Loans Receivable and Allowance for Loan Losses (Inclusions in the Consolidated Statements of Financial Condition) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Loans Receivable and Allowance for Loan Losses [Abstract]
Acquired Loans, Unpaid principal balance	$ 216,741	$ 274,205
Acquired loans, Recorded investment	$ 209,150bcbp_AcquiredLoansRecordedInvestment	$ 270,328bcbp_AcquiredLoansRecordedInvestment

Value as of the balance sheet date of the unpaid principal balances of acquired loans.

No definition available.

Name:	bcbp_AcquiredLoansUnpaidPrincipalBalance
Namespace Prefix:	bcbp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant