$NFBK
Northfield Bancorp, Inc. Stock $nfbk

$nfbk Overview Financials Valuation SEC Filings Company Website

2021 Q4 Form 10-Q Financial Statement

#000149322521000115 Filed on November 09, 2021

Income Statement

Concept	2021 Q4	2021 Q3	2020 Q3
Revenue	$41.85M	$42.15M	$41.46M
YoY Change	-2.78%	1.66%	-3.24%
Cost Of Revenue
YoY Change
Gross Profit
YoY Change
Gross Profit Margin
Selling, General & Admin
YoY Change
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$1.020M	$1.020M	$1.050M
YoY Change	-23.88%	-2.86%	25.0%
% of Gross Profit
Operating Expenses
YoY Change
Operating Profit
YoY Change
Interest Expense	$3.480M	$3.729M	$8.849M
YoY Change	-42.08%	-57.86%	-36.91%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	$21.91M	$22.16M	$11.68M
YoY Change	25.36%	89.76%	-35.07%
Income Tax	$5.810M	$6.078M	$3.095M
% Of Pretax Income	26.51%	27.43%	26.51%
Net Earnings	$16.10M	$16.08M	$8.582M
YoY Change	23.28%	87.37%	-34.68%
Net Earnings / Revenue	38.48%	38.15%	20.7%
Basic Earnings Per Share	$0.34	$0.33	$0.17
Diluted Earnings Per Share	$0.34	$0.33	$0.17
COMMON SHARES
Basic Shares Outstanding	49.62M shares	48.10M shares	50.71M shares
Diluted Shares Outstanding		48.49M shares	50.72M shares

Balance Sheet

Concept	2021 Q4	2021 Q3	2020 Q3
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$91.07M	$173.7M	$350.8M
Short-Term Investments
Other Short-Term Assets
YoY Change
Inventory
Prepaid Expenses
Receivables
Other Receivables
Total Short-Term Assets
YoY Change
LONG-TERM ASSETS
Property, Plant & Equipment	$25.94M	$26.56M	$27.98M
YoY Change	-7.99%	-5.07%	7.75%
Goodwill	$41.01M	$41.01M	$41.59M
YoY Change	-0.75%	-1.4%	8.29%
Intangibles
YoY Change
Long-Term Investments
YoY Change
Other Assets
YoY Change
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets	$5.431B	$5.398B	$5.589B
YoY Change	-1.52%	-3.41%	16.23%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$24.90M	$23.50M	$17.30M
YoY Change	26.4%	35.84%	-7.98%
Accrued Expenses	$74.70M	$72.20M	$76.00M
YoY Change	3.03%	-5.0%	6.74%
Deferred Revenue
YoY Change
Short-Term Debt	$50.00M	$50.00M	$75.00M
YoY Change	-33.33%	-33.33%	0.0%
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$99.60M	$95.70M	$93.30M
YoY Change	8.03%	2.57%	3.67%
LONG-TERM LIABILITIES
Long-Term Debt	$371.8M	$371.8M	$541.9M
YoY Change	-28.06%	-31.39%	-12.06%
Other Long-Term Liabilities
YoY Change
Total Long-Term Liabilities	$371.8M	$371.8M	$541.9M
YoY Change	-28.06%	-31.39%	-12.06%
TOTAL LIABILITIES
Total Short-Term Liabilities	$99.60M	$95.70M	$93.30M
Total Long-Term Liabilities	$371.8M	$371.8M	$541.9M
Total Liabilities	$4.691B	$4.659B	$4.831B
YoY Change	-1.47%	-3.57%	17.31%
SHAREHOLDERS EQUITY
Retained Earnings	$381.4M	$371.4M	$330.6M
YoY Change	12.8%	12.34%	4.1%
Common Stock	$648.0K	$648.0K	$648.0K
YoY Change	0.0%	0.0%	6.4%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$217.1M	$212.0M	$159.6M
YoY Change	27.79%	32.83%	-0.91%
Treasury Stock Shares	15.50M shares	15.22M shares	11.67M shares
Shareholders Equity	$739.9M	$739.2M	$757.4M
YoY Change
Total Liabilities & Shareholders Equity	$5.431B	$5.398B	$5.589B
YoY Change	-1.52%	-3.41%	16.23%

Cashflow Statement

Concept	2021 Q4	2021 Q3	2020 Q3
OPERATING ACTIVITIES
Net Income	$16.10M	$16.08M	$8.582M
YoY Change	23.28%	87.37%	-34.68%
Depreciation, Depletion And Amortization	$1.020M	$1.020M	$1.050M
YoY Change	-23.88%	-2.86%	25.0%
Cash From Operating Activities	$21.36M	$18.41M	$3.300M
YoY Change	-17.18%	457.88%	-81.52%
INVESTING ACTIVITIES
Capital Expenditures	-$350.0K	-$260.0K	-$360.0K
YoY Change	-76.35%	-27.78%	-65.38%
Acquisitions
YoY Change
Other Investing Activities	-$121.6M	$6.490M	$99.58M
YoY Change	-40.49%	-93.48%	-625.49%
Cash From Investing Activities	-$121.9M	$6.210M	$99.24M
YoY Change	-40.76%	-93.74%	-596.45%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	17.97M	-44.13M	137.4M
YoY Change	-121.59%	-132.12%	452.29%
NET CHANGE
Cash From Operating Activities	21.36M	18.41M	3.300M
Cash From Investing Activities	-121.9M	6.210M	99.24M
Cash From Financing Activities	17.97M	-44.13M	137.4M
Net Change In Cash	-82.61M	-19.51M	240.0M
YoY Change	-68.63%	-108.13%	954.73%
FREE CASH FLOW
Cash From Operating Activities	$21.36M	$18.41M	$3.300M
Capital Expenditures	-$350.0K	-$260.0K	-$360.0K
Free Cash Flow	$21.71M	$18.67M	$3.660M
YoY Change	-20.39%	410.11%	-80.63%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
	dei	Entity Central Index Key EntityCentralIndexKey	0001493225
	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2021
	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	Q3
	dei	Amendment Flag AmendmentFlag	false
CY2020	us-gaap	Accounting Standards Update Extensible List AccountingStandardsUpdateExtensibleList	http://fasb.org/us-gaap/2021-01-31#AccountingStandardsUpdate201613Member
	dei	Document Type DocumentType	10-Q
	dei	Entity File Number EntityFileNumber	001-35791
	dei	Document Quarterly Report DocumentQuarterlyReport	true
	dei	Document Period End Date DocumentPeriodEndDate	2021-09-30
	dei	Document Transition Report DocumentTransitionReport	false
	dei	Entity Registrant Name EntityRegistrantName	Northfield Bancorp, Inc.
	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	DE
	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	80-0882592
	dei	Entity Address Address Line1 EntityAddressAddressLine1	581 Main Street,
	dei	Entity Address City Or Town EntityAddressCityOrTown	Woodbridge,
	dei	Entity Address State Or Province EntityAddressStateOrProvince	NJ
	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	07095
	dei	City Area Code CityAreaCode	732
	dei	Local Phone Number LocalPhoneNumber	499-7200
	dei	Security12b Title Security12bTitle	Common stock, par value $0.01 per share
	dei	Trading Symbol TradingSymbol	NFBK
	dei	Security Exchange Name SecurityExchangeName	NASDAQ
	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
	dei	Entity Filer Category EntityFilerCategory	Accelerated Filer
	dei	Entity Small Business EntitySmallBusiness	false
	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
	dei	Entity Shell Company EntityShellCompany	false
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	us-gaap	Labor And Related Expense LaborAndRelatedExpense	31039000	USD
	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	665000	USD
CY2021Q3	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	101000	USD
CY2020Q3	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	311000	USD
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	246000	USD
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	772000	USD
CY2021Q3	us-gaap	Noninterest Income NoninterestIncome	2628000	USD
CY2020Q3	us-gaap	Noninterest Income NoninterestIncome	3022000	USD
	us-gaap	Noninterest Income NoninterestIncome	10180000	USD
	us-gaap	Noninterest Income NoninterestIncome	7369000	USD
CY2021Q3	us-gaap	Labor And Related Expense LaborAndRelatedExpense	10334000	USD
CY2020Q3	us-gaap	Labor And Related Expense LaborAndRelatedExpense	13306000	USD
	us-gaap	Labor And Related Expense LaborAndRelatedExpense	31672000	USD
CY2021Q3	us-gaap	Occupancy Net OccupancyNet	3425000	USD
CY2020Q3	us-gaap	Occupancy Net OccupancyNet	3540000	USD
	us-gaap	Occupancy Net OccupancyNet	10626000	USD
	us-gaap	Occupancy Net OccupancyNet	9618000	USD
CY2021Q3	us-gaap	Equipment Expense EquipmentExpense	431000	USD
CY2020Q3	us-gaap	Equipment Expense EquipmentExpense	425000	USD
	us-gaap	Equipment Expense EquipmentExpense	1310000	USD
	us-gaap	Equipment Expense EquipmentExpense	1107000	USD
CY2021Q3	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	1538000	USD
CY2020Q3	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	3058000	USD
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	4968000	USD
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	6130000	USD
CY2021Q3	us-gaap	Professional Fees ProfessionalFees	826000	USD
CY2020Q3	us-gaap	Professional Fees ProfessionalFees	1216000	USD
	us-gaap	Professional Fees ProfessionalFees	2564000	USD
	us-gaap	Professional Fees ProfessionalFees	3370000	USD
CY2021Q3	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	576000	USD
CY2020Q3	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	424000	USD
	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	1725000	USD
	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	1585000	USD
CY2021Q3	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	336000	USD
CY2020Q3	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	360000	USD
	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	1057000	USD
	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	576000	USD
CY2021Q3	us-gaap	Other Noninterest Expense OtherNoninterestExpense	1569000	USD
CY2020Q3	us-gaap	Other Noninterest Expense OtherNoninterestExpense	1459000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	4547000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	3901000	USD
CY2021Q3	us-gaap	Noninterest Expense NoninterestExpense	19035000	USD
CY2020Q3	us-gaap	Noninterest Expense NoninterestExpense	23788000	USD
	us-gaap	Noninterest Expense NoninterestExpense	58469000	USD
	us-gaap	Noninterest Expense NoninterestExpense	57326000	USD
CY2021Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	22158000	USD
CY2020Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	11677000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	75214000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	32545000	USD
CY2021Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	6078000	USD
CY2020Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	3095000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	20663000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	8619000	USD
CY2021Q3	us-gaap	Net Income Loss NetIncomeLoss	16080000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	8582000	USD
	us-gaap	Net Income Loss NetIncomeLoss	54551000	USD
	us-gaap	Net Income Loss NetIncomeLoss	23926000	USD
CY2021Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.33
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.17
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.12
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.50
CY2021Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.33
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.17
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.11
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.50
CY2021Q3	us-gaap	Net Income Loss NetIncomeLoss	16080000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	8582000	USD
	us-gaap	Net Income Loss NetIncomeLoss	54551000	USD
CY2020Q3	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	346000	USD
	us-gaap	Net Income Loss NetIncomeLoss	23926000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-3550000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-328000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-6700000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	13585000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	370000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	45000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	976000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	105000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	-3920000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	-373000	USD
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	-7676000	USD
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	13480000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-995000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-92000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-1876000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	3802000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	103000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	13000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	273000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	30000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-2822000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-268000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-5527000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	9708000	USD
CY2021Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	13258000	USD
CY2020Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	8314000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	49024000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	33634000	USD
CY2020Q2	us-gaap	Stockholders Equity StockholdersEquity	712576000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	8582000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-268000	USD
CY2020Q3	us-gaap	Amortization Of Esop Award AmortizationOfESOPAward	301000	USD
CY2020Q3	us-gaap	Restricted Stock Award Forfeitures RestrictedStockAwardForfeitures	0	USD
CY2020Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.11
CY2020Q3	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.11
CY2020Q3	us-gaap	Dividends Common Stock DividendsCommonStock	5586000	USD
CY2020Q3	us-gaap	Stock Issued During Period Value Acquisitions StockIssuedDuringPeriodValueAcquisitions	41447000	USD
CY2020Q3	us-gaap	Stockholders Equity StockholdersEquity	757398000	USD
CY2021Q2	us-gaap	Stockholders Equity StockholdersEquity	753210000	USD
CY2021Q3	us-gaap	Net Income Loss NetIncomeLoss	16080000	USD
CY2021Q3	us-gaap	Net Income Loss NetIncomeLoss	16080000	USD
CY2021Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-2822000	USD
CY2021Q3	us-gaap	Amortization Of Esop Award AmortizationOfESOPAward	495000	USD
CY2021Q3	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	246000	USD
CY2021Q3	us-gaap	Restricted Stock Award Forfeitures RestrictedStockAwardForfeitures	0	USD
CY2021Q3	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	447000	USD
CY2021Q3	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.13
CY2021Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.13
CY2021Q3	us-gaap	Dividends Common Stock DividendsCommonStock	6310000	USD
CY2021Q3	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	16.63
CY2021Q3	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	22140000	USD
CY2021Q3	us-gaap	Stockholders Equity StockholdersEquity	739206000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	695853000	USD
	us-gaap	Net Income Loss NetIncomeLoss	23926000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	9708000	USD
	us-gaap	Amortization Of Esop Award AmortizationOfESOPAward	1074000	USD
	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	1227000	USD
	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	0	USD
	us-gaap	Restricted Stock Award Forfeitures RestrictedStockAwardForfeitures	0	USD
	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	175000	USD
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.33
	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.33
	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	12.24
	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	107000	USD
	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.37
	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	15.79
CY2021Q3	us-gaap	Stockholders Equity StockholdersEquity	739206000	USD
	us-gaap	Stock Issued During Period Value Acquisitions StockIssuedDuringPeriodValueAcquisitions	41447000	USD
CY2020Q3	us-gaap	Stockholders Equity StockholdersEquity	757398000	USD
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	753981000	USD
	us-gaap	Net Income Loss NetIncomeLoss	54551000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-5527000	USD
	us-gaap	Amortization Of Esop Award AmortizationOfESOPAward	1398000	USD
	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	750000	USD
	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	0	USD
	us-gaap	Restricted Stock Award Forfeitures RestrictedStockAwardForfeitures	0	USD
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.37
	us-gaap	Net Income Loss NetIncomeLoss	54551000	USD
	us-gaap	Net Income Loss NetIncomeLoss	23926000	USD
	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	-6223000	USD
	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	10269000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	2148000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	2301000	USD
	us-gaap	Depreciation Nonproduction DepreciationNonproduction	2919000	USD
	us-gaap	Depreciation Nonproduction DepreciationNonproduction	2603000	USD
	nfbk	Amortization Of Premiums And Deferred Loan Costs AmortizationOfPremiumsAndDeferredLoanCosts	807000	USD
	nfbk	Amortization Of Premiums And Deferred Loan Costs AmortizationOfPremiumsAndDeferredLoanCosts	3450000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	150000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	165000	USD
	nfbk	Operating Lease Right Of Use Asset Amortization OperatingLeaseRightOfUseAssetAmortization	3274000	USD
	nfbk	Operating Lease Right Of Use Asset Amortization OperatingLeaseRightOfUseAssetAmortization	3665000	USD
	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	2567000	USD
	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	2635000	USD
	us-gaap	Gain Loss On Sale Of Notes Receivable GainLossOnSaleOfNotesReceivable	1401000	USD
	us-gaap	Gain Loss On Sale Of Notes Receivable GainLossOnSaleOfNotesReceivable	665000	USD
	us-gaap	Debt Securities Available For Sale Gain Loss DebtSecuritiesAvailableForSaleGainLoss	976000	USD
	us-gaap	Debt Securities Available For Sale Gain Loss DebtSecuritiesAvailableForSaleGainLoss	105000	USD
	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	1096000	USD
	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	397000	USD
	us-gaap	Increase Decrease In Trading Securities IncreaseDecreaseInTradingSecurities	-626000	USD
	us-gaap	Increase Decrease In Trading Securities IncreaseDecreaseInTradingSecurities	-626000	USD
	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	-864000	USD
	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	-1963000	USD
	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	10970000	USD
	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	6632000	USD
	us-gaap	Increase Decrease In Other Accounts Payable And Accrued Liabilities IncreaseDecreaseInOtherAccountsPayableAndAccruedLiabilities	1297000	USD
	us-gaap	Increase Decrease In Other Accounts Payable And Accrued Liabilities IncreaseDecreaseInOtherAccountsPayableAndAccruedLiabilities	-9117000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	43403000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	29417000	USD
	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	116535000	USD
	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	162384000	USD
	us-gaap	Proceeds From Sale Of Finance Receivables ProceedsFromSaleOfFinanceReceivables	151559000	USD
	us-gaap	Proceeds From Sale Of Finance Receivables ProceedsFromSaleOfFinanceReceivables	48165000	USD
	us-gaap	Payments To Acquire Federal Home Loan Bank Stock PaymentsToAcquireFederalHomeLoanBankStock	220000	USD
	us-gaap	Payments To Acquire Federal Home Loan Bank Stock PaymentsToAcquireFederalHomeLoanBankStock	10497000	USD
	nfbk	Redemptions Of Federal Home Loan Bank Stock RedemptionsOfFederalHomeLoanBankStock	6525000	USD
	nfbk	Redemptions Of Federal Home Loan Bank Stock RedemptionsOfFederalHomeLoanBankStock	20610000	USD
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	409506000	USD
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	302378000	USD
	us-gaap	Payments To Acquire Marketable Securities PaymentsToAcquireMarketableSecurities	5000000	USD
	us-gaap	Payments To Acquire Marketable Securities PaymentsToAcquireMarketableSecurities	4276000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	370992000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	389799000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	1376000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	627000	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	207991000	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	17121000	USD
	nfbk	Proceeds From Sale Of Equity Securities ProceedsFromSaleOfEquitySecurities	34000	USD
	nfbk	Proceeds From Sale Of Equity Securities ProceedsFromSaleOfEquitySecurities	3115000	USD
	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	1021000	USD
	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	2716000	USD
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	1293000	USD
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	1576000	USD
	us-gaap	Cash Acquired From Acquisition CashAcquiredFromAcquisition	0	USD
	us-gaap	Cash Acquired From Acquisition CashAcquiredFromAcquisition	72875000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	206944000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	73917000	USD
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	64829000	USD
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	358339000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	18149000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	15905000	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	2262000	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	175000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	46973000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	107000	USD
	us-gaap	Increase Decrease In Advance Payments By Borrowers For Taxes And Insurance IncreaseDecreaseInAdvancePaymentsByBorrowersForTaxesAndInsurance	3819000	USD
	us-gaap	Increase Decrease In Advance Payments By Borrowers For Taxes And Insurance IncreaseDecreaseInAdvancePaymentsByBorrowersForTaxesAndInsurance	-2716000	USD
	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	15000	USD
	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	370901000	USD
	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	170000000	USD
	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	611000000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-164197000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	99687000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	86150000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	203021000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	87544000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	147818000	USD
CY2021Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	173694000	USD
CY2020Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	350839000	USD
	us-gaap	Interest Paid Net InterestPaidNet	13665000	USD
	us-gaap	Interest Paid Net InterestPaidNet	33468000	USD
	us-gaap	Income Taxes Paid IncomeTaxesPaid	27090000	USD
	us-gaap	Income Taxes Paid IncomeTaxesPaid	11910000	USD
	us-gaap	Allowance For Loan And Lease Losses Writeoffs Net AllowanceForLoanAndLeaseLossesWriteoffsNet	2875000	USD
	us-gaap	Allowance For Loan And Lease Losses Writeoffs Net AllowanceForLoanAndLeaseLossesWriteoffsNet	260000	USD
	us-gaap	Financing Receivable Reclassification To Held For Sale FinancingReceivableReclassificationToHeldForSale	131883000	USD
	us-gaap	Financing Receivable Reclassification To Held For Sale FinancingReceivableReclassificationToHeldForSale	47500000	USD
	us-gaap	Transfer Of Loans Held For Sale To Portfolio Loans1 TransferOfLoansHeldForSaleToPortfolioLoans1	1612000	USD
	us-gaap	Transfer Of Loans Held For Sale To Portfolio Loans1 TransferOfLoansHeldForSaleToPortfolioLoans1	0	USD
	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	100000	USD
	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	0	USD
	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	1596000	USD
	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	3028000	USD
	us-gaap	Noncash Or Part Noncash Acquisition Investments Acquired1 NoncashOrPartNoncashAcquisitionInvestmentsAcquired1	0	USD
	us-gaap	Noncash Or Part Noncash Acquisition Investments Acquired1 NoncashOrPartNoncashAcquisitionInvestmentsAcquired1	126931000	USD
	nfbk	Noncash Or Part Noncash Acquisition Loans And Leases Receivable Net NoncashOrPartNoncashAcquisitionLoansAndLeasesReceivableNet	0	USD
	nfbk	Noncash Or Part Noncash Acquisition Loans And Leases Receivable Net NoncashOrPartNoncashAcquisitionLoansAndLeasesReceivableNet	180431000	USD
	nfbk	Noncash Or Noncash Acquisition Accrued Interest Receivable NoncashOrNoncashAcquisitionAccruedInterestReceivable	0	USD
	nfbk	Noncash Or Noncash Acquisition Accrued Interest Receivable NoncashOrNoncashAcquisitionAccruedInterestReceivable	1415000	USD
	nfbk	Noncash Or Part Noncash Acquisition Bank Owned Life Insurance NoncashOrPartNoncashAcquisitionBankOwnedLifeInsurance	0	USD
	nfbk	Noncash Or Part Noncash Acquisition Bank Owned Life Insurance NoncashOrPartNoncashAcquisitionBankOwnedLifeInsurance	5714000	USD
	us-gaap	Noncash Or Part Noncash Acquisition Fixed Assets Acquired1 NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1	0	USD
	us-gaap	Noncash Or Part Noncash Acquisition Fixed Assets Acquired1 NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1	7789000	USD
	nfbk	Noncash Or Part Noncash Acquisition Goodwill Acquired NoncashOrPartNoncashAcquisitionGoodwillAcquired	0	USD
	nfbk	Noncash Or Part Noncash Acquisition Goodwill Acquired NoncashOrPartNoncashAcquisitionGoodwillAcquired	3183000	USD
	us-gaap	Noncash Or Part Noncash Acquisition Other Assets Acquired1 NoncashOrPartNoncashAcquisitionOtherAssetsAcquired1	0	USD
	us-gaap	Noncash Or Part Noncash Acquisition Other Assets Acquired1 NoncashOrPartNoncashAcquisitionOtherAssetsAcquired1	4702000	USD
	us-gaap	Noncash Or Part Noncash Acquisition Value Of Assets Acquired1 NoncashOrPartNoncashAcquisitionValueOfAssetsAcquired1	0	USD
	us-gaap	Noncash Or Part Noncash Acquisition Value Of Assets Acquired1 NoncashOrPartNoncashAcquisitionValueOfAssetsAcquired1	330165000	USD
	nfbk	Noncash Or Noncash Acquisition Deposits Assumed NoncashOrNoncashAcquisitionDepositsAssumed	0	USD
	nfbk	Noncash Or Noncash Acquisition Deposits Assumed NoncashOrNoncashAcquisitionDepositsAssumed	354592000	USD
	us-gaap	Noncash Or Part Noncash Acquisition Other Liabilities Assumed1 NoncashOrPartNoncashAcquisitionOtherLiabilitiesAssumed1	0	USD
	us-gaap	Noncash Or Part Noncash Acquisition Other Liabilities Assumed1 NoncashOrPartNoncashAcquisitionOtherLiabilitiesAssumed1	7001000	USD
	us-gaap	Noncash Or Part Noncash Acquisition Value Of Liabilities Assumed1 NoncashOrPartNoncashAcquisitionValueOfLiabilitiesAssumed1	0	USD
	us-gaap	Noncash Or Part Noncash Acquisition Value Of Liabilities Assumed1 NoncashOrPartNoncashAcquisitionValueOfLiabilitiesAssumed1	361593000	USD
	us-gaap	Noncash Or Part Noncash Acquisition Net Nonmonetary Assets Acquired Liabilities Assumed1 NoncashOrPartNoncashAcquisitionNetNonmonetaryAssetsAcquiredLiabilitiesAssumed1	0	USD
	us-gaap	Noncash Or Part Noncash Acquisition Net Nonmonetary Assets Acquired Liabilities Assumed1 NoncashOrPartNoncashAcquisitionNetNonmonetaryAssetsAcquiredLiabilitiesAssumed1	-31428000	USD
	nfbk	Cash And Cash Equivalents Acquired Net Of Cash Paid Related To Acquisition CashAndCashEquivalentsAcquiredNetOfCashPaidRelatedToAcquisition	0	USD
	nfbk	Cash And Cash Equivalents Acquired Net Of Cash Paid Related To Acquisition CashAndCashEquivalentsAcquiredNetOfCashPaidRelatedToAcquisition	72875000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	370000	USD
	nfbk	Noncash Or Part Noncash Acquisition Noncash Financial Or Equity Instrument Consideration Shares Issued Value NoncashOrPartNoncashAcquisitionNoncashFinancialOrEquityInstrumentConsiderationSharesIssuedValue	0	USD
	nfbk	Noncash Or Part Noncash Acquisition Noncash Financial Or Equity Instrument Consideration Shares Issued Value NoncashOrPartNoncashAcquisitionNoncashFinancialOrEquityInstrumentConsiderationSharesIssuedValue	41447000	USD
CY2021Q3	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	1074355000	USD
CY2021Q3	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	12327000	USD
CY2021Q3	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	1871000	USD
CY2021Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	1084811000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	1246673000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	18862000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	730000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	1264805000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Restricted DebtSecuritiesAvailableForSaleRestricted	498200000	USD
CY2021Q3	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	112500000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	0	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	208000000	USD
	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	976000	USD
	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	0	USD
CY2020Q3	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	4500000	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	48000	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	3000	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	17100000	USD
	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	122000	USD
	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	17000	USD
CY2021Q3	us-gaap	Debt Securities Trading Realized Gain Loss DebtSecuritiesTradingRealizedGainLoss	-75000	USD
	us-gaap	Debt Securities Trading Realized Gain Loss DebtSecuritiesTradingRealizedGainLoss	1100000	USD
CY2020Q3	us-gaap	Debt Securities Trading Realized Gain Loss DebtSecuritiesTradingRealizedGainLoss	763000	USD
	us-gaap	Debt Securities Trading Realized Gain Loss DebtSecuritiesTradingRealizedGainLoss	397000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	1578000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	330723000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	293000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	19105000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	1871000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	349828000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	719000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	242146000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	11000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	459000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	730000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	242605000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLoss	1700000	USD
CY2021Q3	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	5811000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	272000	USD
CY2021Q3	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	0	USD
CY2021Q3	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	6083000	USD
CY2020Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	7234000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	340000	USD
CY2020Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	0	USD
CY2020Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	7574000	USD
	us-gaap	Debt Securities Held To Maturity Sold Amount DebtSecuritiesHeldToMaturitySoldAmount	0	USD
	us-gaap	Debt Securities Held To Maturity Sold Amount DebtSecuritiesHeldToMaturitySoldAmount	0	USD
CY2021Q3	us-gaap	Held To Maturity Securities Restricted HeldToMaturitySecuritiesRestricted	736000	USD
CY2020Q4	nfbk	Debt Securities Held To Maturity Unrealized Loss Position Number Of Positions DebtSecuritiesHeldToMaturityUnrealizedLossPositionNumberOfPositions	0	security
CY2021Q3	nfbk	Debt Securities Held To Maturity Unrealized Loss Position Number Of Positions DebtSecuritiesHeldToMaturityUnrealizedLossPositionNumberOfPositions	0	security
CY2021Q3	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest	0	USD
CY2021Q3	us-gaap	Debt Securities Held To Maturity Accrued Interest After Allowance For Credit Loss DebtSecuritiesHeldToMaturityAccruedInterestAfterAllowanceForCreditLoss	18000	USD
CY2021Q3	us-gaap	Equity Securities Fv Ni And Without Readily Determinable Fair Value EquitySecuritiesFvNiAndWithoutReadilyDeterminableFairValue	5200000	USD
CY2020Q4	us-gaap	Equity Securities Fv Ni And Without Readily Determinable Fair Value EquitySecuritiesFvNiAndWithoutReadilyDeterminableFairValue	253000	USD
CY2021Q3	us-gaap	Notes Receivable Gross NotesReceivableGross	3816959000	USD
CY2020Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	3823238000	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	38862000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	37607000	USD
CY2021Q3	us-gaap	Notes Receivable Net NotesReceivableNet	3778097000	USD
CY2020Q4	us-gaap	Notes Receivable Net NotesReceivableNet	3785631000	USD
CY2021Q3	us-gaap	Loans Receivable Held For Sale Amount LoansReceivableHeldForSaleAmount	0	USD
CY2020Q4	us-gaap	Loans Receivable Held For Sale Amount LoansReceivableHeldForSaleAmount	19900000	USD
CY2021Q3	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	7200000	USD
CY2020Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	8500000	USD
	nfbk	Delinquent Status Classification Criteria Days Minimum DelinquentStatusClassificationCriteriaDaysMinimum	P90D
	nfbk	Delinquent Status Classification Criteria Days Minimum DelinquentStatusClassificationCriteriaDaysMinimum	P90D
CY2021Q3	nfbk	Principal Balance Threshold For Non Accrual Status PrincipalBalanceThresholdForNonAccrualStatus	500000	USD
CY2021Q3	nfbk	Loans Deemed To Be Impaired Non Accrual Amount LoansDeemedToBeImpairedNonAccrualAmount	4300000	USD
CY2020Q4	nfbk	Loans Deemed To Be Impaired Non Accrual Amount LoansDeemedToBeImpairedNonAccrualAmount	5500000	USD
CY2021Q3	nfbk	Principal Balance Threshold For Non Accrual Status PrincipalBalanceThresholdForNonAccrualStatus	500000	USD
CY2021Q3	nfbk	Loans On Non Accrual Status With Principal Balances Below Threshold Definition Of Impaired Loan LoansOnNonAccrualStatusWithPrincipalBalancesBelowThresholdDefinitionOfImpairedLoan	2900000	USD
CY2020Q4	nfbk	Loans On Non Accrual Status With Principal Balances Below Threshold Definition Of Impaired Loan LoansOnNonAccrualStatusWithPrincipalBalancesBelowThresholdDefinitionOfImpairedLoan	3000000	USD
	nfbk	Delinquent Status Classification Criteria Days Minimum DelinquentStatusClassificationCriteriaDaysMinimum	P90D
CY2020	nfbk	Delinquent Status Classification Criteria Days Minimum DelinquentStatusClassificationCriteriaDaysMinimum	P90D
CY2021Q3	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	272000	USD
CY2020Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	1100000	USD
CY2021Q3	us-gaap	Loans Receivable Held For Sale Amount LoansReceivableHeldForSaleAmount	0	USD
CY2020Q4	us-gaap	Loans Receivable Held For Sale Amount LoansReceivableHeldForSaleAmount	19900000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	7800000	USD
CY2020	nfbk	Delinquent Status Classification Criteria Days Minimum DelinquentStatusClassificationCriteriaDaysMinimum	P90D
	nfbk	Delinquent Status Classification Criteria Days Minimum DelinquentStatusClassificationCriteriaDaysMinimum	P90D
CY2021Q3	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	7245000	USD
CY2021Q3	nfbk	Financing Receivable Nonaccrual Unpaid Principal Balance FinancingReceivableNonaccrualUnpaidPrincipalBalance	8367000	USD
CY2021Q3	us-gaap	Financing Receivable Nonaccrual No Allowance FinancingReceivableNonaccrualNoAllowance	4277000	USD
CY2021Q3	us-gaap	Financing Receivable Nonaccrual Interest Income FinancingReceivableNonaccrualInterestIncome	51000	USD
	us-gaap	Financing Receivable Nonaccrual Interest Income FinancingReceivableNonaccrualInterestIncome	146000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	13242000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	15512000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	73000	USD
CY2020Q3	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	19687000	USD
CY2020Q3	us-gaap	Impaired Financing Receivable Interest Income Cash Basis Method ImpairedFinancingReceivableInterestIncomeCashBasisMethod	110000	USD
	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	20211000	USD
	us-gaap	Impaired Financing Receivable Interest Income Cash Basis Method ImpairedFinancingReceivableInterestIncomeCashBasisMethod	546000	USD
CY2021Q3	nfbk	Financing Receivable Impaired Secured By Collateral FinancingReceivableImpairedSecuredByCollateral	9100000	USD
CY2020Q4	nfbk	Financing Receivable Impaired Secured By Collateral FinancingReceivableImpairedSecuredByCollateral	10200000	USD
	nfbk	Financing Receivable Modification Number Of Borrowers FinancingReceivableModificationNumberOfBorrowers	1	loan
	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	75000	USD
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	75000	USD
	nfbk	Financing Receivable Modification Number Of Borrowers FinancingReceivableModificationNumberOfBorrowers	3	loan
	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	731000	USD
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	731000	USD
CY2021Q3	nfbk	Financing Receivable Modification Number Of Borrowers FinancingReceivableModificationNumberOfBorrowers	1	borrower
	nfbk	Financing Receivable Modification Number Of Borrowers FinancingReceivableModificationNumberOfBorrowers	1	borrower
	nfbk	Financing Receivable Modification Number Of Borrowers FinancingReceivableModificationNumberOfBorrowers	3	borrower
CY2021Q3	nfbk	Trouble Debt Restructuring Amount TroubleDebtRestructuringAmount	10800000	USD
CY2020Q4	nfbk	Trouble Debt Restructuring Amount TroubleDebtRestructuringAmount	12100000	USD
	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	0	contract
	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	0	contract
CY2021Q3	us-gaap	Financing Receivable Accrued Interest After Allowance For Credit Loss FinancingReceivableAccruedInterestAfterAllowanceForCreditLoss	9500000	USD
CY2021Q3	nfbk	Financing Receivable Threshold Individually Evaluated For Impairment FinancingReceivableThresholdIndividuallyEvaluatedForImpairment	500000	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	32000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	73000	USD
CY2021Q2	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	1808000	USD
CY2020Q4	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	808000	USD
CY2021Q3	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	265000	USD
	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	528000	USD
CY2021Q3	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	2073000	USD
CY2021Q3	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	2073000	USD
CY2021Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	39493000	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	544000	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	61000	USD
CY2021Q3	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	-148000	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	38862000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	38520000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	12000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	43000	USD
CY2020Q3	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	165000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	38716000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	37607000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	2988000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	113000	USD
	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	-6223000	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	38862000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	28707000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	703000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	443000	USD
	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	10269000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	38716000	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	32000	USD
CY2021Q3	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	38830000	USD
CY2021Q3	us-gaap	Notes Receivable Gross NotesReceivableGross	3816959000	USD
CY2021Q3	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	11731000	USD
CY2021Q3	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	3732281000	USD
CY2021Q3	nfbk	Financing Receivable Not Evaluated For Impairment FinancingReceivableNotEvaluatedForImpairment	72947000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	73000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	37534000	USD
CY2020Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	3823238000	USD
CY2020Q4	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	13242000	USD
CY2020Q4	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	3683461000	USD
CY2020Q4	nfbk	Financing Receivable Not Evaluated For Impairment FinancingReceivableNotEvaluatedForImpairment	126535000	USD
CY2021Q3	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	869008000	USD
CY2020Q4	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	695831000	USD
CY2021Q3	us-gaap	Deposits Negotiable Order Of Withdrawal Now DepositsNegotiableOrderOfWithdrawalNOW	1056876000	USD
CY2020Q4	us-gaap	Deposits Negotiable Order Of Withdrawal Now DepositsNegotiableOrderOfWithdrawalNOW	905208000	USD
CY2021Q3	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	1807529000	USD
CY2020Q4	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	1953885000	USD
CY2021Q3	us-gaap	Time Deposits TimeDeposits	407967000	USD
CY2020Q4	us-gaap	Time Deposits TimeDeposits	521627000	USD
CY2021Q3	us-gaap	Deposits Deposits	4141380000	USD
CY2020Q4	us-gaap	Deposits Deposits	4076551000	USD
CY2021Q3	us-gaap	Interest Expense Domestic Deposit Liabilities Demand InterestExpenseDomesticDepositLiabilitiesDemand	671000	USD
CY2020Q3	us-gaap	Interest Expense Domestic Deposit Liabilities Demand InterestExpenseDomesticDepositLiabilitiesDemand	2023000	USD
	us-gaap	Interest Expense Domestic Deposit Liabilities Demand InterestExpenseDomesticDepositLiabilitiesDemand	2448000	USD
	us-gaap	Interest Expense Domestic Deposit Liabilities Demand InterestExpenseDomesticDepositLiabilitiesDemand	8990000	USD
CY2021Q3	us-gaap	Interest Expense Domestic Deposit Liabilities Certificates Of Deposit InterestExpenseDomesticDepositLiabilitiesCertificatesOfDeposit	749000	USD
CY2020Q3	us-gaap	Interest Expense Domestic Deposit Liabilities Certificates Of Deposit InterestExpenseDomesticDepositLiabilitiesCertificatesOfDeposit	3620000	USD
	us-gaap	Interest Expense Domestic Deposit Liabilities Certificates Of Deposit InterestExpenseDomesticDepositLiabilitiesCertificatesOfDeposit	2513000	USD
	us-gaap	Interest Expense Domestic Deposit Liabilities Certificates Of Deposit InterestExpenseDomesticDepositLiabilitiesCertificatesOfDeposit	13405000	USD
CY2021Q3	us-gaap	Interest Expense Deposits InterestExpenseDeposits	1420000	USD
CY2020Q3	us-gaap	Interest Expense Deposits InterestExpenseDeposits	5643000	USD
	us-gaap	Interest Expense Deposits InterestExpenseDeposits	4961000	USD
	us-gaap	Interest Expense Deposits InterestExpenseDeposits	22395000	USD
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod	41090	shares
	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Nonvested Options Forfeited Weighted Average Grant Date Fair Value SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedOptionsForfeitedWeightedAverageGrantDateFairValue	3.96
	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice	13.62
	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	262801	shares
	nfbk	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageGrantDateFairValue	3.93
	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	13.56
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	2214193	shares
CY2020Q4	nfbk	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageGrantDateFairValue	4.01
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	13.94
CY2020	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P3Y11M15D
CY2021Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	1910302	shares
CY2021Q3	nfbk	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageGrantDateFairValue	4.02
CY2021Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	14.00
	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P3Y3M
CY2021Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber	1893223	shares
CY2021Q3	nfbk	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageGrantDateFairValue	4.02
CY2021Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice	13.98
	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P3Y3M
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Number ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber	104010	shares
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue	15.91
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod	176930	shares
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	12.59
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod	38470	shares
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue	15.81
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Forfeited In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod	14138	shares
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Forfeitures Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue	13.86
CY2021Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Number ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber	228332	shares
CY2021Q3	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue	13.48
CY2021Q3	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	248000	USD
CY2020Q3	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	217000	USD
	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	752000	USD
	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	1100000	USD
CY2020Q4	nfbk	Estimated Fair Value Of Impaired Loans Held For Investment EstimatedFairValueOfImpairedLoansHeldForInvestment	5300000	USD
CY2021Q3	nfbk	Investment Owned At Net Asset Value InvestmentOwnedAtNetAssetValue	5000000	USD
CY2021Q3	us-gaap	Loans Receivable Fair Value Disclosure LoansReceivableFairValueDisclosure	4280000	USD
CY2020Q4	us-gaap	Loans Receivable Fair Value Disclosure LoansReceivableFairValueDisclosure	5325000	USD
CY2021Q3	nfbk	Other Real Estate Owned Fair Value Disclosure OtherRealEstateOwnedFairValueDisclosure	100000	USD
CY2020Q4	nfbk	Other Real Estate Owned Fair Value Disclosure OtherRealEstateOwnedFairValueDisclosure	0	USD
CY2021Q3	nfbk	Principal Amount Outstanding Of Impaired Loans Heldfor Investment Heldfor Sale PrincipalAmountOutstandingOfImpairedLoansHeldforInvestmentHeldforSale	6300000	USD
