$NBBK
NB Bancorp, Inc. Stock $nbbk

$nbbk Overview Financials Valuation SEC Filings Company Website

2024 Q3 Form 10-Q Financial Statement

#000155837024011709 Filed on August 09, 2024

Income Statement

Concept	2024 Q3	2024 Q2	2023 Q2
Revenue	$76.00M	$71.39M	$52.91M
YoY Change	28.27%	34.93%
Cost Of Revenue
YoY Change
Gross Profit
YoY Change
Gross Profit Margin
Selling, General & Admin	$20.15M	$21.80M	$18.15M
YoY Change	10.51%	20.06%
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$707.0K	$707.0K	$1.332M
YoY Change	4.9%	-46.92%
% of Gross Profit
Operating Expenses	$23.64M	$26.53M	$23.01M
YoY Change	10.95%	15.32%
Operating Profit
YoY Change
Interest Expense	-$34.68M	-$32.40M	-$20.51M
YoY Change	-232.8%	57.99%
% of Operating Profit
Other Income/Expense, Net	-$812.0K	-$633.0K	-$937.0K
YoY Change	-33.17%	-32.44%
Pretax Income	$15.38M	$11.82M	$8.455M
YoY Change	32.94%	39.82%
Income Tax	$6.997M	$2.369M	$2.230M
% Of Pretax Income	45.49%	20.04%	26.37%
Net Earnings	$8.383M	$9.453M	$6.225M
YoY Change	-0.99%	51.86%	-6.64%
Net Earnings / Revenue	11.03%	13.24%	11.77%
Basic Earnings Per Share	$0.21	$0.24
Diluted Earnings Per Share	$0.21	$0.24	$0.15
COMMON SHARES
Basic Shares Outstanding	42.71M	42.71M
Diluted Shares Outstanding	39.29M	39.29M

Balance Sheet

Concept	2024 Q3	2024 Q2	2023 Q2
SHORT-TERM ASSETS
Cash & Short-Term Investments	$148.2M	$170.3M	$81.86M
YoY Change	44.64%	107.98%
Cash & Equivalents	$317.0M	$170.3M	$81.86M
Short-Term Investments
Other Short-Term Assets
YoY Change
Inventory
Prepaid Expenses
Receivables
Other Receivables
Total Short-Term Assets	$166.9M	$189.3M	$94.62M
YoY Change	41.05%	100.01%
LONG-TERM ASSETS
Property, Plant & Equipment	$34.80M	$35.29M	$35.98M
YoY Change	-3.23%	-1.92%
Goodwill
YoY Change
Intangibles
YoY Change
Long-Term Investments	$395.7M	$395.9M	$283.3M
YoY Change	48.69%	39.74%
Other Assets	$17.47M	$18.87M	$8.868M
YoY Change	118.62%	112.81%
Total Long-Term Assets	$4.836B	$4.616B	$3.934B
YoY Change	17.56%	17.34%
TOTAL ASSETS
Total Short-Term Assets	$166.9M	$189.3M	$94.62M
Total Long-Term Assets	$4.836B	$4.616B	$3.934B
Total Assets	$5.003B	$4.805B	$4.029B
YoY Change	18.21%	19.28%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable
YoY Change
Accrued Expenses	$91.56M	$78.18M	$68.60M
YoY Change	14.67%	13.97%
Deferred Revenue
YoY Change
Short-Term Debt	$4.043B	$3.918B	$3.262B
YoY Change	17.64%	20.12%
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$4.134B	$3.996B	$3.330B
YoY Change	17.57%	19.99%
LONG-TERM LIABILITIES
Long-Term Debt	$116.3M	$60.84M	$337.6M
YoY Change	-66.34%	-81.98%
Other Long-Term Liabilities	$4.401M	$4.022M	$3.741M
YoY Change	11.33%	7.51%
Total Long-Term Liabilities	$120.7M	$64.86M	$341.4M
YoY Change	-65.46%	-81.0%
TOTAL LIABILITIES
Total Short-Term Liabilities	$4.134B	$3.996B	$3.330B
Total Long-Term Liabilities	$120.7M	$64.86M	$341.4M
Total Liabilities	$4.255B	$4.061B	$3.672B
YoY Change	10.06%	10.6%
SHAREHOLDERS EQUITY
Retained Earnings	$382.6M	$384.3M
YoY Change	0.73%
Common Stock	$427.0K	$427.0K
YoY Change
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$747.4M	$744.5M	$357.0M
YoY Change
Total Liabilities & Shareholders Equity	$5.003B	$4.805B	$4.029B
YoY Change	18.21%	19.28%

Cashflow Statement

Concept	2024 Q3	2024 Q2	2023 Q2
OPERATING ACTIVITIES
Net Income	$8.383M	$9.453M	$6.225M
YoY Change	-0.99%	51.86%	-6.64%
Depreciation, Depletion And Amortization	$707.0K	$707.0K	$1.332M
YoY Change	4.9%	-46.92%
Cash From Operating Activities	$9.617M	$24.73M	$23.28M
YoY Change	-41.36%	6.24%
INVESTING ACTIVITIES
Capital Expenditures	$219.0K	$891.0K	$1.970M
YoY Change	-66.62%	-54.77%
Acquisitions
YoY Change
Other Investing Activities	-$202.1M	-$155.5M	-$483.5M
YoY Change	13.13%	-67.84%
Cash From Investing Activities	-$202.3M	-$156.4M	-$485.5M
YoY Change	12.84%	-67.78%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	180.8M	145.6M	419.2M
YoY Change	-1.31%	-65.27%
NET CHANGE
Cash From Operating Activities	9.617M	24.73M	23.28M
Cash From Investing Activities	-202.3M	-156.4M	-485.5M
Cash From Financing Activities	180.8M	145.6M	419.2M
Net Change In Cash	-11.89M	13.91M	-43.03M
YoY Change	-158.55%	-132.33%
FREE CASH FLOW
Cash From Operating Activities	$9.617M	$24.73M	$23.28M
Capital Expenditures	$219.0K	$891.0K	$1.970M
Free Cash Flow	$9.398M	$23.84M	$21.31M
YoY Change	-40.31%	11.88%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value
	dei	Entity Central Index Key EntityCentralIndexKey	0001979330
	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2024
	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	Q2
	dei	Amendment Flag AmendmentFlag	false
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	dei	Document Type DocumentType	10-Q
	dei	Document Quarterly Report DocumentQuarterlyReport	true
	dei	Document Period End Date DocumentPeriodEndDate	2024-06-30
	dei	Document Transition Report DocumentTransitionReport	false
	dei	Entity File Number EntityFileNumber	001-41899
	dei	Entity Registrant Name EntityRegistrantName	NB Bancorp, Inc.
	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	MD
	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	93-2560883
	dei	Entity Address Address Line1 EntityAddressAddressLine1	1063 Great Plain Avenue
	dei	Entity Address City Or Town EntityAddressCityOrTown	Needham
	dei	Entity Address State Or Province EntityAddressStateOrProvince	MA
	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	02492
	dei	City Area Code CityAreaCode	781
	dei	Local Phone Number LocalPhoneNumber	444-2100
	dei	Security12b Title Security12bTitle	Common stock, par value $0.01 per share
	dei	Trading Symbol TradingSymbol	NBBK
	dei	Security Exchange Name SecurityExchangeName	NASDAQ
	dei	Entity Filer Category EntityFilerCategory	Non-accelerated Filer
	dei	Entity Small Business EntitySmallBusiness	false
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CY2023Q2	nbbk	Noninterest Expense Directors And Professional Fees NoninterestExpenseDirectorsAndProfessionalFees	1712000
	nbbk	Noninterest Expense Directors And Professional Fees NoninterestExpenseDirectorsAndProfessionalFees	4178000
	nbbk	Noninterest Expense Directors And Professional Fees NoninterestExpenseDirectorsAndProfessionalFees	3376000
CY2024Q2	nbbk	Occupancy And Equipment Expenses OccupancyAndEquipmentExpenses	1461000
CY2023Q2	nbbk	Occupancy And Equipment Expenses OccupancyAndEquipmentExpenses	1272000
	nbbk	Occupancy And Equipment Expenses OccupancyAndEquipmentExpenses	2797000
	nbbk	Occupancy And Equipment Expenses OccupancyAndEquipmentExpenses	2647000
CY2024Q2	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	2325000
CY2023Q2	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	1722000
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	4320000
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	3439000
CY2024Q2	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	1095000
CY2023Q2	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	864000
	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	1837000
	us-gaap	Marketing And Advertising Expense MarketingAndAdvertisingExpense	2054000
CY2024Q2	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	633000
CY2023Q2	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	937000
	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	994000
	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	1629000
CY2024Q2	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	1684000
CY2023Q2	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	1432000
	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	3348000
	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	2850000
CY2024Q2	us-gaap	Noninterest Expense NoninterestExpense	26214000
CY2023Q2	us-gaap	Noninterest Expense NoninterestExpense	22337000
	us-gaap	Noninterest Expense NoninterestExpense	51781000
	us-gaap	Noninterest Expense NoninterestExpense	45370000
CY2024Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	11822000
CY2023Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	8455000
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	23962000
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	20436000
CY2024Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	2369000
CY2023Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	2230000
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	5808000
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	5459000
CY2024Q2	us-gaap	Net Income Loss NetIncomeLoss	9453000
CY2023Q2	us-gaap	Net Income Loss NetIncomeLoss	6225000
	us-gaap	Net Income Loss NetIncomeLoss	18154000
	us-gaap	Net Income Loss NetIncomeLoss	14977000
CY2024Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	39289271
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	39490552
CY2024Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	39289271
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	39490552
CY2024Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.24
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.46
CY2024Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.24
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.46
CY2024Q2	us-gaap	Net Income Loss NetIncomeLoss	9453000
CY2023Q2	us-gaap	Net Income Loss NetIncomeLoss	6225000
	us-gaap	Net Income Loss NetIncomeLoss	18154000
	us-gaap	Net Income Loss NetIncomeLoss	14977000
CY2024Q2	us-gaap	Other Comprehensive Income Availableforsale Securities Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent	550000
CY2023Q2	us-gaap	Other Comprehensive Income Availableforsale Securities Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent	-1003000
	us-gaap	Other Comprehensive Income Availableforsale Securities Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent	762000
	us-gaap	Other Comprehensive Income Availableforsale Securities Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent	280000
CY2023Q2	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent	-36000
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent	-231000
CY2024Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	550000
CY2023Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-1039000
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	762000
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	49000
CY2024Q2	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	10003000
CY2023Q2	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	5186000
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	18916000
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	15026000
CY2023Q1	us-gaap	Stockholders Equity StockholdersEquity	351787000
CY2023Q2	us-gaap	Net Income Loss NetIncomeLoss	6225000
CY2023Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-1039000
CY2023Q2	us-gaap	Stockholders Equity StockholdersEquity	356973000
CY2024Q1	us-gaap	Stockholders Equity StockholdersEquity	733838000
CY2024Q2	us-gaap	Net Income Loss NetIncomeLoss	9453000
CY2024Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	550000
CY2024Q2	us-gaap	Employee Stock Ownership Plan Esop Shares Contributed To Esop EmployeeStockOwnershipPlanESOPSharesContributedToESOP	42589
CY2024Q2	us-gaap	Amortization Of Esop Award AmortizationOfESOPAward	621000
CY2024Q2	us-gaap	Stockholders Equity StockholdersEquity	744462000
CY2022Q4	us-gaap	Stockholders Equity StockholdersEquity	344065000
	us-gaap	Net Income Loss NetIncomeLoss	14977000
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	49000
CY2023Q2	us-gaap	Stockholders Equity StockholdersEquity	356973000
CY2023Q4	us-gaap	Stockholders Equity StockholdersEquity	757959000
	us-gaap	Net Income Loss NetIncomeLoss	18154000
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	762000
	us-gaap	Adjustments To Additional Paid In Capital Stock Issued Issuance Costs AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts	225000
	nbbk	Shares Puchase By Employee Stock Ownership Plan Shares SharesPuchaseByEmployeeStockOwnershipPlanShares	2416458
	nbbk	Shares Purchase By Employee Stock Ownership Plan Value SharesPurchaseByEmployeeStockOwnershipPlanValue	33397000
	us-gaap	Employee Stock Ownership Plan Esop Shares Contributed To Esop EmployeeStockOwnershipPlanESOPSharesContributedToESOP	84709
	us-gaap	Amortization Of Esop Award AmortizationOfESOPAward	1209000
CY2024Q2	us-gaap	Stockholders Equity StockholdersEquity	744462000
	us-gaap	Profit Loss ProfitLoss	18154000
	us-gaap	Profit Loss ProfitLoss	14977000
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	138000
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	230000
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	74000
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	74000
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	8096000
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	6116000
	nbbk	Fair Value Adjustments Of Loan Hedged Including Amortization FairValueAdjustmentsOfLoanHedgedIncludingAmortization	55000
	nbbk	Fair Value Adjustments Of Loan Hedged Including Amortization FairValueAdjustmentsOfLoanHedgedIncludingAmortization	79000
	us-gaap	Amortization Of Deferred Loan Origination Fees Net AmortizationOfDeferredLoanOriginationFeesNet	-102000
	us-gaap	Amortization Of Deferred Loan Origination Fees Net AmortizationOfDeferredLoanOriginationFeesNet	-2878000
	us-gaap	Payments For Origination Of Mortgage Loans Held For Sale PaymentsForOriginationOfMortgageLoansHeldForSale	2759000
	us-gaap	Payments For Origination Of Mortgage Loans Held For Sale PaymentsForOriginationOfMortgageLoansHeldForSale	1937000
	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	14102000
	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	1943000
	us-gaap	Gain Loss On Sale Of Mortgage Loans GainLossOnSaleOfMortgageLoans	161000
	us-gaap	Gain Loss On Sale Of Mortgage Loans GainLossOnSaleOfMortgageLoans	6000
	us-gaap	Other Depreciation And Amortization OtherDepreciationAndAmortization	1402000
	us-gaap	Other Depreciation And Amortization OtherDepreciationAndAmortization	1332000
	us-gaap	Life Insurance Corporate Or Bank Owned Change In Value LifeInsuranceCorporateOrBankOwnedChangeInValue	805000
	us-gaap	Life Insurance Corporate Or Bank Owned Change In Value LifeInsuranceCorporateOrBankOwnedChangeInValue	743000
	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	-20000
	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	-22000
	us-gaap	Employee Stock Ownership Plan Esop Compensation Expense EmployeeStockOwnershipPlanESOPCompensationExpense	1209000
	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	1723000
	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	1926000
	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	2295000
	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	4576000
	us-gaap	Increase Decrease In Income Taxes Receivable IncreaseDecreaseInIncomeTaxesReceivable	-3483000
	us-gaap	Increase Decrease In Accrued Liabilities And Other Operating Liabilities IncreaseDecreaseInAccruedLiabilitiesAndOtherOperatingLiabilities	-23004000
	us-gaap	Increase Decrease In Accrued Liabilities And Other Operating Liabilities IncreaseDecreaseInAccruedLiabilitiesAndOtherOperatingLiabilities	727000
	nbbk	Increase Decrease In Accrued Retirement Liabilities IncreaseDecreaseInAccruedRetirementLiabilities	866000
	nbbk	Increase Decrease In Accrued Retirement Liabilities IncreaseDecreaseInAccruedRetirementLiabilities	1113000
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	13155000
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	23282000
	nbbk	Proceeds From Loan Originations Net Of Repayments ProceedsFromLoanOriginationsNetOfRepayments	222227000
	nbbk	Proceeds From Loan Originations Net Of Repayments ProceedsFromLoanOriginationsNetOfRepayments	510296000
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	35860000
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	26725000
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	21434000
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	58808000
	us-gaap	Payments For Proceeds From Federal Home Loan Bank Stock PaymentsForProceedsFromFederalHomeLoanBankStock	-9791000
	us-gaap	Payments For Proceeds From Federal Home Loan Bank Stock PaymentsForProceedsFromFederalHomeLoanBankStock	3403000
	us-gaap	Payments For Proceeds From Federal Reserve Bank Stock PaymentsForProceedsFromFederalReserveBankStock	1010000
	us-gaap	Payments For Proceeds From Federal Reserve Bank Stock PaymentsForProceedsFromFederalReserveBankStock	1331000
	us-gaap	Proceeds From Recoveries Of Loan Previously Charged Off ProceedsFromRecoveriesOfLoanPreviouslyChargedOff	205000
	us-gaap	Proceeds From Recoveries Of Loan Previously Charged Off ProceedsFromRecoveriesOfLoanPreviouslyChargedOff	526000
	nbbk	Payments For Proceeds From Non Public Investments PaymentsForProceedsFromNonPublicInvestments	-2201000
	nbbk	Payments For Proceeds From Non Public Investments PaymentsForProceedsFromNonPublicInvestments	-1076000
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	1161000
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	1970000
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-231029000
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-485467000
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	530557000
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	374928000
	us-gaap	Payments Of Stock Issuance Costs PaymentsOfStockIssuanceCosts	225000
	us-gaap	Origination Of Loans To Employee Stock Ownership Plans OriginationOfLoansToEmployeeStockOwnershipPlans	33397000
	us-gaap	Increase Decrease In Advance Payments By Borrowers For Taxes And Insurance IncreaseDecreaseInAdvancePaymentsByBorrowersForTaxesAndInsurance	-207000
	us-gaap	Increase Decrease In Advance Payments By Borrowers For Taxes And Insurance IncreaseDecreaseInAdvancePaymentsByBorrowersForTaxesAndInsurance	-323000
	us-gaap	Increase Decrease In Loans From Other Federal Home Loan Banks IncreaseDecreaseInLoansFromOtherFederalHomeLoanBanks	-222503000
	us-gaap	Increase Decrease In Loans From Other Federal Home Loan Banks IncreaseDecreaseInLoansFromOtherFederalHomeLoanBanks	44555000
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	274225000
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	419160000
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect	56351000
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect	-43025000
CY2023Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	272591000
CY2022Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	156545000
CY2024Q2	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	328942000
CY2023Q2	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	113520000
	us-gaap	Interest Paid Net InterestPaidNet	58913000
	us-gaap	Interest Paid Net InterestPaidNet	33716000
	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	11092000
	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	1995000
	nbbk	Noncash Cumulative Effect Adjustment Due To Adoption Of Net Of Income Taxes NoncashCumulativeEffectAdjustmentDueToAdoptionOfNetOfIncomeTaxes	2118000
	us-gaap	Debt Securities Available For Sale Unrealized Gain Loss DebtSecuritiesAvailableForSaleUnrealizedGainLoss	1036000
	us-gaap	Debt Securities Available For Sale Unrealized Gain Loss DebtSecuritiesAvailableForSaleUnrealizedGainLoss	350000
	us-gaap	Unrealized Gain Loss On Cash Flow Hedging Instruments UnrealizedGainLossOnCashFlowHedgingInstruments	-321000
	us-gaap	Transfer Of Portfolio Loans And Leases To Held For Sale1 TransferOfPortfolioLoansAndLeasesToHeldForSale1	11182000
CY2023Q4	nbbk	Stock Issued During Period Issued Charity Shares New Issues StockIssuedDuringPeriodIssuedCharitySharesNewIssues	1708229
CY2023Q4	nbbk	Amount Donated To Charitable Foundation AmountDonatedToCharitableFoundation	2000000.0
CY2024Q2	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss	218833000
CY2024Q2	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	16000
CY2024Q2	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	13784000
CY2024Q2	us-gaap	Debt Securities Available For Sale Amortized Cost Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest	0
CY2024Q2	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	205065000
CY2023Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss	204269000
CY2023Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	37000
CY2023Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	14841000
CY2023Q4	us-gaap	Debt Securities Available For Sale Amortized Cost Allowance For Credit Loss Excluding Accrued Interest DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest	0
CY2023Q4	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	189465000
CY2024Q2	us-gaap	Debt Securities Available For Sale Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLoss	1500000
	us-gaap	Financing Receivable Accrued Interest Writeoff FinancingReceivableAccruedInterestWriteoff	0
CY2024Q2	nbbk	Debt Securities Available For Sale Delinquent Amount At End Of Period DebtSecuritiesAvailableForSaleDelinquentAmountAtEndOfPeriod	0
CY2024Q2	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	0
CY2024Q2	us-gaap	Available For Sale Securities Debt Maturities Within One Year Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost	66063000
CY2024Q2	us-gaap	Available For Sale Securities Debt Maturities Within One Year Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue	65763000
CY2024Q2	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost	100023000
CY2024Q2	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	94168000
CY2024Q2	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost	37491000
CY2024Q2	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	32375000
CY2024Q2	us-gaap	Available For Sale Securities Debt Maturities Single Maturity Date Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis	203577000
CY2024Q2	us-gaap	Available For Sale Securities Debt Maturities Single Maturity Date AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate	192306000
CY2024Q2	us-gaap	Debt Securities Available For Sale Amortized Cost Excluding Accrued Interest Before Allowance For Credit Loss DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss	218833000
CY2024Q2	us-gaap	Debt Securities Available For Sale Excluding Accrued Interest DebtSecuritiesAvailableForSaleExcludingAccruedInterest	205065000
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	0
CY2023Q2	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	0
	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	0
CY2024Q2	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	0
CY2024Q2	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Number Of Positions DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions	83
CY2024Q2	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	1406000
CY2024Q2	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	43527000
CY2024Q2	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	12378000
CY2024Q2	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	135282000
CY2024Q2	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	13784000
CY2024Q2	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	178809000
CY2023Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Number Of Positions DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions	84
CY2023Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	1411000
CY2023Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	16569000
CY2023Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	13430000
CY2023Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	155633000
CY2023Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	14841000
CY2023Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	172202000
	nbbk	Available For Sale Securities In Unrealized Loss Positions Qualitative Disclosure Rate Of Depreciation AvailableForSaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureRateOfDepreciation	0.084
CY2024Q2	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss DebtSecuritiesAvailableForSaleAllowanceForCreditLoss	0
CY2024Q2	nbbk	Financing Receivable Excluding Accrued Interest Allowance For Credit Losses Individually Evaluated For Impairment Threshold Amount FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossesIndividuallyEvaluatedForImpairmentThresholdAmount	500000
	nbbk	Financing Receivable Non Accrual Loans Percentage Excluded From Individually Evaluated Loans FinancingReceivableNonAccrualLoansPercentageExcludedFromIndividuallyEvaluatedLoans	0.75
CY2024Q2	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss Fee And Loan In Process FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLossFeeAndLoanInProcess	4102310000
CY2024Q2	srt	Financing Receivable Before Allowance For Credit Loss To Total Percent FinancingReceivableBeforeAllowanceForCreditLossToTotalPercent	1.0000
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss Fee And Loan In Process FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLossFeeAndLoanInProcess	3894209000
CY2023Q4	srt	Financing Receivable Before Allowance For Credit Loss To Total Percent FinancingReceivableBeforeAllowanceForCreditLossToTotalPercent	1.0000
CY2024Q2	us-gaap	Financing Receivable Unamortized Loan Fee Cost FinancingReceivableUnamortizedLoanFeeCost	-5032000
CY2023Q4	us-gaap	Financing Receivable Unamortized Loan Fee Cost FinancingReceivableUnamortizedLoanFeeCost	-4930000
CY2024Q2	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	37857000
CY2023Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	32222000
CY2024Q2	us-gaap	Financing Receivable Excluding Accrued Interest After Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss	4059421000
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest After Allowance For Credit Loss FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss	3857057000
CY2024Q2	us-gaap	Financing Receivable Excluding Accrued Interest Nonaccrual FinancingReceivableExcludingAccruedInterestNonaccrual	20728000
CY2024Q2	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss Fee And Loan In Process FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLossFeeAndLoanInProcess	4102310000
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Nonaccrual FinancingReceivableExcludingAccruedInterestNonaccrual	10798000
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss Fee And Loan In Process FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLossFeeAndLoanInProcess	3894209000
CY2024Q2	us-gaap	Financing Receivable Excluding Accrued Interest Nonaccrual No Allowance FinancingReceivableExcludingAccruedInterestNonaccrualNoAllowance	10803000
CY2024Q2	nbbk	Financing Receivable Excluding Accrued Interest Nonaccrual With Related Allowance FinancingReceivableExcludingAccruedInterestNonaccrualWithRelatedAllowance	9925000
CY2024Q2	us-gaap	Financing Receivable Excluding Accrued Interest Nonaccrual FinancingReceivableExcludingAccruedInterestNonaccrual	20728000
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Nonaccrual No Allowance FinancingReceivableExcludingAccruedInterestNonaccrualNoAllowance	7036000
CY2023Q4	nbbk	Financing Receivable Excluding Accrued Interest Nonaccrual With Related Allowance FinancingReceivableExcludingAccruedInterestNonaccrualWithRelatedAllowance	3762000
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Nonaccrual FinancingReceivableExcludingAccruedInterestNonaccrual	10798000
	nbbk	Reversal Amount Of Interest Income For Loans On Non Accrual ReversalAmountOfInterestIncomeForLoansOnNonAccrual	149000
CY2024Q2	nbbk	Reversal Amount Of Interest Income For Loans On Non Accrual ReversalAmountOfInterestIncomeForLoansOnNonAccrual	149000
	nbbk	Reversal Amount Of Interest Income For Loans On Non Accrual ReversalAmountOfInterestIncomeForLoansOnNonAccrual	0
CY2023Q2	nbbk	Reversal Amount Of Interest Income For Loans On Non Accrual ReversalAmountOfInterestIncomeForLoansOnNonAccrual	0
	nbbk	Financing Receivable Non Accrual Loans Percentage Excluded From Individually Evaluated Loans FinancingReceivableNonAccrualLoansPercentageExcludedFromIndividuallyEvaluatedLoans	0.75
CY2024Q2	us-gaap	Financing Receivable Excluding Accrued Interest Year One Originated Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear	198583000
CY2024Q2	us-gaap	Financing Receivable Excluding Accrued Interest Year Two Originated Fiscal Year Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear	859713000
CY2024Q2	us-gaap	Financing Receivable Excluding Accrued Interest Year Three Originated Two Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear	1087866000
CY2024Q2	us-gaap	Financing Receivable Excluding Accrued Interest Year Four Originated Three Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear	511708000
CY2024Q2	us-gaap	Financing Receivable Excluding Accrued Interest Year Five Originated Four Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear	288002000
CY2024Q2	us-gaap	Financing Receivable Excluding Accrued Interest Originated More Than Five Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear	609709000
CY2024Q2	us-gaap	Financing Receivable Excluding Accrued Interest Revolving FinancingReceivableExcludingAccruedInterestRevolving	546729000
CY2024Q2	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss Fee And Loan In Process FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLossFeeAndLoanInProcess	4102310000
CY2024Q2	us-gaap	Financing Receivable Excluding Accrued Interest Year Two Originated Fiscal Year Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff	87000
CY2024Q2	us-gaap	Financing Receivable Excluding Accrued Interest Year Three Originated Two Years Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff	319000
CY2024Q2	us-gaap	Financing Receivable Excluding Accrued Interest Year Four Originated Three Years Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff	495000
CY2024Q2	us-gaap	Financing Receivable Excluding Accrued Interest Year Five Originated Four Years Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff	39000
CY2024Q2	us-gaap	Financing Receivable Excluding Accrued Interest Originated More Than Five Years Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearWriteoff	1000
CY2024Q2	us-gaap	Financing Receivable Excluding Accrued Interest Revolving Writeoff FinancingReceivableExcludingAccruedInterestRevolvingWriteoff	5000
CY2024Q2	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff	946000
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year One Originated Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear	793754000
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Two Originated Fiscal Year Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear	1171429000
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Three Originated Two Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear	565913000
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Four Originated Three Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear	291478000
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Year Five Originated Four Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear	251400000
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Originated More Than Five Years Before Current Fiscal Year FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear	390106000
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Revolving FinancingReceivableExcludingAccruedInterestRevolving	430129000
CY2023Q4	us-gaap	Financing Receivable Excluding Accrued Interest Before Allowance For Credit Loss Fee And Loan In Process FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLossFeeAndLoanInProcess	3894209000
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Year One Originated Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearWriteoff	42000
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Year Two Originated Fiscal Year Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff	572000
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Year Three Originated Two Years Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff	585000
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Year Four Originated Three Years Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff	228000
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Year Five Originated Four Years Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff	72000
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Originated More Than Five Years Before Current Fiscal Year Writeoff FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearWriteoff	18000
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Revolving Writeoff FinancingReceivableExcludingAccruedInterestRevolvingWriteoff	1000
CY2023	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff	1518000
CY2024Q1	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	34306000
CY2024Q2	us-gaap	Financing Receivable Excluding Accrued Interest Credit Loss Expense Reversal FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal	4429000
CY2024Q2	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff	946000
CY2024Q2	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Recovery FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRecovery	68000
CY2024Q2	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	37857000
CY2023Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	32222000
	us-gaap	Financing Receivable Excluding Accrued Interest Credit Loss Expense Reversal FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal	8319000
	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff	2889000
	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Recovery FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRecovery	205000
CY2024Q2	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	37857000
CY2023Q1	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	27931000
CY2023Q2	us-gaap	Financing Receivable Excluding Accrued Interest Credit Loss Expense Reversal FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal	3958000
CY2023Q2	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff	633000
CY2023Q2	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Recovery FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRecovery	217000
CY2023Q2	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	31473000
CY2022Q4	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	25028000
	us-gaap	Financing Receivable Excluding Accrued Interest Credit Loss Expense Reversal FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal	6030000
	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Writeoff FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff	1270000
	us-gaap	Financing Receivable Excluding Accrued Interest Allowance For Credit Loss Recovery FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRecovery	526000
CY2023Q2	us-gaap	Financing Receivable Allowance For Credit Loss Excluding Accrued Interest FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest	31473000
CY2024Q2	nbbk	Financing Receivable Excluding Accrued Interest Collateral Dependent Loan Amount FinancingReceivableExcludingAccruedInterestCollateralDependentLoanAmount	19050000
CY2023Q4	nbbk	Financing Receivable Excluding Accrued Interest Collateral Dependent Loan Amount FinancingReceivableExcludingAccruedInterestCollateralDependentLoanAmount	9430000
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	0
CY2023Q2	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	0
CY2024Q2	us-gaap	Defined Contribution Plan Employer Discretionary Contribution Amount DefinedContributionPlanEmployerDiscretionaryContributionAmount	726000
CY2023Q2	us-gaap	Defined Contribution Plan Employer Discretionary Contribution Amount DefinedContributionPlanEmployerDiscretionaryContributionAmount	476000
	us-gaap	Defined Contribution Plan Employer Discretionary Contribution Amount DefinedContributionPlanEmployerDiscretionaryContributionAmount	1300000
	us-gaap	Defined Contribution Plan Employer Discretionary Contribution Amount DefinedContributionPlanEmployerDiscretionaryContributionAmount	934000
CY2024Q2	us-gaap	Employee Stock Ownership Plan Esop Number Of Committed To Be Released Shares EmployeeStockOwnershipPlanESOPNumberOfCommittedToBeReleasedShares	84709
CY2024Q2	us-gaap	Employee Stock Ownership Plan Esop Number Of Suspense Shares EmployeeStockOwnershipPlanESOPNumberOfSuspenseShares	3331749
CY2023Q4	us-gaap	Employee Stock Ownership Plan Esop Number Of Suspense Shares EmployeeStockOwnershipPlanESOPNumberOfSuspenseShares	1000000
CY2024Q2	us-gaap	Employee Stock Ownership Plan Esop Shares In Esop EmployeeStockOwnershipPlanESOPSharesInESOP	3416458
CY2023Q4	us-gaap	Employee Stock Ownership Plan Esop Shares In Esop EmployeeStockOwnershipPlanESOPSharesInESOP	1000000
CY2024Q2	us-gaap	Employee Stock Ownership Plan Esop Deferred Shares Fair Value EmployeeStockOwnershipPlanESOPDeferredSharesFairValue	50243000
CY2023Q4	us-gaap	Employee Stock Ownership Plan Esop Deferred Shares Fair Value EmployeeStockOwnershipPlanESOPDeferredSharesFairValue	13400000
CY2023Q2	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Purchases FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases	0
CY2024Q2	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Purchases FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases	0
CY2024Q2	us-gaap	Fair Value Disclosure Offbalance Sheet Risks Amount Liability FairValueDisclosureOffbalanceSheetRisksAmountLiability	947077000
CY2023Q4	us-gaap	Fair Value Disclosure Offbalance Sheet Risks Amount Liability FairValueDisclosureOffbalanceSheetRisksAmountLiability	1120402000
CY2024Q2	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	-762000
CY2023Q2	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	86000
	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	-223000
	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	86000
CY2024Q2	nbbk	Number Of Last Of Layer Hedges Previously Entered NumberOfLastOfLayerHedgesPreviouslyEntered	2
CY2021Q3	nbbk	Payments For Termination Of Hedge PaymentsForTerminationOfHedge	2200000
CY2024Q2	nbbk	Unamortized Amount Of Cost Basis Adjustment For Termination Of Layer Hedges UnamortizedAmountOfCostBasisAdjustmentForTerminationOfLayerHedges	982000
CY2023Q4	nbbk	Unamortized Amount Of Cost Basis Adjustment For Termination Of Layer Hedges UnamortizedAmountOfCostBasisAdjustmentForTerminationOfLayerHedges	1000000.0
CY2024Q2	us-gaap	Derivative Cost Of Hedge DerivativeCostOfHedge	26000
CY2023Q2	us-gaap	Derivative Cost Of Hedge DerivativeCostOfHedge	41000
	us-gaap	Derivative Cost Of Hedge DerivativeCostOfHedge	51000
	us-gaap	Derivative Cost Of Hedge DerivativeCostOfHedge	71000
CY2024Q2	nbbk	Number Of Agreements Held NumberOfAgreementsHeld	1
CY2024Q2	nbbk	Swap Contract Fees Net Of Brokerage Costs SwapContractFeesNetOfBrokerageCosts	265000
CY2023Q2	nbbk	Swap Contract Fees Net Of Brokerage Costs SwapContractFeesNetOfBrokerageCosts	1.0
	nbbk	Swap Contract Fees Net Of Brokerage Costs SwapContractFeesNetOfBrokerageCosts	752000
	nbbk	Swap Contract Fees Net Of Brokerage Costs SwapContractFeesNetOfBrokerageCosts	1100000
CY2024Q2	nbbk	Collateral Deposit Accounts Require To Maintain To Mitigate Counterparty Default Risk CollateralDepositAccountsRequireToMaintainToMitigateCounterpartyDefaultRisk	9100000
CY2023Q4	nbbk	Collateral Deposit Accounts Require To Maintain To Mitigate Counterparty Default Risk CollateralDepositAccountsRequireToMaintainToMitigateCounterpartyDefaultRisk	9100000
CY2024Q2	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Reclassification Adjustments And Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsAndTax	741000
CY2024Q2	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Before Reclassification Adjustments Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesBeforeReclassificationAdjustmentsTax	191000
CY2024Q2	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Reclassification Adjustments Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsNetOfTax	550000
CY2023Q2	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Reclassification Adjustments And Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsAndTax	-1363000
CY2023Q2	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Before Reclassification Adjustments Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesBeforeReclassificationAdjustmentsTax	-360000
CY2023Q2	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Reclassification Adjustments Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsNetOfTax	-1003000
CY2024Q2	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	741000
CY2024Q2	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesTax	191000
CY2024Q2	us-gaap	Other Comprehensive Income Availableforsale Securities Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent	550000
CY2023Q2	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	-1363000
CY2023Q2	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesTax	-360000
CY2023Q2	us-gaap	Other Comprehensive Income Availableforsale Securities Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent	-1003000
CY2023Q2	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	-50000
CY2023Q2	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationTax	-14000
CY2023Q2	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	-36000
CY2023Q2	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTaxParent	-50000
CY2023Q2	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax	14000
CY2023Q2	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent	-36000
CY2024Q2	us-gaap	Other Comprehensive Income Loss Before Tax OtherComprehensiveIncomeLossBeforeTax	741000
CY2024Q2	us-gaap	Other Comprehensive Income Loss Tax OtherComprehensiveIncomeLossTax	191000
CY2024Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	550000
CY2023Q2	us-gaap	Other Comprehensive Income Loss Before Tax OtherComprehensiveIncomeLossBeforeTax	-1413000
CY2023Q2	us-gaap	Other Comprehensive Income Loss Tax OtherComprehensiveIncomeLossTax	-374000
CY2023Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-1039000
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Reclassification Adjustments And Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsAndTax	1036000
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Before Reclassification Adjustments Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesBeforeReclassificationAdjustmentsTax	274000
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Reclassification Adjustments Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsNetOfTax	762000
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Reclassification Adjustments And Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsAndTax	350000
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Before Reclassification Adjustments Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesBeforeReclassificationAdjustmentsTax	70000
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Reclassification Adjustments Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsNetOfTax	280000
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	1036000
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesTax	274000
	us-gaap	Other Comprehensive Income Availableforsale Securities Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent	762000
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Before Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax	350000
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesTax	70000
	us-gaap	Other Comprehensive Income Availableforsale Securities Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent	280000
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	-321000
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationTax	-90000
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	-231000
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Before Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationBeforeTaxParent	-321000
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax	90000
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent	-231000
	us-gaap	Other Comprehensive Income Loss Before Tax OtherComprehensiveIncomeLossBeforeTax	1036000
	us-gaap	Other Comprehensive Income Loss Tax OtherComprehensiveIncomeLossTax	274000
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	762000
	us-gaap	Other Comprehensive Income Loss Before Tax OtherComprehensiveIncomeLossBeforeTax	29000
	us-gaap	Other Comprehensive Income Loss Tax OtherComprehensiveIncomeLossTax	-20000
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	49000
CY2024Q2	us-gaap	Accumulated Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-10166000
CY2023Q4	us-gaap	Accumulated Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-10928000
CY2024Q2	us-gaap	Accumulated Other Comprehensive Income Loss Defined Benefit Pension And Other Postretirement Plans Net Of Tax AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax	969000
CY2023Q4	us-gaap	Accumulated Other Comprehensive Income Loss Defined Benefit Pension And Other Postretirement Plans Net Of Tax AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax	969000
CY2024Q2	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-11135000
CY2023Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-11897000
CY2023Q4	us-gaap	Tier One Leverage Capital To Average Assets TierOneLeverageCapitalToAverageAssets	0.136
CY2024Q2	us-gaap	Capital Capital	646826000
CY2024Q2	us-gaap	Capital To Risk Weighted Assets CapitalToRiskWeightedAssets	0.146
CY2024Q2	us-gaap	Capital Required For Capital Adequacy CapitalRequiredForCapitalAdequacy	353544000
CY2024Q2	us-gaap	Capital Required For Capital Adequacy To Risk Weighted Assets CapitalRequiredForCapitalAdequacyToRiskWeightedAssets	0.080
CY2024Q2	us-gaap	Capital Required To Be Well Capitalized CapitalRequiredToBeWellCapitalized	441930000
CY2024Q2	us-gaap	Capital Required To Be Well Capitalized To Risk Weighted Assets CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets	0.100
CY2024Q2	us-gaap	Tier One Risk Based Capital TierOneRiskBasedCapital	603178000
CY2024Q2	us-gaap	Tier One Risk Based Capital To Risk Weighted Assets TierOneRiskBasedCapitalToRiskWeightedAssets	0.136
CY2024Q2	us-gaap	Tier One Risk Based Capital Required For Capital Adequacy TierOneRiskBasedCapitalRequiredForCapitalAdequacy	265158000
CY2024Q2	us-gaap	Tier One Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets	0.060
CY2024Q2	us-gaap	Tier One Risk Based Capital Required To Be Well Capitalized TierOneRiskBasedCapitalRequiredToBeWellCapitalized	353544000
CY2024Q2	us-gaap	Tier One Risk Based Capital Required To Be Well Capitalized To Risk Weighted Assets TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets	0.080
CY2024Q2	us-gaap	Common Equity Tier One Capital CommonEquityTierOneCapital	603178000
CY2024Q2	us-gaap	Common Equity Tier One Capital Ratio CommonEquityTierOneCapitalRatio	0.136
CY2024Q2	us-gaap	Common Equity Tier One Capital Required For Capital Adequacy CommonEquityTierOneCapitalRequiredForCapitalAdequacy	198869000
CY2024Q2	us-gaap	Banking Regulation Common Equity Tier One Risk Based Capital Ratio Capital Adequacy Minimum BankingRegulationCommonEquityTierOneRiskBasedCapitalRatioCapitalAdequacyMinimum	0.045
CY2024Q2	us-gaap	Common Equity Tier One Capital Required To Be Well Capitalized CommonEquityTierOneCapitalRequiredToBeWellCapitalized	287255000
CY2024Q2	us-gaap	Banking Regulation Common Equity Tier One Risk Based Capital Ratio Well Capitalized Minimum BankingRegulationCommonEquityTierOneRiskBasedCapitalRatioWellCapitalizedMinimum	0.065
CY2024Q2	us-gaap	Tier One Leverage Capital TierOneLeverageCapital	603178000
CY2024Q2	us-gaap	Tier One Leverage Capital To Average Assets TierOneLeverageCapitalToAverageAssets	0.132
CY2024Q2	us-gaap	Tier One Leverage Capital Required For Capital Adequacy TierOneLeverageCapitalRequiredForCapitalAdequacy	182896000
CY2024Q2	us-gaap	Tier One Leverage Capital Required For Capital Adequacy To Average Assets TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets	0.040
CY2024Q2	us-gaap	Tier One Leverage Capital Required To Be Well Capitalized TierOneLeverageCapitalRequiredToBeWellCapitalized	228620000
CY2024Q2	us-gaap	Tier One Leverage Capital Required To Be Well Capitalized To Average Assets TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets	0.050
	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	0
CY2023Q2	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	0
	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	0
CY2024Q2	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	0
CY2024Q2	us-gaap	Net Income Loss NetIncomeLoss	9453000
	us-gaap	Net Income Loss NetIncomeLoss	18154000
CY2024Q2	us-gaap	Weighted Average Number Of Shares Issued Basic WeightedAverageNumberOfSharesIssuedBasic	42705729
	us-gaap	Weighted Average Number Of Shares Issued Basic WeightedAverageNumberOfSharesIssuedBasic	42705729
CY2024Q2	us-gaap	Weighted Average Number Of Shares Employee Stock Ownership Plan Shares Not Committed To Be Released WeightedAverageNumberOfSharesEmployeeStockOwnershipPlanSharesNotCommittedToBeReleased	3416458
	us-gaap	Weighted Average Number Of Shares Employee Stock Ownership Plan Shares Not Committed To Be Released WeightedAverageNumberOfSharesEmployeeStockOwnershipPlanSharesNotCommittedToBeReleased	3215177
CY2024Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	39289271
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	39490552
CY2024Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	39289271
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	39490552
CY2024Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.24
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.46
	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	0
CY2023Q2	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	0
	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	0
CY2024Q2	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	0
CY2024Q2	ecd	Rule10b51 Arr Adopted Flag Rule10b51ArrAdoptedFlag	false
CY2024Q2	ecd	Non Rule10b51 Arr Adopted Flag NonRule10b51ArrAdoptedFlag	false
CY2024Q2	ecd	Rule10b51 Arr Trmntd Flag Rule10b51ArrTrmntdFlag	false
CY2024Q2	ecd	Non Rule10b51 Arr Trmntd Flag NonRule10b51ArrTrmntdFlag	false

Files In Submission

Name	View Source	Status
0001558370-24-011709-index-headers.html	Edgar Link	pending
0001558370-24-011709-index.html	Edgar Link	pending
0001558370-24-011709.txt	Edgar Link	pending
0001558370-24-011709-xbrl.zip	Edgar Link	pending
Financial_Report.xlsx	Edgar Link	pending
MetaLinks.json	Edgar Link	pending
nbbk-20240630.xsd	Edgar Link	pending
nbbk-20240630x10q.htm	Edgar Link	pending
nbbk-20240630xex31d1.htm	Edgar Link	pending
nbbk-20240630xex31d2.htm	Edgar Link	pending
nbbk-20240630xex32.htm	Edgar Link	pending
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R39.htm	Edgar Link	pending
R4.htm	Edgar Link	pending
nbbk-20240630_cal.xml	Edgar Link	unprocessable
nbbk-20240630_def.xml	Edgar Link	unprocessable
nbbk-20240630_pre.xml	Edgar Link	unprocessable
nbbk-20240630x10q_htm.xml	Edgar Link	completed
R40.htm	Edgar Link	pending
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R9.htm	Edgar Link	pending
report.css	Edgar Link	pending
Show.js	Edgar Link	pending
FilingSummary.xml	Edgar Link	unprocessable
nbbk-20240630_lab.xml	Edgar Link	unprocessable

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2024 Q3 Form 10-Q Financial Statement

#000155837024011709 Filed on August 09, 2024

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$NBBK NB Bancorp, Inc. Stock $nbbk

2024 Q3 Form 10-Q Financial Statement

#000155837024011709 Filed on August 09, 2024

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$NBBK
NB Bancorp, Inc. Stock $nbbk