XML 74 R58.htm IDEA: XBRL DOCUMENT
v3.22.0.1

Summary of Significant Accounting Policies, Allowance for Credit Losses - Loans (Details) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2021 USD ($) Loan | Dec. 31, 2020 USD ($) Loan
Minimum [Member] |  |
Allowance for Credit Losses [Abstract] |  |
Threshold period past due for loans to be written off | 90 days |
Maximum [Member] |  |
Allowance for Credit Losses [Abstract] |  |
Threshold period past due for loans to be written off | 120 days |
Paycheck Protection Program [Member] |  |
Allowance for Credit Losses [Abstract] |  |
Number of loans processed | Loan | 3,100 | 3,000
Amount of loans processed | $ 287.0 |
Number of loans on which payments were received | Loan | 4,505 | 214
Amount of loan payments received | $ 632.4 | $ 72.7
Paycheck Protection Program [Member] | Minimum [Member] |  |
Allowance for Credit Losses [Abstract] |  |
Amount of loans processed |  | $ 548.0
Commercial Loans [Member] | Commercial Real Estate [Member] | Maximum [Member] |  |
Allowance for Credit Losses [Abstract] |  |
Loan amount, percentage of appraised value or purchase price of the property | 80.00% |
Consumer Loans [Member] | Auto [Member] | Minimum [Member] |  |
Allowance for Credit Losses [Abstract] |  |
Principal repayment term of loan | 3 years |
Consumer Loans [Member] | Auto [Member] | Maximum [Member] |  |
Allowance for Credit Losses [Abstract] |  |
Principal repayment term of loan | 6 years |
Consumer Loans [Member] | Installment Loans [Member] | Minimum [Member] |  |
Allowance for Credit Losses [Abstract] |  |
Principal repayment term of loan | 1 year |
Consumer Loans [Member] | Installment Loans [Member] | Maximum [Member] |  |
Allowance for Credit Losses [Abstract] |  |
Principal repayment term of loan | 15 years |
Residential [Member] | Maximum [Member] |  |
Allowance for Credit Losses [Abstract] |  |
Loan amount, percentage of appraised value or purchase price of the property | 85.00% |
Residential [Member] | Home Equity [Member] | Maximum [Member] |  |
Allowance for Credit Losses [Abstract] |  |
Loan amount, percentage of equity in property | 85.00% |
Term of draw | 10 years |
Term of amortization | 15 years |

X
- Definition Represents the amortization term of the financing receivable, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | nbtb_FinancingReceivableAmortizationTerm
Namespace Prefix: | nbtb_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of financing receivables processed. + References No definition available. + Details
Name: | nbtb_FinancingReceivableAmountOfLoansProcessed
Namespace Prefix: | nbtb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Number of financing receivables processed. + References No definition available. + Details
Name: | nbtb_FinancingReceivableNumberOfLoansProcessed
Namespace Prefix: | nbtb_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of loan payments received during the period. + References No definition available. + Details
Name: | nbtb_FinancingReceivablePaymentsReceived
Namespace Prefix: | nbtb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Number of financing receivables on which payments were received during the period. + References No definition available. + Details
Name: | nbtb_FinancingReceivablePaymentsReceivedNumberOfLoans
Namespace Prefix: | nbtb_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the principal repayment term of the financing receivable, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | nbtb_FinancingReceivablePrincipalRepaymentTerm
Namespace Prefix: | nbtb_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the draw term of the financing receivable, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | nbtb_FinancingReceivableTermOfDraw
Namespace Prefix: | nbtb_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition This element represents the percentage of the appraised value or purchase price of a property for the originated amounts of loans. + References No definition available. + Details
Name: | nbtb_LoanOriginationAmountPercentageOfAppraisedValueOrPurchasePriceOfProperty
Namespace Prefix: | nbtb_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition This element represents the percentage of the equity in a property for the originated amounts of loans. + References No definition available. + Details
Name: | nbtb_LoanOriginationAmountPercentageOfEquityInProperty
Namespace Prefix: | nbtb_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The threshold period past due for a loan to be written off, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | nbtb_ThresholdPeriodPastDueForLoansToBeWrittenOff
Namespace Prefix: | nbtb_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_AllowanceForCreditLossAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LoansInsuredOrGuaranteedByGovernmentAuthoritiesAxis=nbtb_SmallBusinessAdministrationSBACARESActPaycheckProtectionProgramMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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

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

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

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

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