CY2020Q4	nfbk	Principal Amount Outstanding Of Impaired Loans Heldfor Investment Heldfor Sale PrincipalAmountOutstandingOfImpairedLoansHeldforInvestmentHeldforSale	7400000	USD
CY2021Q3	nfbk	Estimated Fair Value Of Impaired Loans Held For Investment EstimatedFairValueOfImpairedLoansHeldForInvestment	4300000	USD
	nfbk	Impaired Financing Receivable Reserve Increase Decrease ImpairedFinancingReceivableReserveIncreaseDecrease	42000	USD
	nfbk	Impaired Financing Receivable Reserve Increase Decrease ImpairedFinancingReceivableReserveIncreaseDecrease	166000	USD
	nfbk	Impaired Financing Receivables Charge Off ImpairedFinancingReceivablesChargeOff	2900000	USD
	nfbk	Impaired Financing Receivables Charge Off ImpairedFinancingReceivablesChargeOff	260000	USD
	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	100000	USD
CY2021Q3	nfbk	Investment Owned At Net Asset Value InvestmentOwnedAtNetAssetValue	5000000	USD
CY2020Q4	us-gaap	Loans Held For Sale Fair Value Disclosure LoansHeldForSaleFairValueDisclosure	19895000	USD
CY2021Q3	us-gaap	Net Income Loss NetIncomeLoss	16080000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	8582000	USD
	us-gaap	Net Income Loss NetIncomeLoss	54551000	USD
	us-gaap	Net Income Loss NetIncomeLoss	23926000	USD
CY2021Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	48095473	shares
CY2020Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	50707691	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	48838396	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	48131005	shares
CY2021Q3	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	390623	shares
CY2020Q3	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	12112	shares
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	298641	shares
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	79276	shares
CY2021Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	48486096	shares
CY2020Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	50719803	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	49137037	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	48210281	shares
CY2021Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.33
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.17
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.12
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.50
CY2021Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.33
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.17
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.11
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.50
CY2021Q3	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	125744	shares
CY2020Q3	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	2287010	shares
	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	417955	shares
	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	1868511	shares
CY2021Q3	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	35100000	USD
CY2021Q3	us-gaap	Operating Lease Liability OperatingLeaseLiability	41100000	USD
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	36700000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	42700000	USD
CY2021Q3	us-gaap	Operating Lease Cost OperatingLeaseCost	1409000	USD
CY2020Q3	us-gaap	Operating Lease Cost OperatingLeaseCost	2073000	USD
	us-gaap	Operating Lease Cost OperatingLeaseCost	4317000	USD
	us-gaap	Operating Lease Cost OperatingLeaseCost	4935000	USD
CY2021Q3	us-gaap	Variable Lease Cost VariableLeaseCost	974000	USD
CY2020Q3	us-gaap	Variable Lease Cost VariableLeaseCost	878000	USD
	us-gaap	Variable Lease Cost VariableLeaseCost	3219000	USD
	us-gaap	Variable Lease Cost VariableLeaseCost	2378000	USD
CY2021Q3	us-gaap	Lease Cost LeaseCost	2383000	USD
CY2020Q3	us-gaap	Lease Cost LeaseCost	2951000	USD
	us-gaap	Lease Cost LeaseCost	7536000	USD
	us-gaap	Lease Cost LeaseCost	7313000	USD
CY2021Q3	us-gaap	Operating Lease Payments OperatingLeasePayments	1568000	USD
CY2020Q3	us-gaap	Operating Lease Payments OperatingLeasePayments	2111000	USD
	us-gaap	Operating Lease Payments OperatingLeasePayments	4967000	USD
	us-gaap	Operating Lease Payments OperatingLeasePayments	5180000	USD
CY2021Q3	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	1596000	USD
CY2020Q3	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	0	USD
	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	1596000	USD
	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	3028000	USD
CY2021Q3	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P11Y10M20D
CY2020Q3	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P12Y4M20D
CY2021Q3	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0355
CY2020Q3	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0355
CY2021Q3	us-gaap	Lessee Operating Lease Liability Payments Remainder Of Fiscal Year LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear	1571000	USD
CY2021Q3	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	5923000	USD
CY2021Q3	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	5802000	USD
CY2021Q3	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	5372000	USD
CY2021Q3	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	5024000	USD
CY2021Q3	nfbk	Lessee Operating Lease Liability Payments Due After Year Four LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFour	28382000	USD
CY2021Q3	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	52074000	USD
CY2021Q3	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	10984000	USD
CY2021Q3	us-gaap	Operating Lease Liability OperatingLeaseLiability	41090000	USD
CY2021Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	1370000	USD
CY2020Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	1009000	USD
	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	3894000	USD
	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	2795000	USD
CY2021Q3	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	862000	USD
CY2020Q3	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	894000	USD
	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	2567000	USD
	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	2635000	USD
CY2021Q3	us-gaap	Debt Securities Available For Sale Gain Loss DebtSecuritiesAvailableForSaleGainLoss	370000	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Gain Loss DebtSecuritiesAvailableForSaleGainLoss	45000	USD
	us-gaap	Debt Securities Available For Sale Gain Loss DebtSecuritiesAvailableForSaleGainLoss	976000	USD
	us-gaap	Debt Securities Available For Sale Gain Loss DebtSecuritiesAvailableForSaleGainLoss	105000	USD
CY2021Q3	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	-75000	USD
CY2020Q3	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	763000	USD
	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	1096000	USD
	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	397000	USD
CY2021Q3	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	0	USD
CY2020Q3	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	0	USD
	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	1401000	USD
	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	665000	USD
CY2021Q3	us-gaap	Derivative Gain Loss On Derivative Net DerivativeGainLossOnDerivativeNet	0	USD
CY2020Q3	us-gaap	Derivative Gain Loss On Derivative Net DerivativeGainLossOnDerivativeNet	307000	USD
	us-gaap	Derivative Gain Loss On Derivative Net DerivativeGainLossOnDerivativeNet	0	USD
	us-gaap	Derivative Gain Loss On Derivative Net DerivativeGainLossOnDerivativeNet	691000	USD
CY2021Q3	us-gaap	Revenue Not From Contract With Customer Other RevenueNotFromContractWithCustomerOther	101000	USD
CY2020Q3	us-gaap	Revenue Not From Contract With Customer Other RevenueNotFromContractWithCustomerOther	4000	USD
	us-gaap	Revenue Not From Contract With Customer Other RevenueNotFromContractWithCustomerOther	246000	USD
	us-gaap	Revenue Not From Contract With Customer Other RevenueNotFromContractWithCustomerOther	81000	USD
CY2021Q3	us-gaap	Noninterest Income NoninterestIncome	2628000	USD
CY2020Q3	us-gaap	Noninterest Income NoninterestIncome	3022000	USD
	us-gaap	Noninterest Income NoninterestIncome	10180000	USD
	us-gaap	Noninterest Income NoninterestIncome	7369000	USD
CY2021Q3	us-gaap	Derivative Gain Loss On Derivative Net DerivativeGainLossOnDerivativeNet	0	USD
	us-gaap	Derivative Gain Loss On Derivative Net DerivativeGainLossOnDerivativeNet	0	USD
CY2020Q3	us-gaap	Derivative Gain Loss On Derivative Net DerivativeGainLossOnDerivativeNet	307000	USD
	us-gaap	Derivative Gain Loss On Derivative Net DerivativeGainLossOnDerivativeNet	691000	USD

