$NBTB
NBT BANCORP INC Stock $nbtb

$nbtb Overview Financials Valuation SEC Filings Company Website

2019 Q4 Form 10-K Financial Statement

#000114036121006657 Filed on March 01, 2021

Income Statement

Concept	2019 Q4	2018 Q4	2018
Revenue			$344.3M
YoY Change			11.26%
Cost Of Revenue
YoY Change
Gross Profit
YoY Change
Gross Profit Margin
Selling, General & Admin
YoY Change
% of Gross Profit
Research & Development			$17.65M
YoY Change			3.42%
% of Gross Profit
Depreciation & Amortization	$3.300M	$3.200M	$13.30M
YoY Change	3.13%	-3.03%	1.53%
% of Gross Profit
Operating Expenses			$17.65M
YoY Change			3.42%
Operating Profit
YoY Change
Interest Expense			$38.63M
YoY Change			49.05%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	$37.10M	$29.40M	$137.0M
YoY Change	26.19%	-11.71%	6.9%
Income Tax	$8.200M	$6.100M	$24.44M
% Of Pretax Income	22.1%	20.75%	17.84%
Net Earnings	$29.00M	$28.70M	$112.6M
YoY Change	1.05%	63.07%	37.02%
Net Earnings / Revenue			32.7%
Basic Earnings Per Share			$2.58
Diluted Earnings Per Share	$656.1K	$650.8K	$2.56
COMMON SHARES
Basic Shares Outstanding	43.79M		43.70M
Diluted Shares Outstanding			44.02M

Balance Sheet

Concept	2019 Q4	2018 Q4	2018
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$216.8M	$181.0M
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	$75.63M	$78.97M	$79.00M
YoY Change	-4.23%	-2.51%	-2.47%
Goodwill	$274.8M	$274.8M
YoY Change	0.0%	2.51%
Intangibles	$12.02M	$15.60M
YoY Change	-22.94%
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	$9.716B	$9.556B	$9.556B
YoY Change	1.67%	4.59%	4.59%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable
YoY Change
Accrued Expenses	$37.00M
YoY Change
Deferred Revenue
YoY Change
Short-Term Debt	$655.3M	$871.7M	$872.0M
YoY Change	-24.83%	21.24%	21.28%
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$37.00M	$872.0M	$872.0M
YoY Change	-95.76%	21.28%	21.28%
LONG-TERM LIABILITIES
Long-Term Debt	$165.0M	$175.0M	$175.0M
YoY Change	-5.71%	-7.89%	-7.89%
Other Long-Term Liabilities	$150.0M	$124.0M	$124.0M
YoY Change	20.97%	25.25%	25.25%
Total Long-Term Liabilities	$315.0M	$299.0M	$299.0M
YoY Change	5.35%	3.46%	3.46%
TOTAL LIABILITIES
Total Short-Term Liabilities	$37.00M	$872.0M	$872.0M
Total Long-Term Liabilities	$315.0M	$299.0M	$299.0M
Total Liabilities	$8.596B	$8.538B	$8.538B
YoY Change	0.67%	4.39%	4.39%
SHAREHOLDERS EQUITY
Retained Earnings	$696.2M	$621.2M
YoY Change	12.08%
Common Stock	$497.0K	$497.0K
YoY Change	0.0%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$134.0M	$136.1M
YoY Change	-1.53%
Treasury Stock Shares	$5.855M	$5.979M
Shareholders Equity	$1.120B	$1.018B	$1.018B
YoY Change
Total Liabilities & Shareholders Equity	$9.716B	$9.556B	$9.556B
YoY Change	1.67%	4.59%	4.59%

