$NFBK
Northfield Bancorp, Inc. Stock $nfbk

$nfbk Overview Financials Valuation SEC Filings Company Website

2020 Q2 Form 10-Q Financial Statement

#000149322520000104 Filed on August 10, 2020

Income Statement

Concept	2020 Q2	2019 Q2	2019 Q1
Revenue	$40.91M	$40.19M	$39.47M
YoY Change	1.79%	11.85%	13.79%
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	$860.0K	$840.0K	$840.0K
YoY Change	2.38%	-1.18%	-1.18%
% of Gross Profit
Operating Expenses
YoY Change
Operating Profit
YoY Change
Interest Expense	$10.68M	$13.03M	$12.14M
YoY Change	-18.05%	59.63%	70.02%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	$14.69M	$10.48M	$11.38M
YoY Change	40.14%	-16.16%	-11.01%
Income Tax	$3.899M	$2.280M	$2.610M
% Of Pretax Income	26.54%	21.75%	22.93%
Net Earnings	$10.79M	$8.204M	$8.771M
YoY Change	31.56%	-22.69%	-16.03%
Net Earnings / Revenue	26.38%	20.41%	22.22%
Basic Earnings Per Share	$0.23	$0.18	$0.19
Diluted Earnings Per Share	$0.23	$0.17	$0.19
COMMON SHARES
Basic Shares Outstanding	46.84M shares	46.86M shares	46.94M shares
Diluted Shares Outstanding	46.87M shares	47.27M shares	47.29M shares

Balance Sheet

Concept	2020 Q2	2019 Q2	2019 Q1
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$110.9M	$46.91M	$85.83M
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	$25.27M	$25.70M	$25.21M
YoY Change	-1.67%	2.56%	-0.29%
Goodwill	$38.41M	$38.41M	$38.41M
YoY Change	0.0%	0.0%	0.0%
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	$5.042B	$4.768B	$4.555B
YoY Change	5.73%	13.85%	11.95%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$19.90M	$20.80M	$20.70M
YoY Change	-4.33%	15.56%	13.74%
Accrued Expenses	$71.20M	$71.10M	$70.80M
YoY Change	0.14%	146.02%	51.28%
Deferred Revenue
YoY Change
Short-Term Debt	$75.00M	$75.00M
YoY Change	0.0%
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$91.10M	$91.90M	$91.50M
YoY Change	-0.87%	95.95%	40.77%
LONG-TERM LIABILITIES
Long-Term Debt	$541.3M	$620.1M	$409.2M
YoY Change	-12.71%	18.27%	-10.32%
Other Long-Term Liabilities
YoY Change
Total Long-Term Liabilities	$541.3M	$620.1M	$409.2M
YoY Change	-12.71%	18.27%	-10.32%
TOTAL LIABILITIES
Total Short-Term Liabilities	$91.10M	$91.90M	$91.50M
Total Long-Term Liabilities	$541.3M	$620.1M	$409.2M
Total Liabilities	$4.329B	$4.087B	$3.876B
YoY Change	5.92%	15.51%	13.12%
SHAREHOLDERS EQUITY
Retained Earnings	$327.6M	$309.6M	$306.6M
YoY Change	5.82%	5.7%	6.85%
Common Stock	$609.0K	$609.0K	$609.0K
YoY Change	0.0%	0.0%	0.0%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$159.6M	$161.0M	$150.9M
YoY Change	-0.88%	3.94%	-5.48%
Treasury Stock Shares	11.67M shares	11.82M shares	11.16M shares
Shareholders Equity	$712.6M	$681.1M	$679.4M
YoY Change
Total Liabilities & Shareholders Equity	$5.042B	$4.768B	$4.555B
YoY Change	5.73%	13.85%	11.95%

Cashflow Statement

Concept	2020 Q2	2019 Q2	2019 Q1
OPERATING ACTIVITIES
Net Income	$10.79M	$8.204M	$8.771M
YoY Change	31.56%	-22.69%	-16.03%
Depreciation, Depletion And Amortization	$860.0K	$840.0K	$840.0K
YoY Change	2.38%	-1.18%	-1.18%
Cash From Operating Activities	$14.17M	$6.430M	$9.629M
YoY Change	120.37%	-48.31%	-29.21%
INVESTING ACTIVITIES
Capital Expenditures	-$410.0K	-$1.260M	$377.0K
YoY Change	-67.46%	137.74%	22.8%
Acquisitions
YoY Change
Other Investing Activities	-$45.74M	-$239.8M	-$89.22M
YoY Change	-80.93%	81.76%	25.89%
Cash From Investing Activities	-$46.16M	-$241.1M	-$89.60M
YoY Change	-80.85%	81.99%	25.87%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net			$25.00M
YoY Change			-91.4%
Cash From Financing Activities	28.19M	195.7M	$88.03M
YoY Change	-85.6%	55.09%	68.28%
NET CHANGE
Cash From Operating Activities	14.17M	6.430M	$9.629M
Cash From Investing Activities	-46.16M	-241.1M	-$89.60M
Cash From Financing Activities	28.19M	195.7M	$88.03M
Net Change In Cash	-3.800M	-38.92M	$8.063M
YoY Change	-90.24%	-730.79%	-253.14%
FREE CASH FLOW
Cash From Operating Activities	$14.17M	$6.430M	$9.629M
Capital Expenditures	-$410.0K	-$1.260M	$377.0K
Free Cash Flow	$14.58M	$7.690M	$9.252M
YoY Change	89.6%	-40.71%	-30.41%

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	2020
	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	Q2
	dei	Amendment Flag AmendmentFlag	false
	dei	Document Type DocumentType	10-Q
	dei	Document Quarterly Report DocumentQuarterlyReport	true
	dei	Document Period End Date DocumentPeriodEndDate	2020-06-30
	dei	Document Transition Report DocumentTransitionReport	false
	dei	Entity File Number EntityFileNumber	001-35791
	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	Large 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	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	460000	USD
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	86000	USD
CY2020Q2	us-gaap	Noninterest Income NoninterestIncome	4238000	USD
CY2019Q2	us-gaap	Noninterest Income NoninterestIncome	2566000	USD
	us-gaap	Noninterest Income NoninterestIncome	4346000	USD
	us-gaap	Noninterest Income NoninterestIncome	5880000	USD
CY2020Q2	us-gaap	Labor And Related Expense LaborAndRelatedExpense	10444000	USD
CY2019Q2	us-gaap	Labor And Related Expense LaborAndRelatedExpense	9837000	USD
	us-gaap	Labor And Related Expense LaborAndRelatedExpense	17733000	USD
	us-gaap	Labor And Related Expense LaborAndRelatedExpense	20857000	USD
CY2020Q2	us-gaap	Occupancy Net OccupancyNet	3018000	USD
CY2019Q2	us-gaap	Occupancy Net OccupancyNet	3120000	USD
	us-gaap	Occupancy Net OccupancyNet	6078000	USD
	us-gaap	Occupancy Net OccupancyNet	6402000	USD
CY2020Q2	us-gaap	Equipment Expense EquipmentExpense	349000	USD
CY2019Q2	us-gaap	Equipment Expense EquipmentExpense	265000	USD
	us-gaap	Equipment Expense EquipmentExpense	682000	USD
	us-gaap	Equipment Expense EquipmentExpense	524000	USD
CY2020Q2	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	1612000	USD
CY2019Q2	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	1437000	USD
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	3072000	USD
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	2700000	USD
CY2020Q2	us-gaap	Professional Fees ProfessionalFees	1045000	USD
CY2019Q2	us-gaap	Professional Fees ProfessionalFees	811000	USD
	us-gaap	Professional Fees ProfessionalFees	2154000	USD
	us-gaap	Professional Fees ProfessionalFees	1558000	USD
CY2020Q2	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	343000	USD
CY2019Q2	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	1331000	USD
	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	1161000	USD
	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	2095000	USD
CY2020Q2	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	216000	USD
CY2019Q2	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	255000	USD
	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	216000	USD
	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	532000	USD
CY2020Q2	us-gaap	Other Noninterest Expense OtherNoninterestExpense	828000	USD
CY2019Q2	us-gaap	Other Noninterest Expense OtherNoninterestExpense	1694000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	2441000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	3286000	USD
CY2020Q2	us-gaap	Noninterest Expense NoninterestExpense	17855000	USD
CY2019Q2	us-gaap	Noninterest Expense NoninterestExpense	18750000	USD
	us-gaap	Noninterest Expense NoninterestExpense	33537000	USD
	us-gaap	Noninterest Expense NoninterestExpense	37954000	USD
CY2020Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	14692000	USD
CY2019Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	10484000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	20868000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	21865000	USD
CY2020Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	3899000	USD
CY2019Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	2280000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	5524000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	4890000	USD
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	10793000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	8204000	USD
	us-gaap	Net Income Loss NetIncomeLoss	15344000	USD
	us-gaap	Net Income Loss NetIncomeLoss	16975000	USD
CY2020Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.23
CY2019Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.18
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.33
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.36
CY2020Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.23
CY2019Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.17
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.33
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.36
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	10793000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	8204000	USD
	us-gaap	Net Income Loss NetIncomeLoss	15344000	USD
	us-gaap	Net Income Loss NetIncomeLoss	16975000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	5603000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	9930000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	13913000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	18693000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	73000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	59000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	60000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	214000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	5530000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	9871000	USD
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	13853000	USD
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	18479000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	1568000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	2779000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	3894000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	5232000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	20000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	17000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	25320000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	17000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	60000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	3982000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	7109000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	9976000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	13307000	USD
CY2020Q2	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	14775000	USD
CY2019Q2	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	15313000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	30282000	USD
CY2019Q1	us-gaap	Stockholders Equity StockholdersEquity	679440000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	8204000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	7109000	USD
CY2019Q2	us-gaap	Amortization Of Esop Award AmortizationOfESOPAward	457000	USD
CY2019Q2	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	1112000	USD
CY2019Q2	us-gaap	Restricted Stock Award Forfeitures RestrictedStockAwardForfeitures	0	USD
CY2019Q2	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	34000	USD
CY2019Q2	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.11
CY2019Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.11
CY2019Q2	us-gaap	Dividends Common Stock DividendsCommonStock	5198000	USD
CY2019Q2	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	15.16
CY2019Q2	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	10065000	USD
CY2019Q2	us-gaap	Stockholders Equity StockholdersEquity	681093000	USD
CY2020Q1	us-gaap	Stockholders Equity StockholdersEquity	702316000	USD
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	10793000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	3982000	USD
CY2020Q2	us-gaap	Amortization Of Esop Award AmortizationOfESOPAward	327000	USD
CY2020Q2	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	433000	USD
CY2020Q2	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	0	USD
CY2020Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.11
CY2020Q2	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.11
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	13307000	USD
	us-gaap	Amortization Of Esop Award AmortizationOfESOPAward	893000	USD
	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	2440000	USD
CY2020Q2	us-gaap	Dividends Common Stock DividendsCommonStock	5168000	USD
CY2020Q2	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	12.24
CY2020Q2	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	107000	USD
CY2020Q2	us-gaap	Stockholders Equity StockholdersEquity	712576000	USD
CY2018Q4	us-gaap	Stockholders Equity StockholdersEquity	666439000	USD
	us-gaap	Net Income Loss NetIncomeLoss	16975000	USD
	us-gaap	Restricted Stock Award Forfeitures RestrictedStockAwardForfeitures	0	USD
	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	1029000	USD
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.21
	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.21
	us-gaap	Dividends Common Stock DividendsCommonStock	9925000	USD
	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	15.16
	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	10065000	USD
CY2019Q2	us-gaap	Stockholders Equity StockholdersEquity	681093000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	695853000	USD
	us-gaap	Net Income Loss NetIncomeLoss	15344000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	9976000	USD
	us-gaap	Amortization Of Esop Award AmortizationOfESOPAward	773000	USD
	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	881000	USD
	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	0	USD
	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	175000	USD
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.22
	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.22
	us-gaap	Dividends Common Stock DividendsCommonStock	10319000	USD
	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	12.24
	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	107000	USD
CY2020Q2	us-gaap	Stockholders Equity StockholdersEquity	712576000	USD
	us-gaap	Net Income Loss NetIncomeLoss	15344000	USD
	us-gaap	Net Income Loss NetIncomeLoss	16975000	USD
	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	10104000	USD
	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	550000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	1654000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	3333000	USD
	us-gaap	Depreciation Nonproduction DepreciationNonproduction	1612000	USD
	us-gaap	Depreciation Nonproduction DepreciationNonproduction	1542000	USD
	nfbk	Amortization Of Premiums And Deferred Loan Costs AmortizationOfPremiumsAndDeferredLoanCosts	1900000	USD
	nfbk	Amortization Of Premiums And Deferred Loan Costs AmortizationOfPremiumsAndDeferredLoanCosts	2034000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	110000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	136000	USD
	nfbk	Operating Lease Right Of Use Asset Amortization OperatingLeaseRightOfUseAssetAmortization	2166000	USD
	nfbk	Operating Lease Right Of Use Asset Amortization OperatingLeaseRightOfUseAssetAmortization	2196000	USD
	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	1741000	USD
	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	1804000	USD
	us-gaap	Gain Loss On Sale Of Loans And Leases GainLossOnSaleOfLoansAndLeases	665000	USD
	us-gaap	Gain Loss On Sale Of Loans And Leases GainLossOnSaleOfLoansAndLeases		USD
	us-gaap	Proceeds From Sale Of Loans Held For Sale ProceedsFromSaleOfLoansHeldForSale	48165000	USD
	us-gaap	Interest Paid Net InterestPaidNet	24930000	USD
	us-gaap	Income Taxes Paid IncomeTaxesPaid	7375000	USD
	us-gaap	Income Taxes Paid IncomeTaxesPaid	5732000	USD
	us-gaap	Proceeds From Sale Of Loans Held For Sale ProceedsFromSaleOfLoansHeldForSale	0	USD
	us-gaap	Payments For Origination And Purchases Of Loans Held For Sale PaymentsForOriginationAndPurchasesOfLoansHeldForSale	47500000	USD
	us-gaap	Payments For Origination And Purchases Of Loans Held For Sale PaymentsForOriginationAndPurchasesOfLoansHeldForSale	0	USD
	us-gaap	Debt Securities Available For Sale Gain Loss DebtSecuritiesAvailableForSaleGainLoss	60000	USD
	us-gaap	Debt Securities Available For Sale Gain Loss DebtSecuritiesAvailableForSaleGainLoss	214000	USD
	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	-366000	USD
	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	1429000	USD
	us-gaap	Increase Decrease In Trading Securities IncreaseDecreaseInTradingSecurities	-762000	USD
	us-gaap	Increase Decrease In Trading Securities IncreaseDecreaseInTradingSecurities	-183000	USD
	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	-1584000	USD
	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	1157000	USD
	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	3325000	USD
	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	2457000	USD
	us-gaap	Increase Decrease In Other Accounts Payable And Accrued Liabilities IncreaseDecreaseInOtherAccountsPayableAndAccruedLiabilities	-3691000	USD
	us-gaap	Increase Decrease In Other Accounts Payable And Accrued Liabilities IncreaseDecreaseInOtherAccountsPayableAndAccruedLiabilities	-3828000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	26785000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	16060000	USD
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	132052000	USD
	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	153113000	USD
	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	53140000	USD
	us-gaap	Payments To Acquire Finance Receivables PaymentsToAcquireFinanceReceivables	0	USD
	us-gaap	Payments To Acquire Finance Receivables PaymentsToAcquireFinanceReceivables	41527000	USD
	us-gaap	Payments To Acquire Federal Home Loan Bank Stock PaymentsToAcquireFederalHomeLoanBankStock	10497000	USD
	us-gaap	Payments To Acquire Federal Home Loan Bank Stock PaymentsToAcquireFederalHomeLoanBankStock	14291000	USD
	nfbk	Redemptions Of Federal Home Loan Bank Stock RedemptionsOfFederalHomeLoanBankStock	20610000	USD
	nfbk	Redemptions Of Federal Home Loan Bank Stock RedemptionsOfFederalHomeLoanBankStock	4478000	USD
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	366902000	USD
	us-gaap	Payments To Acquire Marketable Securities PaymentsToAcquireMarketableSecurities	24000	USD
	us-gaap	Payments To Acquire Marketable Securities PaymentsToAcquireMarketableSecurities	1048000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	232838000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	108361000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	106000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	607000	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	12623000	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	34442000	USD
	nfbk	Proceeds From Sale Of Equity Securities ProceedsFromSaleOfEquitySecurities	2035000	USD
	nfbk	Proceeds From Sale Of Equity Securities ProceedsFromSaleOfEquitySecurities	0	USD
	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	2716000	USD
	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	0	USD
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	1223000	USD
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	1637000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-25981000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-330657000	USD
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	213425000	USD
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	13679000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	10319000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	9925000	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	175000	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	1029000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	107000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	10065000	USD
	us-gaap	Allowance For Loan And Lease Losses Writeoffs Net AllowanceForLoanAndLeaseLossesWriteoffsNet	291000	USD
	us-gaap	Allowance For Loan And Lease Losses Writeoffs Net AllowanceForLoanAndLeaseLossesWriteoffsNet	215000	USD
	nfbk	Operating Lease Right Of Use Asset Initial Recognition Noncash OperatingLeaseRightOfUseAssetInitialRecognitionNoncash	0	USD
	nfbk	Operating Lease Right Of Use Asset Initial Recognition Noncash OperatingLeaseRightOfUseAssetInitialRecognitionNoncash	43560000	USD
	nfbk	Operating Lease Liability Initial Recognition Noncash OperatingLeaseLiabilityInitialRecognitionNoncash	0	USD
	us-gaap	Increase Decrease In Advance Payments By Borrowers For Taxes And Insurance IncreaseDecreaseInAdvancePaymentsByBorrowersForTaxesAndInsurance	-163000	USD
	us-gaap	Increase Decrease In Advance Payments By Borrowers For Taxes And Insurance IncreaseDecreaseInAdvancePaymentsByBorrowersForTaxesAndInsurance	2810000	USD
	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	0	USD
	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	44000	USD
	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	370267000	USD
	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	349760000	USD
	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	611000000	USD
	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	63502000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-37722000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	283742000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-36918000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-30855000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	147818000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	77762000	USD
CY2020Q2	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	110900000	USD
CY2019Q2	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	46907000	USD
	us-gaap	Interest Paid Net InterestPaidNet	24845000	USD
	nfbk	Operating Lease Liability Initial Recognition Noncash OperatingLeaseLiabilityInitialRecognitionNoncash	47328000	USD
CY2020Q2	us-gaap	Debt Securities Available For Sale Restricted DebtSecuritiesAvailableForSaleRestricted	584200000	USD
CY2020Q2	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	12600000	USD
CY2020Q2	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	74000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	9374000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	2992000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	1138352000	USD
	us-gaap	Transfer Of Portfolio Loans And Leases To Held For Sale1 TransferOfPortfolioLoansAndLeasesToHeldForSale1	47500000	USD
	us-gaap	Transfer Of Portfolio Loans And Leases To Held For Sale1 TransferOfPortfolioLoansAndLeasesToHeldForSale1	0	USD
CY2020Q2	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	1017254000	USD
CY2020Q2	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	20437000	USD
CY2020Q2	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	202000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	1037489000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	1131970000	USD
	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	214000	USD
CY2019Q2	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	59000	USD
CY2020Q2	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	1000	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	12600000	USD
	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	74000	USD
	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	14000	USD
CY2019Q2	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	5200000	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	34400000	USD
	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	0	USD
CY2019Q2	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	0	USD
CY2020Q2	us-gaap	Debt Securities Trading Realized Gain Loss DebtSecuritiesTradingRealizedGainLoss	1600000	USD
	us-gaap	Debt Securities Trading Realized Gain Loss DebtSecuritiesTradingRealizedGainLoss	-366000	USD
CY2019Q2	us-gaap	Debt Securities Trading Realized Gain Loss DebtSecuritiesTradingRealizedGainLoss	343000	USD
	us-gaap	Debt Securities Trading Realized Gain Loss DebtSecuritiesTradingRealizedGainLoss	1400000	USD
CY2020Q2	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	112000	USD
CY2020Q2	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	31892000	USD
CY2020Q2	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	90000	USD
	us-gaap	Other Than Temporary Impairment Loss Debt Securities Available For Sale Recognized In Earnings OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSaleRecognizedInEarnings	0	USD
CY2020Q2	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	13871000	USD
CY2020Q2	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	202000	USD
CY2020Q2	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	45763000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	975000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	201038000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	2017000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	125378000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	2992000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	326416000	USD
	us-gaap	Other Than Temporary Impairment Loss Debt Securities Available For Sale Recognized In Earnings OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSaleRecognizedInEarnings	0	USD
CY2020Q2	us-gaap	Other Than Temporary Impairment Loss Debt Securities Available For Sale Recognized In Earnings OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSaleRecognizedInEarnings	0	USD
CY2019Q2	us-gaap	Other Than Temporary Impairment Loss Debt Securities Available For Sale Recognized In Earnings OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSaleRecognizedInEarnings	0	USD
CY2020Q2	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	8648000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	370000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	0	USD
CY2020Q2	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	9018000	USD
CY2019Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	8762000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	129000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	5000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	8886000	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
CY2020Q2	us-gaap	Held To Maturity Securities Restricted HeldToMaturitySecuritiesRestricted	7300000	USD
CY2020Q2	nfbk	Debt Securities Held To Maturity Unrealized Loss Position Number Of Positions DebtSecuritiesHeldToMaturityUnrealizedLossPositionNumberOfPositions	0	security
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	0	USD
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	0	USD
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	5000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	378000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	5000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue	378000	USD
	us-gaap	Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net Heldtomaturity Securities OtherThanTemporaryImpairmentLossesInvestmentsPortionRecognizedInEarningsNetHeldtomaturitySecurities	0	USD
CY2019Q2	us-gaap	Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net Heldtomaturity Securities OtherThanTemporaryImpairmentLossesInvestmentsPortionRecognizedInEarningsNetHeldtomaturitySecurities	0	USD
	us-gaap	Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net Heldtomaturity Securities OtherThanTemporaryImpairmentLossesInvestmentsPortionRecognizedInEarningsNetHeldtomaturitySecurities	0	USD
CY2020Q2	us-gaap	Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net Heldtomaturity Securities OtherThanTemporaryImpairmentLossesInvestmentsPortionRecognizedInEarningsNetHeldtomaturitySecurities	0	USD
CY2020Q2	us-gaap	Equity Securities Fv Ni And Without Readily Determinable Fair Value EquitySecuritiesFvNiAndWithoutReadilyDeterminableFairValue	1300000	USD
CY2019Q4	us-gaap	Equity Securities Fv Ni And Without Readily Determinable Fair Value EquitySecuritiesFvNiAndWithoutReadilyDeterminableFairValue	3300000	USD
CY2020Q2	us-gaap	Notes Receivable Gross NotesReceivableGross	3589359000	USD
CY2019Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	3437085000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	38520000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	28707000	USD
CY2020Q2	us-gaap	Notes Receivable Net NotesReceivableNet	3550839000	USD
CY2019Q4	us-gaap	Notes Receivable Net NotesReceivableNet	3408378000	USD
CY2020Q2	us-gaap	Loans Receivable Held For Sale Amount LoansReceivableHeldForSaleAmount	0	USD
CY2019Q4	us-gaap	Loans Receivable Held For Sale Amount LoansReceivableHeldForSaleAmount	0	USD
CY2020Q1	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYield	16283000	USD
CY2019Q1	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYield	20797000	USD
CY2019Q4	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYield	17086000	USD
CY2018Q4	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYield	21846000	USD
CY2020Q2	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Accretion CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAccretion	717000	USD
CY2019Q2	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Accretion CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAccretion	1003000	USD
	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Accretion CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAccretion	1520000	USD
	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Accretion CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAccretion	2052000	USD
CY2020Q2	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYield	15566000	USD
CY2019Q2	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYield	19794000	USD
CY2020Q2	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYield	15566000	USD
CY2019Q2	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYield	19794000	USD
CY2020Q1	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	36800000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	221000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	20000	USD
CY2020Q2	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	1921000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	38520000	USD
CY2019Q1	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	27486000	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	233000	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	88000	USD
CY2019Q2	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	491000	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	27832000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	28707000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	691000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	400000	USD
	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	10104000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	38520000	USD
CY2018Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	27497000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	324000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	109000	USD
	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	550000	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	27832000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	319000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	38201000	USD
CY2020Q2	us-gaap	Notes Receivable Gross NotesReceivableGross	3589359000	USD
CY2020Q2	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	19881000	USD
CY2020Q2	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	3569478000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	142000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	28565000	USD
CY2019Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	3437085000	USD
CY2019Q4	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	20957000	USD
CY2019Q4	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	3416128000	USD
CY2020Q2	nfbk	Originated Loans Held For Investment Net OriginatedLoansHeldForInvestmentNet	3213689000	USD
CY2019Q4	nfbk	Originated Loans Held For Investment Net OriginatedLoansHeldForInvestmentNet	2987067000	USD
CY2020Q2	nfbk	Investment In Non Accrual Loans InvestmentInNonAccrualLoans	8800000	USD
CY2019Q4	nfbk	Investment In Non Accrual Loans InvestmentInNonAccrualLoans	9400000	USD
	nfbk	Delinquent Status Classification Criteria Days Minimum DelinquentStatusClassificationCriteriaDaysMinimum	P90D
	nfbk	Delinquent Status Classification Criteria Days Minimum DelinquentStatusClassificationCriteriaDaysMinimum	P90D
CY2020Q2	nfbk	Loans Deemed To Be Impaired Non Accrual Amount LoansDeemedToBeImpairedNonAccrualAmount	6600000	USD
CY2019Q4	nfbk	Loans Deemed To Be Impaired Non Accrual Amount LoansDeemedToBeImpairedNonAccrualAmount	6800000	USD
CY2020Q2	nfbk	Principal Balance Threshold For Non Accrual Status PrincipalBalanceThresholdForNonAccrualStatus	500000	USD
CY2020Q2	nfbk	Loans On Non Accrual Status With Principal Balances Below Threshold Definition Of Impaired Loan LoansOnNonAccrualStatusWithPrincipalBalancesBelowThresholdDefinitionOfImpairedLoan	2200000	USD
CY2019Q4	nfbk	Loans On Non Accrual Status With Principal Balances Below Threshold Definition Of Impaired Loan LoansOnNonAccrualStatusWithPrincipalBalancesBelowThresholdDefinitionOfImpairedLoan	2600000	USD
CY2020Q2	nfbk	Nonaccrual Loans Receivable Heldforsale Amount NonaccrualLoansReceivableHeldforsaleAmount	0	USD
CY2019Q4	nfbk	Nonaccrual Loans Receivable Heldforsale Amount NonaccrualLoansReceivableHeldforsaleAmount	0	USD
	nfbk	Delinquent Status Classification Criteria Days Minimum DelinquentStatusClassificationCriteriaDaysMinimum	P90D
CY2019	nfbk	Delinquent Status Classification Criteria Days Minimum DelinquentStatusClassificationCriteriaDaysMinimum	P90D
CY2020Q2	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	978000	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	518000	USD
	nfbk	Delinquent Status Classification Criteria Days Minimum DelinquentStatusClassificationCriteriaDaysMinimum	P90D
CY2019	nfbk	Delinquent Status Classification Criteria Days Minimum DelinquentStatusClassificationCriteriaDaysMinimum	P90D
CY2020Q2	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	19881000	USD
CY2020Q2	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	22304000	USD
CY2020Q2	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	319000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	20957000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	23132000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	142000	USD
CY2020Q2	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	12900000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	15900000	USD
CY2020Q2	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	20202000	USD
CY2020Q2	us-gaap	Impaired Financing Receivable Interest Income Cash Basis Method ImpairedFinancingReceivableInterestIncomeCashBasisMethod	277000	USD
CY2019Q2	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	21900000	USD
CY2019Q2	us-gaap	Impaired Financing Receivable Interest Income Cash Basis Method ImpairedFinancingReceivableInterestIncomeCashBasisMethod	206000	USD
	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	20451000	USD
	us-gaap	Impaired Financing Receivable Interest Income Cash Basis Method ImpairedFinancingReceivableInterestIncomeCashBasisMethod	436000	USD
	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	22042000	USD
	us-gaap	Impaired Financing Receivable Interest Income Cash Basis Method ImpairedFinancingReceivableInterestIncomeCashBasisMethod	416000	USD
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	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
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	2	contract
	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	2836000	USD
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	2836000	USD
CY2020Q2	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	4	contract
CY2020Q2	nfbk	Financing Receivable Modification Number Of Borrowers FinancingReceivableModificationNumberOfBorrowers	3	numberOfBorrowers
CY2020Q2	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	4	contract
CY2019Q2	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	0	contract
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	2	contract
CY2020Q2	nfbk	Trouble Debt Restructuring Amount TroubleDebtRestructuringAmount	17700000	USD
CY2019Q4	nfbk	Trouble Debt Restructuring Amount TroubleDebtRestructuringAmount	18500000	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
CY2020Q2	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	517441000	USD
CY2019Q4	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	387409000	USD
CY2020Q2	us-gaap	Deposits Negotiable Order Of Withdrawal Now DepositsNegotiableOrderOfWithdrawalNOW	685988000	USD
CY2019Q4	us-gaap	Deposits Negotiable Order Of Withdrawal Now DepositsNegotiableOrderOfWithdrawalNOW	573927000	USD
CY2020Q2	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	1483734000	USD
CY2019Q4	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	1398345000	USD
CY2020Q2	us-gaap	Time Deposits TimeDeposits	934495000	USD
CY2019Q4	us-gaap	Time Deposits TimeDeposits	1048552000	USD
CY2020Q2	us-gaap	Deposits Deposits	3621658000	USD
CY2019Q4	us-gaap	Deposits Deposits	3408233000	USD
CY2020Q2	us-gaap	Interest Expense Domestic Deposit Liabilities Demand InterestExpenseDomesticDepositLiabilitiesDemand	2894000	USD
CY2019Q2	us-gaap	Interest Expense Domestic Deposit Liabilities Demand InterestExpenseDomesticDepositLiabilitiesDemand	5377000	USD
	us-gaap	Interest Expense Domestic Deposit Liabilities Demand InterestExpenseDomesticDepositLiabilitiesDemand	6967000	USD
	us-gaap	Interest Expense Domestic Deposit Liabilities Demand InterestExpenseDomesticDepositLiabilitiesDemand	10171000	USD
CY2020Q2	us-gaap	Interest Expense Domestic Deposit Liabilities Certificates Of Deposit InterestExpenseDomesticDepositLiabilitiesCertificatesOfDeposit	4579000	USD
CY2019Q2	us-gaap	Interest Expense Domestic Deposit Liabilities Certificates Of Deposit InterestExpenseDomesticDepositLiabilitiesCertificatesOfDeposit	5172000	USD
	us-gaap	Interest Expense Domestic Deposit Liabilities Certificates Of Deposit InterestExpenseDomesticDepositLiabilitiesCertificatesOfDeposit	9785000	USD
	us-gaap	Interest Expense Domestic Deposit Liabilities Certificates Of Deposit InterestExpenseDomesticDepositLiabilitiesCertificatesOfDeposit	10625000	USD
CY2020Q2	us-gaap	Interest Expense Deposits InterestExpenseDeposits	7473000	USD
CY2019Q2	us-gaap	Interest Expense Deposits InterestExpenseDeposits	10549000	USD
	us-gaap	Interest Expense Deposits InterestExpenseDeposits	16752000	USD
	us-gaap	Interest Expense Deposits InterestExpenseDeposits	20796000	USD
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	2227193	shares
CY2019Q4	nfbk	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageGrantDateFairValue	4.01
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	13.93
CY2019	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P4Y11M15D
	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	13000	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	13.38
CY2020Q2	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	2214193	shares
CY2020Q2	nfbk	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageGrantDateFairValue	4.01
CY2020Q2	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	13.94
	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P4Y5M15D
CY2020Q2	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber	2189114	shares
CY2020Q2	nfbk	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageGrantDateFairValue	4.00
CY2020Q2	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice	13.91
	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P4Y5M12D
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Number ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber	71102	shares
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue	15.36
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod	103581	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	15.81
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod	58100	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	14.85
CY2020Q2	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Number ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber	116583	shares
CY2020Q2	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue	16.02
CY2020Q2	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	432000	USD
CY2019Q2	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	1100000	USD
	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	880000	USD
	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	2400000	USD
CY2020Q2	us-gaap	Loans Receivable Fair Value Disclosure LoansReceivableFairValueDisclosure	6706000	USD
CY2019Q4	us-gaap	Loans Receivable Fair Value Disclosure LoansReceivableFairValueDisclosure	4942000	USD
CY2020Q2	nfbk	Principal Amount Outstanding Of Impaired Loans Heldfor Investment Heldfor Sale PrincipalAmountOutstandingOfImpairedLoansHeldforInvestmentHeldforSale	9200000	USD
CY2019Q4	nfbk	Principal Amount Outstanding Of Impaired Loans Heldfor Investment Heldfor Sale PrincipalAmountOutstandingOfImpairedLoansHeldforInvestmentHeldforSale	7000000.0	USD
CY2020Q2	nfbk	Estimated Fair Value Of Impaired Loans Held For Investment EstimatedFairValueOfImpairedLoansHeldForInvestment	6700000	USD
CY2019Q4	nfbk	Estimated Fair Value Of Impaired Loans Held For Investment EstimatedFairValueOfImpairedLoansHeldForInvestment	4900000	USD
	us-gaap	Asset Impairment Charges AssetImpairmentCharges	177000	USD
	us-gaap	Asset Impairment Charges AssetImpairmentCharges	226000	USD
	nfbk	Impaired Financing Receivables Charge Off ImpairedFinancingReceivablesChargeOff	291000	USD
	nfbk	Impaired Financing Receivables Charge Off ImpairedFinancingReceivablesChargeOff	215000	USD
CY2020Q2	us-gaap	Equity Securities Without Readily Determinable Fair Value Amount EquitySecuritiesWithoutReadilyDeterminableFairValueAmount	1100000	USD
CY2019Q4	us-gaap	Equity Securities Without Readily Determinable Fair Value Amount EquitySecuritiesWithoutReadilyDeterminableFairValueAmount	3100000	USD
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	10793000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	8204000	USD
	us-gaap	Net Income Loss NetIncomeLoss	15344000	USD
	us-gaap	Net Income Loss NetIncomeLoss	16975000	USD
CY2020Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	46837473	shares
CY2019Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	46855647	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	46814647	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	46897546	shares
CY2020Q2	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	34017	shares
CY2019Q2	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	416043	shares
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	112857	shares
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	381650	shares
CY2020Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	46871490	shares
CY2019Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	47271690	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	46927504	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	47279196	shares
CY2020Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.23
CY2019Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.18
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.33
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.36
CY2020Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.23
CY2019Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.17
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.33
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.36
CY2020Q2	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	2316695	shares
CY2019Q2	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	848844	shares
	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	1659262	shares
	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	962296	shares
CY2020Q2	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	40400000	USD
CY2020Q2	us-gaap	Operating Lease Liability OperatingLeaseLiability	44800000	USD
CY2020Q2	us-gaap	Operating Lease Cost OperatingLeaseCost	1423000	USD
CY2019Q2	us-gaap	Operating Lease Cost OperatingLeaseCost	1551000	USD
	us-gaap	Operating Lease Cost OperatingLeaseCost	2862000	USD
	us-gaap	Operating Lease Cost OperatingLeaseCost	3017000	USD
CY2020Q2	us-gaap	Variable Lease Cost VariableLeaseCost	956000	USD
CY2019Q2	us-gaap	Variable Lease Cost VariableLeaseCost	711000	USD
	us-gaap	Variable Lease Cost VariableLeaseCost	1500000	USD
	us-gaap	Variable Lease Cost VariableLeaseCost	1489000	USD
CY2020Q2	us-gaap	Lease Cost LeaseCost	2379000	USD
CY2019Q2	us-gaap	Lease Cost LeaseCost	2262000	USD
	us-gaap	Lease Cost LeaseCost	4362000	USD
	us-gaap	Lease Cost LeaseCost	4506000	USD
CY2020Q2	us-gaap	Operating Lease Payments OperatingLeasePayments	0	USD
CY2019Q2	us-gaap	Operating Lease Payments OperatingLeasePayments	1513000	USD
	us-gaap	Operating Lease Payments OperatingLeasePayments	3069000	USD
	us-gaap	Operating Lease Payments OperatingLeasePayments	2840000	USD
CY2020Q2	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	0	USD
CY2019Q2	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	3028000	USD
	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	1013000	USD
CY2020Q2	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P12Y7M17D
CY2019Q2	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P12Y11M12D
CY2020Q2	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0359
CY2019Q2	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0361
CY2020Q2	us-gaap	Lessee Operating Lease Liability Payments Remainder Of Fiscal Year LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear	3157000	USD
CY2020Q2	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	5919000	USD
CY2020Q2	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	5311000	USD
CY2020Q2	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	5272000	USD
CY2020Q2	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	4935000	USD
CY2020Q2	nfbk	Lessee Operating Lease Liability Payments Due After Year Four LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFour	33230000	USD
CY2020Q2	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	57824000	USD
CY2020Q2	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	13043000	USD
CY2020Q2	us-gaap	Operating Lease Liability OperatingLeaseLiability	44781000	USD
CY2020Q2	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	666000	USD
CY2019Q2	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	1207000	USD
	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	1786000	USD
	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	2347000	USD
CY2020Q2	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	865000	USD
CY2019Q2	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	907000	USD
	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	1741000	USD
	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	1804000	USD
CY2020Q2	us-gaap	Debt Securities Available For Sale Gain Loss DebtSecuritiesAvailableForSaleGainLoss	73000	USD
CY2019Q2	us-gaap	Debt Securities Available For Sale Gain Loss DebtSecuritiesAvailableForSaleGainLoss	59000	USD
	us-gaap	Debt Securities Available For Sale Gain Loss DebtSecuritiesAvailableForSaleGainLoss	60000	USD
	us-gaap	Debt Securities Available For Sale Gain Loss DebtSecuritiesAvailableForSaleGainLoss	214000	USD
CY2020Q2	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	1626000	USD
CY2019Q2	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	343000	USD
	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	-366000	USD
	us-gaap	Debt And Equity Securities Gain Loss DebtAndEquitySecuritiesGainLoss	1429000	USD
CY2020Q2	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	665000	USD
CY2019Q2	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	0	USD
	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	665000	USD
	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	0	USD
CY2020Q2	us-gaap	Derivative Gain Loss On Derivative Net DerivativeGainLossOnDerivativeNet	308000	USD
CY2019Q2	us-gaap	Derivative Gain Loss On Derivative Net DerivativeGainLossOnDerivativeNet	0	USD
	us-gaap	Derivative Gain Loss On Derivative Net DerivativeGainLossOnDerivativeNet	384000	USD
	us-gaap	Derivative Gain Loss On Derivative Net DerivativeGainLossOnDerivativeNet	0	USD
CY2020Q2	us-gaap	Revenue Not From Contract With Customer Other RevenueNotFromContractWithCustomerOther	35000	USD
CY2019Q2	us-gaap	Revenue Not From Contract With Customer Other RevenueNotFromContractWithCustomerOther	50000	USD
	us-gaap	Revenue Not From Contract With Customer Other RevenueNotFromContractWithCustomerOther	76000	USD
	us-gaap	Revenue Not From Contract With Customer Other RevenueNotFromContractWithCustomerOther	86000	USD
CY2020Q2	us-gaap	Noninterest Income NoninterestIncome	4238000	USD
CY2019Q2	us-gaap	Noninterest Income NoninterestIncome	2566000	USD
	us-gaap	Noninterest Income NoninterestIncome	4346000	USD
	us-gaap	Noninterest Income NoninterestIncome	5880000	USD
CY2020Q2	us-gaap	Derivative Gain Loss On Derivative Net DerivativeGainLossOnDerivativeNet	308000	USD
	us-gaap	Derivative Gain Loss On Derivative Net DerivativeGainLossOnDerivativeNet	384000	USD
CY2020Q1	us-gaap	Reporting Unit Percentage Of Fair Value In Excess Of Carrying Amount ReportingUnitPercentageOfFairValueInExcessOfCarryingAmount	0.27

Files In Submission

Name	View Source	Status
0001493225-20-000104-index-headers.html	Edgar Link	pending
0001493225-20-000104-index.html	Edgar Link	pending
0001493225-20-000104.txt	Edgar Link	pending
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$NFBK
Northfield Bancorp, Inc. Stock $nfbk

2020 Q2 Form 10-Q Financial Statement

#000149322520000104 Filed on August 10, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$NFBK Northfield Bancorp, Inc. Stock $nfbk

2020 Q2 Form 10-Q Financial Statement

#000149322520000104 Filed on August 10, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$NFBK
Northfield Bancorp, Inc. Stock $nfbk