,842	7,800
Owner-occupied commercial real estate \| Total Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	13,485	8,652
Owner-occupied commercial real estate \| 30 - 59 Days Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	6,048	1,251
Owner-occupied commercial real estate \| 60 - 89 Days Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	1,278	1,091
Owner-occupied commercial real estate \| 90 Days or More Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	6,159	6,310
Owner-occupied commercial real estate \| Current Loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	565,880	584,468
Acquisition, construction & development
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	352,686	386,870
90 Days Past Due or More & Still Accruing	224	559
Non-accrual loans	12,541	12,793
Acquisition, construction & development \| Total Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	17,569	14,520
Acquisition, construction & development \| 30 - 59 Days Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	329	578
Acquisition, construction & development \| 60 - 89 Days Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	4,539	699
Acquisition, construction & development \| 90 Days or More Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	12,701	13,243
Acquisition, construction & development \| Current Loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	335,117	372,350
Commercial & industrial
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	504,229	461,921
90 Days Past Due or More & Still Accruing	1,715	512
Non-accrual loans	5,617	5,512
Commercial & industrial \| Total Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	9,981	9,991
Commercial & industrial \| 30 - 59 Days Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	2,621	2,008
Commercial & industrial \| 60 - 89 Days Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	347	2,354
Commercial & industrial \| 90 Days or More Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	7,013	5,629
Commercial & industrial \| Current Loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	494,248	451,930
Single family residential (1-4 units)
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	1,128,740	1,127,684
90 Days Past Due or More & Still Accruing	1,699	1,694
Non-accrual loans	7,021	6,802
Single family residential (1-4 units) \| Total Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	27,217	25,958
Single family residential (1-4 units) \| 30 - 59 Days Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	19,874	14,823
Single family residential (1-4 units) \| 60 - 89 Days Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	4,775	7,541
Single family residential (1-4 units) \| 90 Days or More Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	2,568	3,594
Single family residential (1-4 units) \| Current Loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	1,101,523	1,101,726
Consumer non-real estate and other
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	32,801	48,794
90 Days Past Due or More & Still Accruing	10	4
Non-accrual loans	442	388
Consumer non-real estate and other \| Total Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	1,785	892
Consumer non-real estate and other \| 30 - 59 Days Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	1,314	395
Consumer non-real estate and other \| 60 - 89 Days Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	49	151
Consumer non-real estate and other \| 90 Days or More Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	422	346
Consumer non-real estate and other \| Current Loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans	$ 31,016	$ 47,902

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.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph c
-Publisher SEC

+ Details

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

- Definition

Amortized cost excluding accrued interest, of financing receivable 90 days or more past due and still accruing. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-16

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterest90DaysOrMorePastDueStillAccruing
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amortized cost excluding accrued interest, before allowance for credit loss, of financing receivable. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479344/326-20-45-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-3B

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-5

+ Details

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

- Definition

Amortized cost of financing receivable on nonaccrual status. Excludes net investment in lease.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-7

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph a
-Subparagraph (3)
-Publisher SEC

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph a
-Subparagraph (2)
-Publisher SEC

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-16

+ Details

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

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancialAssetPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivables30To59DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivables60To89DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancialAssetNotPastDueMember
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_FinancingReceivablePortfolioSegmentAxis=bhrb_OwnerOccupiedCommercialRealEstateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

- Details

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