XML 51 R56.htm IDEA: XBRL DOCUMENT v2.4.1.9
Loans (Summary Of Impaired Loans) (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Financing Receivable, Impaired [Line Items]    
Recorded investment $ 33,419us-gaap_ImpairedFinancingReceivableRecordedInvestment $ 38,337us-gaap_ImpairedFinancingReceivableRecordedInvestment
Unpaid Principal Balance 36,941us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance 42,441us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
Related Allowance (2,755)us-gaap_ImpairedFinancingReceivableRelatedAllowance (2,632)us-gaap_ImpairedFinancingReceivableRelatedAllowance
Special Mention | Less Than 60% LTV    
Financing Receivable, Impaired [Line Items]    
Recorded Investment With No Related Allowance Recorded 138us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
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= nfbk_LessThan60LtvMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember		  
Unpaid Principal Balance With No Related Allowance Recorded 138us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
/ nfbk_FinanceReceivablesAgingAxis
= nfbk_LessThan60LtvMember
/ us-gaap_InternalCreditAssessmentAxis
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Commercial mortgage    
Financing Receivable, Impaired [Line Items]    
Recorded investment 29,224us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember		 32,193us-gaap_ImpairedFinancingReceivableRecordedInvestment
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Unpaid Principal Balance 32,152us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember		 35,240us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
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= us-gaap_CommercialPortfolioSegmentMember
Related Allowance (2,361)us-gaap_ImpairedFinancingReceivableRelatedAllowance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember		 (2,385)us-gaap_ImpairedFinancingReceivableRelatedAllowance
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= us-gaap_CommercialPortfolioSegmentMember
Commercial mortgage | Pass | Less Than 35% LTV    
Financing Receivable, Impaired [Line Items]    
Recorded Investment With No Related Allowance Recorded   3,405us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ nfbk_FinanceReceivablesAgingAxis
= nfbk_LessThan35LtvMember
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= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
Unpaid Principal Balance With No Related Allowance Recorded   3,542us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
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= nfbk_LessThan35LtvMember
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/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
Commercial mortgage | Pass | Greater Than or Equal to 35% LTV    
Financing Receivable, Impaired [Line Items]    
Recorded Investment With No Related Allowance Recorded 3,311us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ nfbk_FinanceReceivablesAgingAxis
= nfbk_EqualToOrGreaterThanThirtyFivePercentageLtvMember
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= us-gaap_CommercialPortfolioSegmentMember
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= us-gaap_PassMember		 19,689us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
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/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
Unpaid Principal Balance With No Related Allowance Recorded 3,448us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
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/ us-gaap_InternalCreditAssessmentAxis
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Commercial mortgage | Special Mention | Greater Than or Equal to 35% LTV    
Financing Receivable, Impaired [Line Items]    
Recorded Investment With a Related Allowance Recorded   2,289us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
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= us-gaap_SpecialMentionMember
Unpaid Principal Balance With a Related Allowance Recorded   2,672us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
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/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
Related Allowance With a Related Allowance Recorded   (52)nfbk_ImpairedFinancingReceivableRelatedAllowanceWithAllowanceRecorded
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Commercial mortgage | Substandard | Less Than 35% LTV    
Financing Receivable, Impaired [Line Items]    
Recorded Investment With No Related Allowance Recorded   0us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
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Unpaid Principal Balance With No Related Allowance Recorded   707us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
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= nfbk_LessThan35LtvMember
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Commercial mortgage | Substandard | Greater Than or Equal to 35% LTV    
Financing Receivable, Impaired [Line Items]    
Recorded Investment With No Related Allowance Recorded 12,880us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
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Recorded Investment With a Related Allowance Recorded 13,033us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
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Unpaid Principal Balance With No Related Allowance Recorded 14,339us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
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Unpaid Principal Balance With a Related Allowance Recorded 14,365us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
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Related Allowance With a Related Allowance Recorded (2,361)nfbk_ImpairedFinancingReceivableRelatedAllowanceWithAllowanceRecorded
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One-to-four family residential mortgage    
Financing Receivable, Impaired [Line Items]    
Recorded investment 1,072us-gaap_ImpairedFinancingReceivableRecordedInvestment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nfbk_OneToFourFamilyResidentialMortgageMember		 1,116us-gaap_ImpairedFinancingReceivableRecordedInvestment
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Unpaid Principal Balance 1,072us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nfbk_OneToFourFamilyResidentialMortgageMember		 1,116us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
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Related Allowance (57)us-gaap_ImpairedFinancingReceivableRelatedAllowance
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One-to-four family residential mortgage | Special Mention | Less Than 60% LTV    
Financing Receivable, Impaired [Line Items]    
Recorded Investment With No Related Allowance Recorded   507us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
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= nfbk_LessThan60LtvMember
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Unpaid Principal Balance With No Related Allowance Recorded   507us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
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One-to-four family residential mortgage | Special Mention | Greater than or Equal to 60% LTV    
Financing Receivable, Impaired [Line Items]    
Recorded Investment With a Related Allowance Recorded 319us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
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= nfbk_EqualToOrGreaterThan60LtvMember
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Unpaid Principal Balance With a Related Allowance Recorded 319us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
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Related Allowance With a Related Allowance Recorded (4)nfbk_ImpairedFinancingReceivableRelatedAllowanceWithAllowanceRecorded
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One-to-four family residential mortgage | Substandard | Less Than 60% LTV    
Financing Receivable, Impaired [Line Items]    
Recorded Investment With No Related Allowance Recorded 262us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
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Unpaid Principal Balance With No Related Allowance Recorded 262us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
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One-to-four family residential mortgage | Substandard | Greater than or Equal to 60% LTV    
Financing Receivable, Impaired [Line Items]    
Recorded Investment With a Related Allowance Recorded 353us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
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Unpaid Principal Balance With a Related Allowance Recorded 353us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
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Related Allowance With a Related Allowance Recorded (53)nfbk_ImpairedFinancingReceivableRelatedAllowanceWithAllowanceRecorded
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Construction and land    
Financing Receivable, Impaired [Line Items]    
Recorded investment   108us-gaap_ImpairedFinancingReceivableRecordedInvestment
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= nfbk_ConstructionAndLandMember
Unpaid Principal Balance   91us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
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Related Allowance   0us-gaap_ImpairedFinancingReceivableRelatedAllowance
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Construction and land | Substandard    
Financing Receivable, Impaired [Line Items]    
Recorded Investment With No Related Allowance Recorded   108us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
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Unpaid Principal Balance With No Related Allowance Recorded   91us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
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Multifamily    
Financing Receivable, Impaired [Line Items]    
Recorded investment 1,990us-gaap_ImpairedFinancingReceivableRecordedInvestment
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Unpaid Principal Balance 2,461us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
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= nfbk_MultiFamilyMember		 2,545us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
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Related Allowance (215)us-gaap_ImpairedFinancingReceivableRelatedAllowance
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Multifamily | Pass | Greater Than or Equal to 35% LTV    
Financing Receivable, Impaired [Line Items]    
Recorded Investment With No Related Allowance Recorded 86us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
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Unpaid Principal Balance With No Related Allowance Recorded 557us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
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Multifamily | Substandard | Less Than 35% LTV    
Financing Receivable, Impaired [Line Items]    
Recorded Investment With No Related Allowance Recorded   593us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
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Unpaid Principal Balance With No Related Allowance Recorded   1,064us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
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Multifamily | Substandard | Greater Than or Equal to 35% LTV    
Financing Receivable, Impaired [Line Items]    
Recorded Investment With No Related Allowance Recorded 477us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
/ nfbk_FinanceReceivablesAgingAxis
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Recorded Investment With a Related Allowance Recorded 1,427us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
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Unpaid Principal Balance With No Related Allowance Recorded 477us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
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/ us-gaap_InternalCreditAssessmentAxis
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Unpaid Principal Balance With a Related Allowance Recorded 1,427us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
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Home equity and lines of credit    
Financing Receivable, Impaired [Line Items]    
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Home equity and lines of credit | Special Mention    
Financing Receivable, Impaired [Line Items]    
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Home equity and lines of credit | Substandard    
Financing Receivable, Impaired [Line Items]    
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Commercial and industrial loans    
Financing Receivable, Impaired [Line Items]    
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Commercial and industrial loans | Special Mention    
Financing Receivable, Impaired [Line Items]    
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Commercial and industrial loans | Substandard    
Financing Receivable, Impaired [Line Items]    
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