XML 14 R33.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Allowance for Loan Losses and Credit Quality of Loans, Past Due Loans (Details) (USD $) In Thousands, unless otherwise specified | 3 Months Ended |
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Mar. 31, 2015 | Dec. 31, 2014
Financing Receivable, Recorded Investment, Aging [Abstract] |  |
Minimum number of days past due for nonaccrual loan status | 90 days |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
31 - 60 Days Past Due Accruing | $ 22,234 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue | $ 27,402 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue
61 - 90 Days Past Due Accruing | 5,475 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue | 6,150 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue
Greater Than 90 Days Past Due Accruing | 2,601 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue | 4,941 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue
Total Past Due Accruing | 30,310 us-gaap_FinancingReceivableRecordedInvestmentPastDue | 38,493 us-gaap_FinancingReceivableRecordedInvestmentPastDue
Non-Accrual | 45,053 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus | 41,074 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
Current | 5,547,660 us-gaap_FinancingReceivableRecordedInvestmentCurrent | 5,515,704 us-gaap_FinancingReceivableRecordedInvestmentCurrent
Ending balance of loans | 5,623,023 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome | 5,595,271 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
Commercial Loans [Member] |  |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
Ending balance of loans | 2,484,300 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 2,473,702 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Consumer Loans [Member] |  |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
Ending balance of loans | 2,013,123 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 2,005,980 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
Residential Real Estate Mortgages [Member] |  |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
Ending balance of loans | 1,125,600 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 1,115,589 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember
Originated Loans [Member] |  |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
31 - 60 Days Past Due Accruing | 20,089 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember | 25,496 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember
61 - 90 Days Past Due Accruing | 4,725 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember | 5,805 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember
Greater Than 90 Days Past Due Accruing | 2,560 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember | 4,204 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember
Total Past Due Accruing | 27,374 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember | 35,505 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember
Non-Accrual | 31,099 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember | 30,845 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember
Current | 4,845,780 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember | 4,781,587 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember
Ending balance of loans | 4,904,253 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember | 4,847,937 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember
Originated Loans [Member] | Commercial Loans [Member] |  |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
31 - 60 Days Past Due Accruing | 1,219 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 1,010 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
61 - 90 Days Past Due Accruing | 229 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 970 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Greater Than 90 Days Past Due Accruing | 77 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 84 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Total Past Due Accruing | 1,525 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 2,064 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Non-Accrual | 15,235 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 13,431 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Current | 2,142,302 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 2,124,876 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Ending balance of loans | 2,159,062 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 2,140,371 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Originated Loans [Member] | Commercial [Member] |  |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
31 - 60 Days Past Due Accruing | 348 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember | 0 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember
61 - 90 Days Past Due Accruing | 0 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember | 735 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember
Greater Than 90 Days Past Due Accruing | 35 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember | 0 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember
Total Past Due Accruing | 383 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember | 735 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember
Non-Accrual | 1,019 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember | 1,012 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember
Current | 620,111 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember | 613,400 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember
Ending balance of loans | 621,513 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember | 615,147 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember
Originated Loans [Member] | Commercial Real Estate [Member] |  |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
31 - 60 Days Past Due Accruing | 133 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember | 192 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember
61 - 90 Days Past Due Accruing | 37 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember | 0 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember
Greater Than 90 Days Past Due Accruing | 0 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember | 0 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember
Total Past Due Accruing | 170 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember | 192 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember
Non-Accrual | 6,231 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember | 4,127 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember
Current | 1,076,218 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember | 1,064,549 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember
Ending balance of loans | 1,082,619 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember | 1,068,868 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember
Originated Loans [Member] | Agricultural [Member] |  |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
31 - 60 Days Past Due Accruing | 129 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalFinancingReceivableMember | 0 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalFinancingReceivableMember
61 - 90 Days Past Due Accruing | 0 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalFinancingReceivableMember | 0 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalFinancingReceivableMember
Greater Than 90 Days Past Due Accruing | 0 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalFinancingReceivableMember | 0 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalFinancingReceivableMember
Total Past Due Accruing | 129 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalFinancingReceivableMember | 0 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalFinancingReceivableMember
Non-Accrual | 800 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalFinancingReceivableMember | 817 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalFinancingReceivableMember
Current | 31,080 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalFinancingReceivableMember | 32,130 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalFinancingReceivableMember
Ending balance of loans | 32,009 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalFinancingReceivableMember | 32,947 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalFinancingReceivableMember
Originated Loans [Member] | Agricultural Real Estate [Member] |  |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
31 - 60 Days Past Due Accruing | 7 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalRealEstateFinancingReceivableMember | 19 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalRealEstateFinancingReceivableMember
61 - 90 Days Past Due Accruing | 0 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalRealEstateFinancingReceivableMember | 0 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalRealEstateFinancingReceivableMember
Greater Than 90 Days Past Due Accruing | 0 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalRealEstateFinancingReceivableMember | 0 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalRealEstateFinancingReceivableMember
Total Past Due Accruing | 7 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalRealEstateFinancingReceivableMember | 19 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalRealEstateFinancingReceivableMember
Non-Accrual | 561 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalRealEstateFinancingReceivableMember | 565 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalRealEstateFinancingReceivableMember
Current | 23,963 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalRealEstateFinancingReceivableMember | 24,390 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalRealEstateFinancingReceivableMember
Ending balance of loans | 24,531 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalRealEstateFinancingReceivableMember | 24,974 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalRealEstateFinancingReceivableMember
Originated Loans [Member] | Business Banking [Member] |  |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
31 - 60 Days Past Due Accruing | 602 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember | 799 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember
61 - 90 Days Past Due Accruing | 192 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember | 235 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember
Greater Than 90 Days Past Due Accruing | 42 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember | 84 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember
Total Past Due Accruing | 836 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember | 1,118 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember
Non-Accrual | 6,624 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember | 6,910 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember
Current | 390,930 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember | 390,407 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember
Ending balance of loans | 398,390 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember | 398,435 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember
Originated Loans [Member] | Consumer Loans [Member] |  |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
31 - 60 Days Past Due Accruing | 15,676 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 21,585 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
61 - 90 Days Past Due Accruing | 3,232 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 4,739 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
Greater Than 90 Days Past Due Accruing | 2,228 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 2,864 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
Total Past Due Accruing | 21,136 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 29,188 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
Non-Accrual | 8,346 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 8,644 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
Current | 1,850,966 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 1,820,892 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
Ending balance of loans | 1,880,448 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 1,858,724 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
Originated Loans [Member] | Indirect [Member] |  |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
31 - 60 Days Past Due Accruing | 11,794 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember | 16,434 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember
61 - 90 Days Past Due Accruing | 2,348 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember | 3,154 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember
Greater Than 90 Days Past Due Accruing | 1,722 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember | 1,991 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember
Total Past Due Accruing | 15,864 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember | 21,579 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember
Non-Accrual | 2,056 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember | 1,964 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember
Current | 1,327,653 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember | 1,286,507 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember
Ending balance of loans | 1,345,573 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember | 1,310,050 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember
Originated Loans [Member] | Home Equity Member] |  |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
31 - 60 Days Past Due Accruing | 3,507 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember | 4,591 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember
61 - 90 Days Past Due Accruing | 804 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember | 1,428 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember
Greater Than 90 Days Past Due Accruing | 484 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember | 821 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember
Total Past Due Accruing | 4,795 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember | 6,840 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember
Non-Accrual | 6,160 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember | 6,596 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember
Current | 470,340 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember | 479,444 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember
Ending balance of loans | 481,295 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember | 492,880 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember
Originated Loans [Member] | Direct [Member] |  |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
31 - 60 Days Past Due Accruing | 375 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember | 560 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember
61 - 90 Days Past Due Accruing | 80 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember | 157 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember
Greater Than 90 Days Past Due Accruing | 22 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember | 52 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember
Total Past Due Accruing | 477 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember | 769 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember
Non-Accrual | 130 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember | 84 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember
Current | 52,973 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember | 54,941 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember
Ending balance of loans | 53,580 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember | 55,794 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember
Originated Loans [Member] | Residential Real Estate Mortgages [Member] |  |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
31 - 60 Days Past Due Accruing | 3,194 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 2,901 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember
61 - 90 Days Past Due Accruing | 1,264 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 96 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember
Greater Than 90 Days Past Due Accruing | 255 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 1,256 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember
Total Past Due Accruing | 4,713 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 4,253 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember
Non-Accrual | 7,518 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 8,770 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember
Current | 852,512 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 835,819 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember
Ending balance of loans | 864,743 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 848,842 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember
Acquired Loans [Member] |  |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
31 - 60 Days Past Due Accruing | 2,145 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember | 1,906 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember
61 - 90 Days Past Due Accruing | 750 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember | 345 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember
Greater Than 90 Days Past Due Accruing | 41 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember | 737 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember
Total Past Due Accruing | 2,936 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember | 2,988 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember
Non-Accrual | 13,954 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember | 10,229 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember
Current | 701,880 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember | 734,117 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember
Ending balance of loans | 718,770 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember | 747,334 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember
Acquired Loans [Member] | Commercial Loans [Member] |  |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
31 - 60 Days Past Due Accruing | 42 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 5 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
61 - 90 Days Past Due Accruing | 2 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 15 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Greater Than 90 Days Past Due Accruing | 0 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 0 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Total Past Due Accruing | 44 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 20 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Non-Accrual | 10,252 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 6,340 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Current | 314,942 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 326,971 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Ending balance of loans | 325,238 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 333,331 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Acquired Loans [Member] | Commercial [Member] |  |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
31 - 60 Days Past Due Accruing | 42 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember | 0 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember
61 - 90 Days Past Due Accruing | 0 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember | 0 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember
Greater Than 90 Days Past Due Accruing | 0 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember | 0 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember
Total Past Due Accruing | 42 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember | 0 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember
Non-Accrual | 2,517 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember | 3,009 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember
Current | 70,010 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember | 72,255 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember
Ending balance of loans | 72,569 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember | 75,264 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember
Acquired Loans [Member] | Commercial Real Estate [Member] |  |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
31 - 60 Days Past Due Accruing | 0 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember | 0 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember
61 - 90 Days Past Due Accruing | 0 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember | 0 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember
Greater Than 90 Days Past Due Accruing | 0 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember | 0 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember
Total Past Due Accruing | 0 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember | 0 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember
Non-Accrual | 7,247 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember | 2,666 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember
Current | 190,518 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember | 197,222 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember
Ending balance of loans | 197,765 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember | 199,888 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember
Acquired Loans [Member] | Business Banking [Member] |  |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
31 - 60 Days Past Due Accruing | 0 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember | 5 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember
61 - 90 Days Past Due Accruing | 2 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember | 15 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember
Greater Than 90 Days Past Due Accruing | 0 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember | 0 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember
Total Past Due Accruing | 2 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember | 20 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember
Non-Accrual | 488 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember | 665 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember
Current | 54,414 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember | 57,494 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember
Ending balance of loans | 54,904 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember | 58,179 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember
Acquired Loans [Member] | Consumer Loans [Member] |  |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
31 - 60 Days Past Due Accruing | 631 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 739 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
61 - 90 Days Past Due Accruing | 98 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 65 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
Greater Than 90 Days Past Due Accruing | 41 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 66 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
Total Past Due Accruing | 770 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 870 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
Non-Accrual | 601 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 696 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
Current | 131,304 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 145,690 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
Ending balance of loans | 132,675 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 147,256 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
Acquired Loans [Member] | Indirect [Member] |  |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
31 - 60 Days Past Due Accruing | 343 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember | 518 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember
61 - 90 Days Past Due Accruing | 44 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember | 5 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember
Greater Than 90 Days Past Due Accruing | 37 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember | 54 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember
Total Past Due Accruing | 424 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember | 577 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember
Non-Accrual | 146 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember | 106 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember
Current | 53,577 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember | 64,540 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember
Ending balance of loans | 54,147 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember | 65,223 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember
Acquired Loans [Member] | Home Equity Member] |  |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
31 - 60 Days Past Due Accruing | 212 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember | 190 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember
61 - 90 Days Past Due Accruing | 50 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember | 60 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember
Greater Than 90 Days Past Due Accruing | 0 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember | 5 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember
Total Past Due Accruing | 262 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember | 255 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember
Non-Accrual | 427 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember | 557 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember
Current | 73,029 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember | 75,904 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember
Ending balance of loans | 73,718 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember | 76,716 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember
Acquired Loans [Member] | Direct [Member] |  |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
31 - 60 Days Past Due Accruing | 76 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember | 31 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember
61 - 90 Days Past Due Accruing | 4 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember | 0 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember
Greater Than 90 Days Past Due Accruing | 4 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember | 7 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember
Total Past Due Accruing | 84 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember | 38 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember
Non-Accrual | 28 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember | 33 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember
Current | 4,698 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember | 5,246 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember
Ending balance of loans | 4,810 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember | 5,317 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember
Acquired Loans [Member] | Residential Real Estate Mortgages [Member] |  |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
31 - 60 Days Past Due Accruing | 1,472 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 1,162 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember
61 - 90 Days Past Due Accruing | 650 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 265 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember
Greater Than 90 Days Past Due Accruing | 0 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 671 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember
Total Past Due Accruing | 2,122 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 2,098 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember
Non-Accrual | 3,101 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 3,193 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember
Current | 255,634 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 261,456 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember
Ending balance of loans | $ 260,857 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | $ 266,747 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember

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- Definition Financing receivables that are current. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 7A -URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953401-111524 + Details
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- Definition Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5074-111524 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=28367877&loc=d3e4428-111522 + Details
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