Cashflow Statement

Concept	2019 Q4	2018 Q4	2018
OPERATING ACTIVITIES
Net Income	$29.00M	$28.70M	$112.6M
YoY Change	1.05%	63.07%	37.02%
Depreciation, Depletion And Amortization	$3.300M	$3.200M	$13.30M
YoY Change	3.13%	-3.03%	1.53%
Cash From Operating Activities	$49.50M	$48.00M	$147.8M
YoY Change	3.12%	19.11%	7.94%
INVESTING ACTIVITIES
Capital Expenditures	-$2.600M	-$3.100M	-$7.400M
YoY Change	-16.13%	24.0%	10.45%
Acquisitions			$7.884M
YoY Change			97.1%
Other Investing Activities	-$129.1M	-$14.10M	-$410.2M
YoY Change	815.6%	-47.39%	37.42%
Cash From Investing Activities	-$131.7M	-$17.20M	-$417.6M
YoY Change	665.7%	-41.3%	36.84%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net			$0.00
YoY Change
Debt Paid & Issued, Net			$40.15M
YoY Change			-0.18%
Cash From Financing Activities	25.00M	-24.50M	291.1M
YoY Change	-202.04%	-26.2%	62.85%
NET CHANGE
Cash From Operating Activities	49.50M	48.00M	147.8M
Cash From Investing Activities	-131.7M	-17.20M	-417.6M
Cash From Financing Activities	25.00M	-24.50M	291.1M
Net Change In Cash	-57.20M	6.300M	21.29M
YoY Change	-1007.94%	-128.38%	103.1%
FREE CASH FLOW
Cash From Operating Activities	$49.50M	$48.00M	$147.8M
Capital Expenditures	-$2.600M	-$3.100M	-$7.400M
Free Cash Flow	$52.10M	$51.10M	$155.2M
YoY Change	1.96%	19.39%	8.06%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value
CY2020	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2020	dei	Amendment Flag AmendmentFlag	false
CY2020	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2020
CY2020	dei	Entity Central Index Key EntityCentralIndexKey	0000790359
CY2020	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2020	dei	Entity Address State Or Province EntityAddressStateOrProvince	NY
CY2019Q4	us-gaap	Operating Lease Right Of Use Asset Statement Of Financial Position Extensible List OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList	us-gaap:OtherAssets
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset Statement Of Financial Position Extensible List OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList	us-gaap:OtherAssets
CY2020Q4	us-gaap	Operating Lease Liability Statement Of Financial Position Extensible List OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList	us-gaap:OtherLiabilities
CY2019Q4	us-gaap	Operating Lease Liability Statement Of Financial Position Extensible List OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList	us-gaap:OtherLiabilities
CY2020	dei	Document Type DocumentType	10-K
CY2020	dei	Document Annual Report DocumentAnnualReport	true
CY2020	dei	Document Period End Date DocumentPeriodEndDate	2020-12-31
CY2020	dei	Entity File Number EntityFileNumber	0-14703
CY2020	dei	Entity Registrant Name EntityRegistrantName	NBT BANCORP INC
CY2020	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	DE
CY2020	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	16-1268674
CY2020	dei	Entity Address Address Line1 EntityAddressAddressLine1	52 SOUTH BROAD STREET
CY2020	dei	Entity Address City Or Town EntityAddressCityOrTown	NORWICH
CY2020	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	13815
CY2020	dei	City Area Code CityAreaCode	607
CY2020	dei	Local Phone Number LocalPhoneNumber	337-2265
CY2020	dei	Security12b Title Security12bTitle	Common Stock, par value $0.01 per share
CY2020	dei	Trading Symbol TradingSymbol	NBTB
CY2020	dei	Security Exchange Name SecurityExchangeName	NASDAQ
CY2020	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	Yes
CY2020	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2020	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2020	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
CY2020	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
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CY2020	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
CY2020	dei	Document Transition Report DocumentTransitionReport	false
CY2020	dei	Entity Shell Company EntityShellCompany	false
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CY2018	us-gaap	Supplies And Postage Expense SuppliesAndPostageExpense	6204000
CY2020	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	2688000
CY2019	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	1946000
CY2018	us-gaap	Federal Deposit Insurance Corporation Premium Expense FederalDepositInsuranceCorporationPremiumExpense	4651000
CY2020	us-gaap	Advertising Expense AdvertisingExpense	2288000
CY2019	us-gaap	Advertising Expense AdvertisingExpense	2773000
CY2018	us-gaap	Advertising Expense AdvertisingExpense	2782000
CY2020	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	3395000
CY2019	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	3579000
CY2018	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	4042000
CY2020	nbtb	Loan Collection And Other Real Estate Owned LoanCollectionAndOtherRealEstateOwned	3295000
CY2019	nbtb	Loan Collection And Other Real Estate Owned LoanCollectionAndOtherRealEstateOwned	4158000
CY2018	nbtb	Loan Collection And Other Real Estate Owned LoanCollectionAndOtherRealEstateOwned	4217000
CY2020	us-gaap	Other Noninterest Expense OtherNoninterestExpense	24863000
CY2019	us-gaap	Other Noninterest Expense OtherNoninterestExpense	24440000
CY2018	us-gaap	Other Noninterest Expense OtherNoninterestExpense	19597000
CY2020	us-gaap	Noninterest Expense NoninterestExpense	277733000
CY2019	us-gaap	Noninterest Expense NoninterestExpense	274734000
CY2018	us-gaap	Noninterest Expense NoninterestExpense	264561000
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	133087000
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	155432000
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	137002000
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	28699000
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	34411000
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	24436000
CY2020	us-gaap	Net Income Loss NetIncomeLoss	104388000
CY2019	us-gaap	Net Income Loss NetIncomeLoss	121021000
CY2018	us-gaap	Net Income Loss NetIncomeLoss	112566000
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.39
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.76
CY2018	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.58
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.37
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.74
CY2018	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.56
CY2020	us-gaap	Net Income Loss NetIncomeLoss	104388000
CY2019	us-gaap	Net Income Loss NetIncomeLoss	121021000
CY2018	us-gaap	Net Income Loss NetIncomeLoss	112566000
CY2020	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	23204000
CY2018	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	-811000
CY2020	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansBeforeTax	1627000
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansBeforeTax	2686000
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansBeforeTax	1145000
CY2019	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	25836000
CY2018	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-11985000
CY2020	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	5800000
CY2019	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	6459000
CY2018	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-2996000
CY2020	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	17404000
CY2019	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	19377000
CY2018	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-8989000
CY2020	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	3000
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	-79000
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	-6622000
CY2020	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	1000
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	-20000
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	-1655000
CY2020	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	2000
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	-59000
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	-4967000
CY2020	nbtb	Other Comprehensive Income Loss Transfers From Available For Sale To Held To Maturity Securities Before Tax OtherComprehensiveIncomeLossTransfersFromAvailableForSaleToHeldToMaturitySecuritiesBeforeTax	644000
CY2019	nbtb	Other Comprehensive Income Loss Transfers From Available For Sale To Held To Maturity Securities Before Tax OtherComprehensiveIncomeLossTransfersFromAvailableForSaleToHeldToMaturitySecuritiesBeforeTax	737000
CY2018	nbtb	Other Comprehensive Income Loss Transfers From Available For Sale To Held To Maturity Securities Before Tax OtherComprehensiveIncomeLossTransfersFromAvailableForSaleToHeldToMaturitySecuritiesBeforeTax	688000
CY2020	nbtb	Other Comprehensive Income Loss Transfers From Available For Sale To Held To Maturity Securities Tax OtherComprehensiveIncomeLossTransfersFromAvailableForSaleToHeldToMaturitySecuritiesTax	161000
CY2019	nbtb	Other Comprehensive Income Loss Transfers From Available For Sale To Held To Maturity Securities Tax OtherComprehensiveIncomeLossTransfersFromAvailableForSaleToHeldToMaturitySecuritiesTax	184000
CY2018	nbtb	Other Comprehensive Income Loss Transfers From Available For Sale To Held To Maturity Securities Tax OtherComprehensiveIncomeLossTransfersFromAvailableForSaleToHeldToMaturitySecuritiesTax	172000
CY2020	nbtb	Other Comprehensive Income Loss Transfers From Available For Sale To Held To Maturity Securities Net Of Tax OtherComprehensiveIncomeLossTransfersFromAvailableForSaleToHeldToMaturitySecuritiesNetOfTax	483000
CY2019	nbtb	Other Comprehensive Income Loss Transfers From Available For Sale To Held To Maturity Securities Net Of Tax OtherComprehensiveIncomeLossTransfersFromAvailableForSaleToHeldToMaturitySecuritiesNetOfTax	553000
CY2018	nbtb	Other Comprehensive Income Loss Transfers From Available For Sale To Held To Maturity Securities Net Of Tax OtherComprehensiveIncomeLossTransfersFromAvailableForSaleToHeldToMaturitySecuritiesNetOfTax	516000
CY2020	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	17885000
CY2019	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	19989000
CY2018	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-3506000
CY2020	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax	-275000
CY2019	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax	-459000
CY2018	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax	1218000
CY2020	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax	-69000
CY2019	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax	-115000
CY2018	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax	304000
CY2020	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	-206000
CY2019	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	-344000
CY2018	us-gaap	Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax	914000
CY2020	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesBeforeTax	-296000
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesBeforeTax	2012000
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesBeforeTax	2300000
CY2020	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesTax	-74000
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesTax	503000
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesTax	575000
CY2020	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesNetOfTax	-222000
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesNetOfTax	1509000
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci On Derivatives Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesNetOfTax	1725000
CY2020	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	16000
CY2019	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	-1853000
CY2018	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	8560000
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	19443000
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	24148000
CY2018	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-12877000
CY2018	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	3936000
CY2018	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-12877000
CY2018Q4	us-gaap	Stockholders Equity StockholdersEquity	1017909000
CY2019	us-gaap	Net Income Loss NetIncomeLoss	121021000
CY2019	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.05
CY2019	us-gaap	Dividends Cash DividendsCash	46010000
CY2020	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansTax	407000
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansTax	672000
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansTax	286000
CY2020	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansNetOfTax	1220000
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansNetOfTax	2014000
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansNetOfTax	859000
CY2020	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	429000
CY2019	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	5331000
CY2018	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	-12457000
CY2020	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax	107000
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax	1333000
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax	-3038000
CY2020	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax	322000
CY2019	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax	3998000
CY2018	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax	-9419000
CY2020	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-1542000
CY2019	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-6012000
CY2020	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	123831000
CY2019	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	145169000
CY2018	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	99689000
CY2017Q4	us-gaap	Stockholders Equity StockholdersEquity	958177000
CY2018	us-gaap	Net Income Loss NetIncomeLoss	112566000
CY2018	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.99
CY2018	us-gaap	Dividends Cash DividendsCash	43269000
CY2018	nbtb	Stock Issued During Period Shares Employee Benefit Plans And Other Stock Plans StockIssuedDuringPeriodSharesEmployeeBenefitPlansAndOtherStockPlans	130157
CY2018	nbtb	Stock Issued During Period Value Employee Benefit Plans And Other Stock Plans StockIssuedDuringPeriodValueEmployeeBenefitPlansAndOtherStockPlans	-597000
CY2019	nbtb	Stock Issued During Period Shares Employee Benefit Plans And Other Stock Plans StockIssuedDuringPeriodSharesEmployeeBenefitPlansAndOtherStockPlans	123645
CY2019	nbtb	Stock Issued During Period Value Employee Benefit Plans And Other Stock Plans StockIssuedDuringPeriodValueEmployeeBenefitPlansAndOtherStockPlans	-881000
CY2019	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	4210000
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	24148000
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	1120397000
CY2020	us-gaap	Net Income Loss NetIncomeLoss	104388000
CY2020	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.08
CY2020	us-gaap	Dividends Cash DividendsCash	47207000
CY2020	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	263507
CY2020	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	7980000
CY2020	nbtb	Stock Issued During Period Shares Employee Benefit Plans And Other Stock Plans StockIssuedDuringPeriodSharesEmployeeBenefitPlansAndOtherStockPlans	95990
CY2020	nbtb	Stock Issued During Period Value Employee Benefit Plans And Other Stock Plans StockIssuedDuringPeriodValueEmployeeBenefitPlansAndOtherStockPlans	-1665000
CY2020	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	4581000
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	19443000
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	1187618000
CY2020	us-gaap	Gain Loss On Termination Of Lease GainLossOnTerminationOfLease	-4284000
CY2020	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	51134000
CY2019	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	25412000
CY2018	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	28828000
CY2020	us-gaap	Amortization Of Financing Costs AmortizationOfFinancingCosts	230000
CY2019	us-gaap	Amortization Of Financing Costs AmortizationOfFinancingCosts	0
CY2018	us-gaap	Amortization Of Financing Costs AmortizationOfFinancingCosts	0
CY2019	us-gaap	Gain Loss On Termination Of Lease GainLossOnTerminationOfLease	-1872000
CY2018	us-gaap	Gain Loss On Termination Of Lease GainLossOnTerminationOfLease	0
CY2020	nbtb	Proceeds From Calls Of Equity Securities ProceedsFromCallsOfEquitySecurities	2000000
CY2019	nbtb	Proceeds From Calls Of Equity Securities ProceedsFromCallsOfEquitySecurities	0
CY2018	nbtb	Proceeds From Calls Of Equity Securities ProceedsFromCallsOfEquitySecurities	0
CY2020	us-gaap	Proceeds From Issuance Of Subordinated Long Term Debt ProceedsFromIssuanceOfSubordinatedLongTermDebt	100000000
CY2019	us-gaap	Proceeds From Issuance Of Subordinated Long Term Debt ProceedsFromIssuanceOfSubordinatedLongTermDebt	0
CY2018	us-gaap	Proceeds From Issuance Of Subordinated Long Term Debt ProceedsFromIssuanceOfSubordinatedLongTermDebt	0
CY2020	us-gaap	Payments Of Debt Issuance Costs PaymentsOfDebtIssuanceCosts	2178000
CY2019	us-gaap	Payments Of Debt Issuance Costs PaymentsOfDebtIssuanceCosts	0
CY2018	us-gaap	Payments Of Debt Issuance Costs PaymentsOfDebtIssuanceCosts	0
CY2020	us-gaap	Proceeds From Issuance Of Other Long Term Debt ProceedsFromIssuanceOfOtherLongTermDebt	0
CY2019	us-gaap	Proceeds From Issuance Of Other Long Term Debt ProceedsFromIssuanceOfOtherLongTermDebt	10598000
CY2018	us-gaap	Proceeds From Issuance Of Other Long Term Debt ProceedsFromIssuanceOfOtherLongTermDebt	25000000
CY2020	us-gaap	Repayments Of Other Long Term Debt RepaymentsOfOtherLongTermDebt	25114000
CY2019	us-gaap	Repayments Of Other Long Term Debt RepaymentsOfOtherLongTermDebt	20111000
CY2018	us-gaap	Repayments Of Other Long Term Debt RepaymentsOfOtherLongTermDebt	40145000
CY2020	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	7980000
CY2019	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	0
CY2018	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	0
CY2020	us-gaap	Use Of Estimates UseOfEstimates	<div style="text-align: justify; font-family: 'Times New Roman'; font-size: 10pt;">Estimates associated with the allowance for credit losses, provision for income taxes, pension accounting, fair values of financial instruments and status of contingencies are particularly susceptible to material change in the near term.</div>
CY2020	nbtb	Threshold Period Past Due For Loans To Be Considered Nonperforming ThresholdPeriodPastDueForLoansToBeConsideredNonperforming	P90D
CY2020	nbtb	Period Of Sustained Repayment Performance For Nonperforming Tdrs To Be Returned To Performing Status PeriodOfSustainedRepaymentPerformanceForNonperformingTdrsToBeReturnedToPerformingStatus	P6M
CY2020	nbtb	Standby Letters Of Credit Expiration Period StandbyLettersOfCreditExpirationPeriod	P1Y
CY2020	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	140921000
CY2019	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	134455000
CY2018	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	126012000
CY2020	nbtb	Non Interest Income1 NonInterestIncome1	5355000
CY2019	nbtb	Non Interest Income1 NonInterestIncome1	9568000
CY2018	nbtb	Non Interest Income1 NonInterestIncome1	-1250000
CY2020	us-gaap	Noninterest Income NoninterestIncome	146276000
CY2019	us-gaap	Noninterest Income NoninterestIncome	144023000
CY2018	us-gaap	Noninterest Income NoninterestIncome	124762000
CY2020Q4	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss DebtSecuritiesAvailableForSaleAllowanceForCreditLoss	0
CY2020Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	1318711000
CY2020Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	32166000
CY2020Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	2179000
CY2020Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	1348698000
CY2019Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	968554000
CY2019Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	8319000
CY2019Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	1533000
CY2019Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	975340000
CY2020	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	3000
CY2019	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	73000
CY2018	us-gaap	Debt Securities Available For Sale Realized Gain DebtSecuritiesAvailableForSaleRealizedGain	0
CY2020	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	0
CY2019	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	152000
CY2018	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	6622000
CY2020	us-gaap	Debt Securities Available For Sale Realized Gain Loss DebtSecuritiesAvailableForSaleRealizedGainLoss	3000
CY2019	us-gaap	Debt Securities Available For Sale Realized Gain Loss DebtSecuritiesAvailableForSaleRealizedGainLoss	-79000
CY2018	us-gaap	Debt Securities Available For Sale Realized Gain Loss DebtSecuritiesAvailableForSaleRealizedGainLoss	-6622000
CY2020	nbtb	Gains From Calls On Securities Available For Sale GainsFromCallsOnSecuritiesAvailableForSale	3000
CY2019	nbtb	Gains From Calls On Securities Available For Sale GainsFromCallsOnSecuritiesAvailableForSale	25000
CY2018	nbtb	Gains From Calls On Securities Available For Sale GainsFromCallsOnSecuritiesAvailableForSale	0
CY2020Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	616560000
CY2020Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	21942000
CY2020Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	1675000
CY2020Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	636827000
CY2019Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	630074000
CY2019Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	11817000
CY2019Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	629000
CY2019Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	641262000
CY2020Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	0
CY2020	nbtb	Gains From Calls On Securities Held To Maturity GainsFromCallsOnSecuritiesHeldToMaturity	24000
CY2019	nbtb	Gains From Calls On Securities Held To Maturity GainsFromCallsOnSecuritiesHeldToMaturity	12000
CY2018	nbtb	Gains From Calls On Securities Held To Maturity GainsFromCallsOnSecuritiesHeldToMaturity	0
CY2020	us-gaap	Debt Securities Held To Maturity Sold Amount DebtSecuritiesHeldToMaturitySoldAmount	1000000.0
CY2020	nbtb	Debt Securities Held To Maturity Sold Realized Loss DebtSecuritiesHeldToMaturitySoldRealizedLoss	1000
CY2018	us-gaap	Debt Securities Held To Maturity Sold Amount DebtSecuritiesHeldToMaturitySoldAmount	0
CY2019	us-gaap	Debt Securities Held To Maturity Sold Amount DebtSecuritiesHeldToMaturitySoldAmount	0
CY2020	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	-414000
CY2019	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	4280000
CY2020	us-gaap	Equity Securities Fv Ni Realized Gain Loss EquitySecuritiesFvNiRealizedGainLoss	0
CY2019	us-gaap	Equity Securities Fv Ni Realized Gain Loss EquitySecuritiesFvNiRealizedGainLoss	3966000
CY2020	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	-414000
CY2019	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	314000
CY2020Q4	us-gaap	Equity Securities Without Readily Determinable Fair Value Amount EquitySecuritiesWithoutReadilyDeterminableFairValueAmount	2000000.0
CY2019Q4	us-gaap	Equity Securities Without Readily Determinable Fair Value Amount EquitySecuritiesWithoutReadilyDeterminableFairValueAmount	4000000.0
CY2020	us-gaap	Equity Securities Without Readily Determinable Fair Value Impairment Loss Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossAnnualAmount	0
CY2019	us-gaap	Equity Securities Without Readily Determinable Fair Value Upward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentAnnualAmount	0
CY2019	us-gaap	Equity Securities Without Readily Determinable Fair Value Downward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentAnnualAmount	0
CY2020	us-gaap	Equity Securities Without Readily Determinable Fair Value Upward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentAnnualAmount	0
CY2020	us-gaap	Equity Securities Without Readily Determinable Fair Value Downward Price Adjustment Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentAnnualAmount	0
CY2019	us-gaap	Equity Securities Without Readily Determinable Fair Value Impairment Loss Annual Amount EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossAnnualAmount	0
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost	438000
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue	449000
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost	21476000
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	22324000
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost	545330000
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost	751467000
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue	774710000
CY2020Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	1318711000
CY2020Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	1348698000
CY2020Q4	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount	18088000
CY2020Q4	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Fair Value HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue	18104000
CY2020Q4	us-gaap	Held To Maturity Securities Debt Maturities After One Through Five Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsNetCarryingAmount	58963000
CY2020Q4	us-gaap	Held To Maturity Securities Debt Maturities After One Through Five Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	60483000
CY2020Q4	us-gaap	Held To Maturity Securities Debt Maturities After Five Through Ten Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsNetCarryingAmount	231927000
CY2020Q4	us-gaap	Held To Maturity Securities Debt Maturities After Five Through Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	237275000
CY2020Q4	us-gaap	Held To Maturity Securities Debt Maturities After Ten Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount	307582000
CY2020Q4	us-gaap	Held To Maturity Securities Debt Maturities After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue	320965000
CY2020Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	616560000
CY2020Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	636827000
CY2019Q4	nbtb	Number Of Issuers Whose Holdings Exceeded Ten Percent Of Consolidated Stockholders Equity Excluding Us Government Securities NumberOfIssuersWhoseHoldingsExceededTenPercentOfConsolidatedStockholdersEquityExcludingUSGovernmentSecurities	0
CY2020Q4	nbtb	Number Of Issuers Whose Holdings Exceeded Ten Percent Of Consolidated Stockholders Equity Excluding Us Government Securities NumberOfIssuersWhoseHoldingsExceededTenPercentOfConsolidatedStockholdersEquityExcludingUSGovernmentSecurities	0
CY2020Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	213643000
CY2020Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	2170000
CY2020Q4	us-gaap	Available For Sale Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions Less Than One Year AvailableForSaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositionsLessThanOneYear	19
CY2020Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	800000
CY2020Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	9000
CY2020Q4	us-gaap	Availableforsale Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions Greater Than Or Equal To One Year AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositionsGreaterThanOrEqualToOneYear	4
CY2020Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue	214443000
CY2020Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	2179000
CY2020Q4	us-gaap	Availableforsale Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions1 AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1	23
CY2020Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	103147000
CY2020Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	1675000
CY2020Q4	nbtb	Held To Maturity Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions Less Than One Year HeldToMaturitySecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositionsLessThanOneYear	9
CY2020Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	0
CY2020Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	0
CY2020Q4	nbtb	Held To Maturity Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions Greater Than Or Equal To One Year HeldToMaturitySecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositionsGreaterThanOrEqualToOneYear	0
CY2020Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue	103147000
CY2020Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	1675000
CY2020Q4	us-gaap	Held To Maturity Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions HeldToMaturitySecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions	9
CY2019Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	198501000
CY2019Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	718000
CY2019Q4	us-gaap	Available For Sale Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions Less Than One Year AvailableForSaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositionsLessThanOneYear	48
CY2019Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	97243000
CY2019Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	815000
CY2019Q4	us-gaap	Availableforsale Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions Greater Than Or Equal To One Year AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositionsGreaterThanOrEqualToOneYear	34
CY2019Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue	295744000
CY2019Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	1533000
CY2019Q4	us-gaap	Availableforsale Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions1 AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1	82
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	20297000
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	187000
CY2019	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	25400000
CY2019Q4	nbtb	Held To Maturity Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions Less Than One Year HeldToMaturitySecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositionsLessThanOneYear	7
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	47759000
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	442000
CY2019Q4	nbtb	Held To Maturity Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions Greater Than Or Equal To One Year HeldToMaturitySecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositionsGreaterThanOrEqualToOneYear	7
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue	68056000
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	629000
CY2019Q4	us-gaap	Held To Maturity Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions HeldToMaturitySecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions	14
CY2020Q4	us-gaap	Availableforsale Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions1 AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1	23
CY2020Q4	us-gaap	Debt Securities Available For Sale Accrued Interest After Allowance For Credit Loss DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLoss	3300000
CY2020Q4	us-gaap	Debt Securities Held To Maturity Past Due DebtSecuritiesHeldToMaturityPastDue	0
CY2020	nbtb	Debt Securities Held To Maturity Accrued Interest Receivables Reversed DebtSecuritiesHeldToMaturityAccruedInterestReceivablesReversed	0
CY2020Q4	nbtb	Debt Securities Held To Maturity Collateral Dependent DebtSecuritiesHeldToMaturityCollateralDependent	0
CY2020Q4	us-gaap	Debt Securities Held To Maturity Accrued Interest After Allowance For Credit Loss DebtSecuritiesHeldToMaturityAccruedInterestAfterAllowanceForCreditLoss	2700000
CY2020Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	7498885000
CY2019Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	7136098000
CY2020Q4	us-gaap	Unamortized Loan Commitment And Origination Fees And Unamortized Discounts Or Premiums UnamortizedLoanCommitmentAndOriginationFeesAndUnamortizedDiscountsOrPremiums	9400000
CY2019Q4	us-gaap	Unamortized Loan Commitment And Origination Fees And Unamortized Discounts Or Premiums UnamortizedLoanCommitmentAndOriginationFeesAndUnamortizedDiscountsOrPremiums	35300000
CY2020Q4	us-gaap	Loans Receivable Held For Sale Net Not Part Of Disposal Group LoansReceivableHeldForSaleNetNotPartOfDisposalGroup	1100000
CY2019Q4	us-gaap	Loans Receivable Held For Sale Net Not Part Of Disposal Group LoansReceivableHeldForSaleNetNotPartOfDisposalGroup	11500000
CY2020Q4	nbtb	Loans Serviced For Others LoansServicedForOthers	614500000
CY2019Q4	nbtb	Loans Serviced For Others LoansServicedForOthers	612300000
CY2020Q4	us-gaap	Servicing Asset At Amortized Value ServicingAssetAtAmortizedValue	1300000
CY2019Q4	us-gaap	Servicing Asset At Amortized Value ServicingAssetAtAmortizedValue	800000
CY2020Q4	us-gaap	Financing Receivable Originated Five Or More Years Before Latest Fiscal Year FinancingReceivableOriginatedFiveOrMoreYearsBeforeLatestFiscalYear	1262066000
CY2020Q4	us-gaap	Financing Receivable Revolving FinancingReceivableRevolving	749657000
CY2020Q4	us-gaap	Financing Receivable Revolving Converted To Term Loan FinancingReceivableRevolvingConvertedToTermLoan	30688000
CY2020Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	7498885000
CY2019Q4	nbtb	Financing Receivable Allowance For Credit Losses Percentage FinancingReceivableAllowanceForCreditLossesPercentage	0.0102
CY2020	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	51100000
CY2020Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	24273000
CY2019Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	31554000
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	10023000
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	36814000
CY2019Q4	us-gaap	Loans And Leases Receivable Related Parties LoansAndLeasesReceivableRelatedParties	2166000
CY2018Q4	us-gaap	Loans And Leases Receivable Related Parties LoansAndLeasesReceivableRelatedParties	1638000
CY2020	us-gaap	Loans And Leases Receivable Related Parties Additions LoansAndLeasesReceivableRelatedPartiesAdditions	1524000
CY2019	us-gaap	Loans And Leases Receivable Related Parties Additions LoansAndLeasesReceivableRelatedPartiesAdditions	587000
CY2020	nbtb	Loans And Leases Receivable Related Parties Composition Period Increase Decrease LoansAndLeasesReceivableRelatedPartiesCompositionPeriodIncreaseDecrease	2448000
CY2019	nbtb	Loans And Leases Receivable Related Parties Composition Period Increase Decrease LoansAndLeasesReceivableRelatedPartiesCompositionPeriodIncreaseDecrease	389000
CY2020	us-gaap	Loans And Leases Receivable Related Parties Proceeds LoansAndLeasesReceivableRelatedPartiesProceeds	202000
CY2019	us-gaap	Loans And Leases Receivable Related Parties Proceeds LoansAndLeasesReceivableRelatedPartiesProceeds	448000
CY2020Q4	us-gaap	Loans And Leases Receivable Related Parties LoansAndLeasesReceivableRelatedParties	5936000
CY2019Q4	us-gaap	Loans And Leases Receivable Related Parties LoansAndLeasesReceivableRelatedParties	2166000
CY2020	nbtb	Loans Purchased With Credit Deterioration LoansPurchasedWithCreditDeterioration	0
CY2019Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	73000000.0
CY2020Q4	nbtb	Financing Receivable Allowance For Credit Losses Percentage FinancingReceivableAllowanceForCreditLossesPercentage	0.0147
CY2020Q4	nbtb	Financing Receivable Individually Evaluated For Impairment Number Of Relationships FinancingReceivableIndividuallyEvaluatedForImpairmentNumberOfRelationships	5
CY2020Q4	nbtb	Loans And Leases Receivable Individually Evaluated For Impairment LoansAndLeasesReceivableIndividuallyEvaluatedForImpairment	15200000
CY2020Q4	nbtb	Loans And Leases Receivable Allowance For Credit Losses Individually Evaluated For Impairment LoansAndLeasesReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment	3200000
CY2019Q4	nbtb	Financing Receivable Individually Evaluated For Impairment Number Of Relationships FinancingReceivableIndividuallyEvaluatedForImpairmentNumberOfRelationships	0
CY2020Q4	us-gaap	Financing Receivable Recorded Investment Past Due FinancingReceivableRecordedInvestmentPastDue	27806000
CY2020Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	44647000
CY2020Q4	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	7426432000
CY2020Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	7498885000
CY2020Q4	us-gaap	Financing Receivable Nonaccrual No Allowance FinancingReceivableNonaccrualNoAllowance	0
CY2020	nbtb	Threshold Period Past Due For Loans To Be Considered Nonperforming ThresholdPeriodPastDueForLoansToBeConsideredNonperforming	P90D
CY2020	nbtb	Threshold Period Past Due For Loans To Be Considered Nonperforming ThresholdPeriodPastDueForLoansToBeConsideredNonperforming	P90D
CY2020Q4	us-gaap	Financing Receivable Originated In Current Fiscal Year FinancingReceivableOriginatedInCurrentFiscalYear	1927429000
CY2020Q4	us-gaap	Financing Receivable Originated In Fiscal Year Before Latest Fiscal Year FinancingReceivableOriginatedInFiscalYearBeforeLatestFiscalYear	1312819000
CY2020Q4	us-gaap	Financing Receivable Originated Two Years Before Latest Fiscal Year FinancingReceivableOriginatedTwoYearsBeforeLatestFiscalYear	949810000
CY2020Q4	us-gaap	Financing Receivable Originated Three Years Before Latest Fiscal Year FinancingReceivableOriginatedThreeYearsBeforeLatestFiscalYear	750728000
CY2020Q4	us-gaap	Financing Receivable Originated Four Years Before Latest Fiscal Year FinancingReceivableOriginatedFourYearsBeforeLatestFiscalYear	515688000
CY2019	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	55
CY2019	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	2606000
CY2018	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	28828000
CY2018Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	72505000
CY2019Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	72965000
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	0
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	72965000
CY2019Q4	nbtb	Financing Receivable Individually And Collectively Evaluated For Impairment FinancingReceivableIndividuallyAndCollectivelyEvaluatedForImpairment	7136098000
CY2020	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	37
CY2020	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	2900000
CY2020	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	3026000
CY2020	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	64
CY2020	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	3774000
CY2018Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	72505000
CY2019	us-gaap	Allowance For Loan And Lease Losses Write Offs AllowanceForLoanAndLeaseLossesWriteOffs	32540000
CY2019	us-gaap	Allowance For Loan And Lease Loss Recovery Of Bad Debts AllowanceForLoanAndLeaseLossRecoveryOfBadDebts	7588000
CY2019	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	25412000
CY2019Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	72965000
CY2017Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	69500000
CY2018	us-gaap	Allowance For Loan And Lease Losses Write Offs AllowanceForLoanAndLeaseLossesWriteOffs	34128000
CY2018	us-gaap	Allowance For Loan And Lease Loss Recovery Of Bad Debts AllowanceForLoanAndLeaseLossRecoveryOfBadDebts	8305000
CY2019Q4	us-gaap	Financing Receivable Recorded Investment Past Due FinancingReceivableRecordedInvestmentPastDue	34803000
CY2019Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	25174000
CY2019Q4	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	7076121000
CY2019Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	7136098000
CY2019Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	18253000
CY2019Q4	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	22541000
CY2019Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	0
CY2019	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	19733000
CY2019	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	891000
CY2018	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	20429000
CY2018	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	901000
CY2020Q4	nbtb	Financing Receivable Classified Grading Threshold Balance For Classified Loans To Be Individually Evaluated For Impairment FinancingReceivableClassifiedGradingThresholdBalanceForClassifiedLoansToBeIndividuallyEvaluatedForImpairment	1000000.0
CY2019Q3	nbtb	Financing Receivable Classified Grading Threshold Balance For Classified Loans To Be Individually Evaluated For Impairment FinancingReceivableClassifiedGradingThresholdBalanceForClassifiedLoansToBeIndividuallyEvaluatedForImpairment	750000
CY2019	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	37
CY2019	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	2508000
CY2019	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	2603000
CY2020Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	11735000
CY2020Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	180197000
CY2019Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	179910000
CY2020Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	105991000
CY2019Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	104279000
CY2020Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	74206000
CY2019Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	75631000
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	26400000
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	32800000
CY2019Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	34800000
CY2019Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	37300000
CY2020	us-gaap	Operating Lease Cost OperatingLeaseCost	7382000
CY2019	us-gaap	Operating Lease Cost OperatingLeaseCost	7239000
CY2020	us-gaap	Variable Lease Cost VariableLeaseCost	2141000
CY2019	us-gaap	Variable Lease Cost VariableLeaseCost	2231000
CY2020	us-gaap	Short Term Lease Cost ShortTermLeaseCost	453000
CY2019	us-gaap	Short Term Lease Cost ShortTermLeaseCost	356000
CY2020	us-gaap	Sublease Income SubleaseIncome	502000
CY2019	us-gaap	Sublease Income SubleaseIncome	448000
CY2020	us-gaap	Lease Cost LeaseCost	9474000
CY2019	us-gaap	Lease Cost LeaseCost	9378000
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	7209000
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	6339000
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	5251000
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	4581000
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	3411000
CY2020Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	36008000
CY2019Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	43574000
CY2020Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	3990000
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	32824000
CY2020Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P7Y2M15D
CY2019Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P7Y8M8D
CY2020Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0302
CY2019Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0300
CY2020	us-gaap	Operating Lease Payments OperatingLeasePayments	7934000
CY2019	us-gaap	Operating Lease Payments OperatingLeasePayments	6211000
CY2020	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	3441000
CY2019	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	41008000
CY2020	us-gaap	Operating Leases Rent Expense Net OperatingLeasesRentExpenseNet	8000000.0
CY2019	us-gaap	Operating Leases Rent Expense Net OperatingLeasesRentExpenseNet	8000000.0
CY2018	us-gaap	Operating Leases Rent Expense Net OperatingLeasesRentExpenseNet	8600000
CY2019Q4	us-gaap	Goodwill Goodwill	274769000
CY2020	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	5772000
CY2020Q4	us-gaap	Goodwill Goodwill	280541000
CY2018Q4	us-gaap	Goodwill Goodwill	274769000
CY2019	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	0
CY2019Q4	us-gaap	Goodwill Goodwill	274769000
CY2019	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0
CY2020	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0
CY2019Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	12020000
CY2020	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	3400000
CY2019	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	3600000
CY2018	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	4000000.0
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Next Twelve Months FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths	2800000
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	2200000
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	1800000
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	1500000
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Five FiniteLivedIntangibleAssetsAmortizationExpenseYearFive	1200000
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense After Year Five FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive	2300000
CY2020	us-gaap	Impairment Of Intangible Assets Finitelived ImpairmentOfIntangibleAssetsFinitelived	0
CY2019	us-gaap	Impairment Of Intangible Assets Finitelived ImpairmentOfIntangibleAssetsFinitelived	0
CY2020Q4	us-gaap	Time Deposit Maturities Year One TimeDepositMaturitiesYearOne	476983000
CY2020Q4	us-gaap	Time Deposit Maturities Year Two TimeDepositMaturitiesYearTwo	77081000
CY2020Q4	us-gaap	Time Deposit Maturities Year Three TimeDepositMaturitiesYearThree	36857000
CY2020Q4	us-gaap	Time Deposit Maturities Year Four TimeDepositMaturitiesYearFour	27888000
CY2020Q4	us-gaap	Time Deposit Maturities Year Five TimeDepositMaturitiesYearFive	14381000
CY2020Q4	us-gaap	Time Deposit Maturities After Year Five TimeDepositMaturitiesAfterYearFive	289000
CY2020Q4	us-gaap	Time Deposits TimeDeposits	633479000
CY2020Q4	nbtb	Time Deposits250000 Or More TimeDeposits250000OrMore	104100000
CY2019Q4	nbtb	Time Deposits250000 Or More TimeDeposits250000OrMore	140400000
CY2020Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	168400000
CY2019Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	655300000
CY2020Q4	us-gaap	Line Of Credit Facility Current Borrowing Capacity LineOfCreditFacilityCurrentBorrowingCapacity	3100000000
CY2019Q4	us-gaap	Line Of Credit Facility Current Borrowing Capacity LineOfCreditFacilityCurrentBorrowingCapacity	2400000000
CY2020Q4	us-gaap	Advances From Federal Home Loan Banks AdvancesFromFederalHomeLoanBanks	39097000
CY2019Q4	us-gaap	Advances From Federal Home Loan Banks AdvancesFromFederalHomeLoanBanks	64211000
CY2019Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due Within One Year Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueWithinOneYearOfBalanceSheetDate	25000000
CY2019Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Average Interest Rate Of Amounts Due Within One Year Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryAverageInterestRateOfAmountsDueWithinOneYearOfBalanceSheetDate	0.0234
CY2020Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due Within One Year Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueWithinOneYearOfBalanceSheetDate	25003000
CY2020Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Average Interest Rate Of Amounts Due Within One Year Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryAverageInterestRateOfAmountsDueWithinOneYearOfBalanceSheetDate	0.0256
CY2019Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due From One To Two Years Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromOneToTwoYearsOfBalanceSheetDate	25021000
CY2019Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Average Interest Rate One To Two Years From Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryAverageInterestRateOneToTwoYearsFromBalanceSheetDate	0.0256
CY2020Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due From One To Two Years Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromOneToTwoYearsOfBalanceSheetDate	10598000
CY2020Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Average Interest Rate One To Two Years From Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryAverageInterestRateOneToTwoYearsFromBalanceSheetDate	0.0253
CY2019Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due From Two To Three Years Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromTwoToThreeYearsOfBalanceSheetDate	10598000
CY2019Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Average Interest Rate Two To Three Years From Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryAverageInterestRateTwoToThreeYearsFromBalanceSheetDate	0.0253
CY2020Q4	nbtb	Federal Home Loan Bank Advances Maturities Summary Due From Ten To Eleven Years Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromTenToElevenYearsOfBalanceSheetDate	3496000
CY2020Q4	nbtb	Federal Home Loan Bank Advances Maturities Summary Average Interest Rate From Ten To Eleven Years Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryAverageInterestRateFromTenToElevenYearsOfBalanceSheetDate	0.0245
CY2019Q4	nbtb	Federal Home Loan Bank Advances Maturities Summary Due From Eleven To Twelve Years Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromElevenToTwelveYearsOfBalanceSheetDate	3592000
CY2019Q4	nbtb	Federal Home Loan Bank Advances Maturities Summary Average Interest Rate Eleven To Twelve Years From Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryAverageInterestRateElevenToTwelveYearsFromBalanceSheetDate	0.0245
CY2020Q4	nbtb	Number Of Statutory Business Trusts Included In Trusts NumberOfStatutoryBusinessTrustsIncludedInTrusts	5
CY2020Q4	nbtb	Minimum Assets For Bank Holding Companies To Be Subject To Same Capital Requirements As Insured Depository Institutions MinimumAssetsForBankHoldingCompaniesToBeSubjectToSameCapitalRequirementsAsInsuredDepositoryInstitutions	500000000
CY2020Q4	nbtb	Deferred Tax Assets Tax Deferred Expense Loan Fees DeferredTaxAssetsTaxDeferredExpenseLoanFees	5400000
CY2019Q4	nbtb	Deferred Tax Assets Tax Deferred Expense Loan Fees DeferredTaxAssetsTaxDeferredExpenseLoanFees	1384000
CY2020Q4	us-gaap	Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Weighted Average Interest Crediting Rate DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationWeightedAverageInterestCreditingRate	0.0162
CY2019Q4	us-gaap	Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Weighted Average Interest Crediting Rate DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationWeightedAverageInterestCreditingRate	0.0228
CY2018Q4	us-gaap	Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Weighted Average Interest Crediting Rate DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationWeightedAverageInterestCreditingRate	0.0336
CY2020	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Weighted Average Interest Crediting Rate DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostWeightedAverageInterestCreditingRate	0.0228
CY2019	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Weighted Average Interest Crediting Rate DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostWeightedAverageInterestCreditingRate	0.0336
CY2018	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Weighted Average Interest Crediting Rate DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostWeightedAverageInterestCreditingRate	0.0280
CY2020	us-gaap	Other Postretirement Benefit Expense OtherPostretirementBenefitExpense	200000
CY2019	us-gaap	Other Postretirement Benefit Expense OtherPostretirementBenefitExpense	100000
CY2018	us-gaap	Other Postretirement Benefit Expense OtherPostretirementBenefitExpense	100000
CY2020Q4	us-gaap	Common Equity Tier One Capital Ratio CommonEquityTierOneCapitalRatio	0.1184
CY2018Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-43174000
CY2020	nbtb	Preceding Period Of Retained Net Profits For Approval Of Office Of Comptroller Of Currency PrecedingPeriodOfRetainedNetProfitsForApprovalOfOfficeOfComptrollerOfCurrency	P2Y
CY2020	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	8000000.0
CY2020	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	30.28
CY2020Q4	us-gaap	Statutory Accounting Practices Statutory Amount Available For Dividend Payments StatutoryAccountingPracticesStatutoryAmountAvailableForDividendPayments	194200000
CY2020	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	263507
CY2020Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	417000
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-19026000
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Available For Grant ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant	781123
CY2020Q4	us-gaap	Accumulated Other Comprehensive Income Loss Defined Benefit Pension And Other Postretirement Plans Net Of Tax AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax	20134000
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Defined Benefit Pension And Other Postretirement Plans Net Of Tax AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax	21677000
CY2018Q4	us-gaap	Accumulated Other Comprehensive Income Loss Defined Benefit Pension And Other Postretirement Plans Net Of Tax AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax	27689000
CY2020Q4	us-gaap	Accumulated Other Comprehensive Income Loss Cumulative Changes In Net Gain Loss From Cash Flow Hedges Effect Net Of Tax AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax	-16000
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Cumulative Changes In Net Gain Loss From Cash Flow Hedges Effect Net Of Tax AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax	-32000
CY2018Q4	us-gaap	Accumulated Other Comprehensive Income Loss Cumulative Changes In Net Gain Loss From Cash Flow Hedges Effect Net Of Tax AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax	1821000
CY2020Q4	us-gaap	Accumulated Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	20567000
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	2683000
CY2018Q4	us-gaap	Accumulated Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-17306000
CY2020Q4	us-gaap	Stock Repurchase Program Remaining Number Of Shares Authorized To Be Repurchased StockRepurchaseProgramRemainingNumberOfSharesAuthorizedToBeRepurchased	736493
CY2020Q4	us-gaap	Stock Repurchase Program Number Of Shares Authorized To Be Repurchased StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased	1000000
CY2020	nbtb	Permissible Capital Transition Relief Period PermissibleCapitalTransitionReliefPeriod	P5Y
CY2020Q4	us-gaap	Tier One Leverage Capital TierOneLeverageCapital	1018320000
CY2020Q4	us-gaap	Tier One Leverage Capital To Average Assets TierOneLeverageCapitalToAverageAssets	0.0956
CY2020Q4	us-gaap	Tier One Leverage Capital Required For Capital Adequacy To Average Assets TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets	0.0400
CY2020Q4	us-gaap	Tier One Leverage Capital Required To Be Well Capitalized To Average Assets TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets	0.0500
CY2020Q4	us-gaap	Common Equity Tier One Capital CommonEquityTierOneCapital	921320000
CY2020Q4	us-gaap	Banking Regulation Common Equity Tier One Risk Based Capital Ratio Capital Adequacy Minimum BankingRegulationCommonEquityTierOneRiskBasedCapitalRatioCapitalAdequacyMinimum	0.0450
CY2020Q4	nbtb	Common Equity Tier One Risk Based Capital To Risk Weighted Assets Required For Capital Adequacy Plus Buffer CommonEquityTierOneRiskBasedCapitalToRiskWeightedAssetsRequiredForCapitalAdequacyPlusBuffer	0.0700
CY2020Q4	us-gaap	Banking Regulation Common Equity Tier One Risk Based Capital Ratio Well Capitalized Minimum BankingRegulationCommonEquityTierOneRiskBasedCapitalRatioWellCapitalizedMinimum	0.0650
CY2020Q4	nbtb	Tier One Risk Based Capital Required For Capital Adequacy Plus Buffer To Risk Weighted Assets TierOneRiskBasedCapitalRequiredForCapitalAdequacyPlusBufferToRiskWeightedAssets	0.0850
CY2020Q4	us-gaap	Tier One Risk Based Capital TierOneRiskBasedCapital	1018320000
CY2020Q4	us-gaap	Tier One Risk Based Capital To Risk Weighted Assets TierOneRiskBasedCapitalToRiskWeightedAssets	0.1309
CY2020Q4	us-gaap	Tier One Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets	0.0600
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	43693000
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.39
CY2019	us-gaap	Net Income Loss NetIncomeLoss	121021000
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	43815000
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.76
CY2020Q4	us-gaap	Tier One Risk Based Capital Required To Be Well Capitalized To Risk Weighted Assets TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets	0.0800
CY2020Q4	us-gaap	Capital Capital	1215672000
CY2020Q4	us-gaap	Capital To Risk Weighted Assets CapitalToRiskWeightedAssets	0.1562
CY2020Q4	us-gaap	Capital Required For Capital Adequacy To Risk Weighted Assets CapitalRequiredForCapitalAdequacyToRiskWeightedAssets	0.0800
CY2020Q4	nbtb	Capital Required For Capital Adequacy Plus Buffer To Risk Weighted Assets CapitalRequiredForCapitalAdequacyPlusBufferToRiskWeightedAssets	0.1050
CY2020Q4	us-gaap	Capital Required To Be Well Capitalized To Risk Weighted Assets CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets	0.1000
CY2019Q4	us-gaap	Tier One Leverage Capital TierOneLeverageCapital	963147000
CY2019Q4	us-gaap	Tier One Leverage Capital To Average Assets TierOneLeverageCapitalToAverageAssets	0.1033
CY2019Q4	us-gaap	Tier One Leverage Capital Required For Capital Adequacy To Average Assets TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets	0.0400
CY2019Q4	us-gaap	Tier One Leverage Capital Required To Be Well Capitalized To Average Assets TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets	0.0500
CY2019Q4	us-gaap	Common Equity Tier One Capital CommonEquityTierOneCapital	866147000
CY2019Q4	us-gaap	Common Equity Tier One Capital Ratio CommonEquityTierOneCapitalRatio	0.1129
CY2019Q4	us-gaap	Banking Regulation Common Equity Tier One Risk Based Capital Ratio Capital Adequacy Minimum BankingRegulationCommonEquityTierOneRiskBasedCapitalRatioCapitalAdequacyMinimum	0.0450
CY2019Q4	nbtb	Common Equity Tier One Risk Based Capital To Risk Weighted Assets Required For Capital Adequacy Plus Buffer CommonEquityTierOneRiskBasedCapitalToRiskWeightedAssetsRequiredForCapitalAdequacyPlusBuffer	0.0700
CY2019Q4	us-gaap	Banking Regulation Common Equity Tier One Risk Based Capital Ratio Well Capitalized Minimum BankingRegulationCommonEquityTierOneRiskBasedCapitalRatioWellCapitalizedMinimum	0.0650
CY2019Q4	us-gaap	Tier One Risk Based Capital TierOneRiskBasedCapital	963147000
CY2019Q4	us-gaap	Tier One Risk Based Capital To Risk Weighted Assets TierOneRiskBasedCapitalToRiskWeightedAssets	0.1256
CY2019Q4	us-gaap	Tier One Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets	0.0600
CY2019Q4	nbtb	Tier One Risk Based Capital Required For Capital Adequacy Plus Buffer To Risk Weighted Assets TierOneRiskBasedCapitalRequiredForCapitalAdequacyPlusBufferToRiskWeightedAssets	0.0850
CY2019Q4	us-gaap	Tier One Risk Based Capital Required To Be Well Capitalized To Risk Weighted Assets TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets	0.0800
CY2019Q4	us-gaap	Capital Capital	1037041000
CY2019Q4	us-gaap	Capital To Risk Weighted Assets CapitalToRiskWeightedAssets	0.1352
CY2019Q4	us-gaap	Capital Required For Capital Adequacy To Risk Weighted Assets CapitalRequiredForCapitalAdequacyToRiskWeightedAssets	0.0800
CY2019Q4	nbtb	Capital Required For Capital Adequacy Plus Buffer To Risk Weighted Assets CapitalRequiredForCapitalAdequacyPlusBufferToRiskWeightedAssets	0.1050
CY2019Q4	us-gaap	Capital Required To Be Well Capitalized To Risk Weighted Assets CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets	0.1000
CY2020	us-gaap	Net Income Loss NetIncomeLoss	104388000
CY2018	us-gaap	Net Income Loss NetIncomeLoss	112566000
CY2018	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	43701000
CY2018	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.58
CY2020	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	296000
CY2019	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	309000
CY2018	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	319000
CY2020	us-gaap	Net Income Loss NetIncomeLoss	104388000
CY2020	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	43989000
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.37
CY2019	us-gaap	Net Income Loss NetIncomeLoss	121021000
CY2019	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	44124000
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.74
CY2018	us-gaap	Net Income Loss NetIncomeLoss	112566000
CY2018	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	44020000
CY2018	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.56
CY2020Q4	nbtb	Loans And Leases Receivable Collateral Dependent Loans Specific Reserves LoansAndLeasesReceivableCollateralDependentLoansSpecificReserves	3200000
CY2019Q4	nbtb	Loans And Leases Receivable Collateral Dependent Loans LoansAndLeasesReceivableCollateralDependentLoans	0
CY2020Q4	nbtb	Loans And Leases Receivable Collateral Dependent Loans LoansAndLeasesReceivableCollateralDependentLoans	15200000
CY2020Q4	nbtb	Percentage Of Companys Loans Secured By Real Estate PercentageOfCompanysLoansSecuredByRealEstate	0.59
CY2020	nbtb	Guarantor Obligations Period GuarantorObligationsPeriod	P1Y
CY2020	nbtb	Maintenance Period Basis Federal Reserve Bank MaintenancePeriodBasisFederalReserveBank	P14D
CY2020Q4	nbtb	Average Reserve Balances With Federal Reserve Bank AverageReserveBalancesWithFederalReserveBank	64600000

Files In Submission

Name	View Source	Status
0001140361-21-006657-index-headers.html	Edgar Link	pending
0001140361-21-006657-index.html	Edgar Link	pending
0001140361-21-006657.txt	Edgar Link	pending
0001140361-21-006657-xbrl.zip	Edgar Link	pending
brhc10020564_10k.htm	Edgar Link	pending
brhc10020564_10k_htm.xml	Edgar Link	completed
ex21.htm	Edgar Link	pending
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2019 Q4 Form 10-K Financial Statement

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$NBTB NBT BANCORP INC Stock $nbtb

2019 Q4 Form 10-K Financial Statement

#000114036121006657 Filed on March 01, 2021

Income Statement

Balance Sheet

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Files In Submission

$NBTB
NBT BANCORP INC Stock $nbtb