Files In Submission

Name	View Source	Status
0001493225-21-000115-index-headers.html	Edgar Link	pending
0001493225-21-000115-index.html	Edgar Link	pending
0001493225-21-000115.txt	Edgar Link	pending
0001493225-21-000115-xbrl.zip	Edgar Link	pending
ex101amendmenttoemployment.htm	Edgar Link	pending
ex311-2021x9x30.htm	Edgar Link	pending
ex312-2021x9x30.htm	Edgar Link	pending
ex32-2021x9x30.htm	Edgar Link	pending
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Financial_Report.xlsx	Edgar Link	pending
MetaLinks.json	Edgar Link	pending
nfbk-20210930.htm	Edgar Link	pending
nfbk-20210930.xsd	Edgar Link	pending
nfbk-20210930_cal.xml	Edgar Link	unprocessable
nfbk-20210930_def.xml	Edgar Link	unprocessable
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$NFBK
Northfield Bancorp, Inc. Stock $nfbk

2021 Q4 Form 10-Q Financial Statement

#000149322521000115 Filed on November 09, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$NFBK Northfield Bancorp, Inc. Stock $nfbk

2021 Q4 Form 10-Q Financial Statement

#000149322521000115 Filed on November 09, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$NFBK
Northfield Bancorp, Inc. Stock $nfbk