Debt Instrument, Interest Rate Term

No definition available.

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

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 55
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482949/835-30-55-8

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+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The average effective interest rate during the reporting period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(a)(1))
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-URI https://asc.fasb.org/1943274/2147482925/835-30-45-2

+ Details

Name:	us-gaap_DebtInstrumentInterestRateDuringPeriod
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Period of time between issuance and maturity of debt instrument, 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_DebtInstrumentTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
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-Publisher FASB
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+ Details

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

- Definition

Amount that would be paid, determined under the conditions specified in the contract, if the holder of the share has the right to redeem the shares.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 480
-SubTopic 10
-Section 50
-Paragraph 2
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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Stated interest rate of the subordinated debt.

+ References

No definition available.

+ Details

Name:	us-gaap_SubordinatedBorrowingInterestRate
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
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

No definition available.

+ Details

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

- Details

Name:	us-gaap_SubordinatedBorrowingAxis=bcbp_FixedToFloatingRateSubordinatedDebenturesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubordinatedBorrowingAxis=bcbp_TrustPreferredJuniorSubordinatedDebentureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Subordinated Debt (Narrative) (Details) - USD ($)		9 Months Ended
Subordinated Debt (Narrative) (Details) - USD ($)	Aug. 29, 2024	Sep. 30, 2025	Dec. 31, 2024	Jul. 30, 2018
Fixed To Floating Rate Subordinated Debentures [Member]
Subordinated Borrowing [Line Items]
Face amount	$ 40,000,000			$ 33,500,000
Notes term	10 years
Debt instrument, interest rate during period		6.935%
Variable interest rate spread	5.82%	0.26161%
Deferred finance costs			$ 975,000
Fixed To Floating Rate Subordinated Debentures [Member] \| First Five Years [Member]
Subordinated Borrowing [Line Items]
Notes term	5 years
Interest rate	9.25%
Interest rate term		5 years
Trust Preferred Junior Subordinated Debenture [Member]
Subordinated Borrowing [Line Items]
Variable interest rate spread		2.65%
Trust preferred securities		$ 4,100,000