Employee benefit plan, catchup contributions, participant age, threshold.

No definition available.

Name:	bcbp_EmployeeBenefitPlanCatchupContributionsParticipantAgeThreshold
Namespace Prefix:	bcbp_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Employee benefit plan, death or disability, participant account, vesting percentage.

+ References

No definition available.

+ Details

Name:	bcbp_EmployeeBenefitPlanDeathOrDisabilityParticipantAccountVestingPercentage
Namespace Prefix:	bcbp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Employee benefit plan, employer contribution, eligibility, years of service, threshold.

+ References

No definition available.

+ Details

Name:	bcbp_EmployeeBenefitPlanEmployerContributionEligibilityYearsOfServiceThreshold
Namespace Prefix:	bcbp_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Employee benefit plan note receivable from participant account maximum borrowing amount description.

+ References

No definition available.

+ Details

Name:	bcbp_EmployeeBenefitPlanNoteReceivableFromParticipantAccountMaximumBorrowingAmountDescription
Namespace Prefix:	bcbp_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Employee benefit plan participant contribution pretax minimum annual compensation to total compensation percentage.

+ References

No definition available.

+ Details

Name:	bcbp_EmployeeBenefitPlanParticipantContributionPretaxMinimumAnnualCompensationToTotalCompensationPercentage
Namespace Prefix:	bcbp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Employee benefit plan, participant eligibility, days of service, threshold.

+ References

No definition available.

+ Details

Name:	bcbp_EmployeeBenefitPlanParticipantEligibilityDaysOfServiceThreshold
Namespace Prefix:	bcbp_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Employee benefit plan, participant eligibility, hours of service, threshold.

+ References

No definition available.

+ Details

Name:	bcbp_EmployeeBenefitPlanParticipantEligibilityHoursOfServiceThreshold
Namespace Prefix:	bcbp_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

Employee benefit plan, participant eligibility, participant age, threshold.

+ References

No definition available.

+ Details

Name:	bcbp_EmployeeBenefitPlanParticipantEligibilityParticipantAgeThreshold
Namespace Prefix:	bcbp_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Employee benefit plan participant loan period.

+ References

No definition available.

+ Details

Name:	bcbp_EmployeeBenefitPlanParticipantLoanPeriod
Namespace Prefix:	bcbp_
Data Type:	xbrli:decimalItemType
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/2009/role/commonPracticeRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-SubTopic 205
-Topic 962
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanDescriptionOfPlanLineItems
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of employer matching contribution on eligible participant contribution to employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanEmployerContributionMatchingPercentage
Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of participant compensation eligible for employer matching contribution for participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanEmployerContributionParticipantCompensationMatchedPercentage
Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of plan asset, in forfeited nonvested account, no longer allocated to participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 962
-SubTopic 325
-Name Accounting Standards Codification
-Section 55
-Paragraph 17
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478873/962-325-55-17

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (j)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

+ Details

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Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of minimum account balance that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) can borrow.

+ References

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanNoteReceivableFromParticipantAccountMinimumBorrowingAmount
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Percentage of eligible compensation contributed for participant automatically enrolled in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanParticipantContributionAutomaticDeferralRate
Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of maximum pretax annual compensation that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)), is permitted to contribute to total pretax annual compensation.

+ References

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanParticipantContributionPretaxMaximumAnnualCompensationToTotalCompensationPercentage
Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Interest rate on participant loan in schedule of asset held for investment of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6A-05(a)(Schedule I))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477804/962-205-S99-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Employee Retirement Income Security Act of 1974
-Number 2520
-Section 103
-Subsection 10
-Paragraph b
-Subparagraph (1)(i)(D)
-Publisher DOL-EBSA

+ Details

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Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	dei_LegalEntityAxis=bcbp_EBP001Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=bcbp_NotesReceivablesFromParticipantMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	bcbp_MatchingPercentageAxis=bcbp_UntilTwoPercentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	bcbp_MatchingPercentageAxis=bcbp_TwoToFourPercentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	bcbp_LoanTypeAxis=bcbp_PrincipalResidentialLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: