XML 52 R44.htm IDEA: XBRL DOCUMENT
v3.20.1

Loans - Investment of Originated Loans Held-for-Investment by Loan Type and Credit Quality Indicator (Details) - USD ($) $ in Thousands | Mar. 31, 2020 | Dec. 31, 2019
--- | --- | ---
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | $ 3,098,760 | $ 2,987,067
Pass |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 3,083,462 | 2,968,346
Special Mention |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 1,699 | 2,850
Substandard |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 13,599 | 15,871
Real Estate | Multifamily | Less Than 35% LTV |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 247,893 | 233,251
Real Estate | Multifamily | Less Than 35% LTV | Pass |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 247,304 | 232,950
Real Estate | Multifamily | Less Than 35% LTV | Special Mention |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 291 | 0
Real Estate | Multifamily | Less Than 35% LTV | Substandard |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 298 | 301
Real Estate | Multifamily | Equal to or Greater than 35% LTV |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 2,056,494 | 1,966,483
Real Estate | Multifamily | Equal to or Greater than 35% LTV | Pass |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 2,051,039 | 1,960,984
Real Estate | Multifamily | Equal to or Greater than 35% LTV | Special Mention |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 292 | 296
Real Estate | Multifamily | Equal to or Greater than 35% LTV | Substandard |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 5,163 | 5,203
Real Estate | Commercial mortgage | Less Than 35% LTV |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 89,069 | 79,855
Real Estate | Commercial mortgage | Less Than 35% LTV | Pass |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 89,069 | 79,485
Real Estate | Commercial mortgage | Less Than 35% LTV | Special Mention |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 0 | 370
Real Estate | Commercial mortgage | Less Than 35% LTV | Substandard |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 0 | 0
Real Estate | Commercial mortgage | Equal to or Greater than 35% LTV |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 439,035 | 449,432
Real Estate | Commercial mortgage | Equal to or Greater than 35% LTV | Pass |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 432,711 | 440,065
Real Estate | Commercial mortgage | Equal to or Greater than 35% LTV | Special Mention |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 0 | 1,092
Real Estate | Commercial mortgage | Equal to or Greater than 35% LTV | Substandard |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 6,324 | 8,275
Real Estate | One-to-four family residential mortgage | Less Than 60% LTV |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 55,424 | 55,060
Real Estate | One-to-four family residential mortgage | Less Than 60% LTV | Pass |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 53,091 | 52,886
Real Estate | One-to-four family residential mortgage | Less Than 60% LTV | Special Mention |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 770 | 777
Real Estate | One-to-four family residential mortgage | Less Than 60% LTV | Substandard |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 1,563 | 1,397
Real Estate | One-to-four family residential mortgage | Equal to or Greater than 60% LTV |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 30,980 | 30,295
Real Estate | One-to-four family residential mortgage | Equal to or Greater than 60% LTV | Pass |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 30,953 | 29,967
Real Estate | One-to-four family residential mortgage | Equal to or Greater than 60% LTV | Special Mention |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 0 | 0
Real Estate | One-to-four family residential mortgage | Equal to or Greater than 60% LTV | Substandard |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 27 | 328
Real Estate | Construction and land |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 39,953 | 38,303
Real Estate | Construction and land | Pass |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 39,953 | 38,303
Real Estate | Construction and land | Special Mention |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 0 | 0
Real Estate | Construction and land | Substandard |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 0 | 0
Real Estate | Home equity and lines of credit |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 89,349 | 86,848
Real Estate | Home equity and lines of credit | Pass |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 89,082 | 86,547
Real Estate | Home equity and lines of credit | Special Mention |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 80 | 14
Real Estate | Home equity and lines of credit | Substandard |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 187 | 287
Commercial and Industrial |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 49,358 | 45,456
Commercial and Industrial | Pass |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 49,055 | 45,075
Commercial and Industrial | Special Mention |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 266 | 301
Commercial and Industrial | Substandard |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 37 | 80
Other |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 1,205 | 2,084
Other | Pass |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 1,205 | 2,084
Other | Special Mention |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | 0 | 0
Other | Substandard |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Loans receivable | $ 0 | $ 0

X
- 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_FinancingReceivableRecordedInvestmentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount, after allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 5 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919230-210447 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(3)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=118952595&loc=d3e4428-111522 + Details
Name: | us-gaap_NotesReceivableNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=us-gaap_PassMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=us-gaap_SpecialMentionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=us-gaap_SubstandardMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=nfbk_RealEstatePortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=srt_MultifamilyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LoanToValueAxis=nfbk_LessThan35LtvMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LoanToValueAxis=nfbk_EqualToOrGreaterThan35LtvMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=nfbk_OneToFourFamilyResidentialMortgageMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LoanToValueAxis=nfbk_LessThan60LtvMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LoanToValueAxis=nfbk_EqualToOrGreaterThan60LtvMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=nfbk_ConstructionAndLandLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_HomeEquityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=nfbk_CommercialAndIndustrialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=nfbk_OtherPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |