XML 92 R58.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 | 12 Months Ended |
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Dec. 31, 2014 | Dec. 31, 2013
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 | $ 27,402 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue | $ 31,961 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue
61 - 90 Days Past Due Accruing | 6,150 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue | 5,894 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue
Greater Than 90 Days Past Due Accruing | 4,941 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue | 3,737 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue
Total Past Due Accruing | 38,493 us-gaap_FinancingReceivableRecordedInvestmentPastDue | 41,592 us-gaap_FinancingReceivableRecordedInvestmentPastDue
Non-Accrual | 41,074 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus | 49,965 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
Current | 5,515,704 us-gaap_FinancingReceivableRecordedInvestmentCurrent | 5,315,238 us-gaap_FinancingReceivableRecordedInvestmentCurrent
Recorded Total Loans and Leases | 5,595,271 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome | 5,406,795 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
Commercial Loans [Member] |  |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
Recorded Total Loans and Leases | 2,473,702 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 2,392,621 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Consumer Loans [Member] |  |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
Recorded Total Loans and Leases | 2,005,980 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 1,972,537 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
Residential Real Estate Mortgages [Member] |  |
Financing Receivable, Recorded Investment, Past Due [Abstract] |  |
Recorded Total Loans and Leases | 1,115,589 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 1,041,637 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 | 25,496 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember | 28,124 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember
61 - 90 Days Past Due Accruing | 5,805 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember | 5,660 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember
Greater Than 90 Days Past Due Accruing | 4,204 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember | 3,657 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember
Total Past Due Accruing | 35,505 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember | 37,441 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember
Non-Accrual | 30,845 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember | 33,883 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember
Current | 4,781,587 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember | 4,405,079 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember
Recorded Total Loans and Leases | 4,847,937 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember | 4,476,403 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 | 1,010 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 3,368 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
61 - 90 Days Past Due Accruing | 970 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 390 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Greater Than 90 Days Past Due Accruing | 84 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 105 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Total Past Due Accruing | 2,064 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 3,863 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Non-Accrual | 13,431 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 19,300 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Current | 2,124,876 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 1,967,069 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Recorded Total Loans and Leases | 2,140,371 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 1,990,232 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 | 0 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember | 105 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember
61 - 90 Days Past Due Accruing | 735 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember | 247 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember
Greater Than 90 Days Past Due Accruing | 0 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 | 735 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember | 352 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember
Non-Accrual | 1,012 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember | 3,669 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember
Current | 613,400 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember | 612,402 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember
Recorded Total Loans and Leases | 615,147 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember | 616,423 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 | 192 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember | 1,366 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember
61 - 90 Days Past Due Accruing | 0 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 | 192 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember | 1,366 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember
Non-Accrual | 4,127 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember | 7,834 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember
Current | 1,064,549 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember | 925,116 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember
Recorded Total Loans and Leases | 1,068,868 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember | 934,316 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 | 0 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalFinancingReceivableMember | 150 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 | 21 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 | 0 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalFinancingReceivableMember | 171 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalFinancingReceivableMember
Non-Accrual | 817 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalFinancingReceivableMember | 1,135 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalFinancingReceivableMember
Current | 32,130 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalFinancingReceivableMember | 63,856 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalFinancingReceivableMember
Recorded Total Loans and Leases | 32,947 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalFinancingReceivableMember | 65,162 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 | 19 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalRealEstateFinancingReceivableMember | 519 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 | 19 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalRealEstateFinancingReceivableMember | 519 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalRealEstateFinancingReceivableMember
Non-Accrual | 565 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalRealEstateFinancingReceivableMember | 961 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalRealEstateFinancingReceivableMember
Current | 24,390 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalRealEstateFinancingReceivableMember | 35,172 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalRealEstateFinancingReceivableMember
Recorded Total Loans and Leases | 24,974 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_AgriculturalRealEstateFinancingReceivableMember | 36,652 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 | 799 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember | 1,228 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember
61 - 90 Days Past Due Accruing | 235 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember | 122 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember
Greater Than 90 Days Past Due Accruing | 84 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember | 105 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember
Total Past Due Accruing | 1,118 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember | 1,455 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember
Non-Accrual | 6,910 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember | 5,701 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember
Current | 390,407 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember | 330,523 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember
Recorded Total Loans and Leases | 398,435 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember | 337,679 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 | 21,585 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 20,805 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
61 - 90 Days Past Due Accruing | 4,739 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 4,891 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
Greater Than 90 Days Past Due Accruing | 2,864 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 2,744 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
Total Past Due Accruing | 29,188 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 28,440 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
Non-Accrual | 8,644 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 7,478 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
Current | 1,820,892 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 1,717,032 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
Recorded Total Loans and Leases | 1,858,724 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 1,752,950 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 | 16,434 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember | 14,093 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember
61 - 90 Days Past Due Accruing | 3,154 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember | 2,878 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember
Greater Than 90 Days Past Due Accruing | 1,991 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember | 1,583 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember
Total Past Due Accruing | 21,579 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember | 18,554 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember
Non-Accrual | 1,964 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember | 1,461 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember
Current | 1,286,507 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember | 1,141,829 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember
Recorded Total Loans and Leases | 1,310,050 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember | 1,161,844 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 | 4,591 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember | 6,033 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember
61 - 90 Days Past Due Accruing | 1,428 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember | 1,888 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember
Greater Than 90 Days Past Due Accruing | 821 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember | 1,115 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember
Total Past Due Accruing | 6,840 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember | 9,036 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember
Non-Accrual | 6,596 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember | 5,931 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember
Current | 479,444 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember | 517,856 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember
Recorded Total Loans and Leases | 492,880 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember | 532,823 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 | 560 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember | 679 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember
61 - 90 Days Past Due Accruing | 157 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember | 125 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember
Greater Than 90 Days Past Due Accruing | 52 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember | 46 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember
Total Past Due Accruing | 769 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember | 850 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember
Non-Accrual | 84 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember | 86 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember
Current | 54,941 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember | 57,347 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember
Recorded Total Loans and Leases | 55,794 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember | 58,283 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 | 2,901 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 3,951 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember
61 - 90 Days Past Due Accruing | 96 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 379 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember
Greater Than 90 Days Past Due Accruing | 1,256 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 808 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember
Total Past Due Accruing | 4,253 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 5,138 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember
Non-Accrual | 8,770 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 7,105 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember
Current | 835,819 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 720,978 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember
Recorded Total Loans and Leases | 848,842 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_OriginatedLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 733,221 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 | 1,906 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember | 3,837 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember
61 - 90 Days Past Due Accruing | 345 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember | 234 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember
Greater Than 90 Days Past Due Accruing | 737 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember | 80 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember
Total Past Due Accruing | 2,988 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember | 4,151 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember
Non-Accrual | 10,229 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember | 16,082 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember
Current | 734,117 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember | 910,159 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember
Recorded Total Loans and Leases | 747,334 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember | 930,392 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 | 5 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 344 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
61 - 90 Days Past Due Accruing | 15 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 2 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 | 20 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 346 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Non-Accrual | 6,340 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 11,498 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Current | 326,971 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 390,545 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember
Recorded Total Loans and Leases | 333,331 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialPortfolioSegmentMember | 402,389 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 | 0 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember | 24 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 | 0 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember | 24 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember
Non-Accrual | 3,009 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember | 6,599 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember
Current | 72,255 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember | 96,603 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember
Recorded Total Loans and Leases | 75,264 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_CommercialFinancingReceivableMember | 103,226 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 | 2,666 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember | 3,559 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember
Current | 197,222 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember | 225,455 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember
Recorded Total Loans and Leases | 199,888 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_CommercialRealEstateOtherReceivableMember | 229,014 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 | 5 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember | 320 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember
61 - 90 Days Past Due Accruing | 15 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember | 2 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 | 20 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember | 322 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember
Non-Accrual | 665 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember | 1,340 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember
Current | 57,494 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember | 68,487 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember
Recorded Total Loans and Leases | 58,179 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_SmallBusinessFinancingReceivableMember | 70,149 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 | 739 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 1,768 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
61 - 90 Days Past Due Accruing | 65 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 232 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
Greater Than 90 Days Past Due Accruing | 66 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 80 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
Total Past Due Accruing | 870 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 2,080 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
Non-Accrual | 696 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 712 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
Current | 145,690 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 216,795 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember
Recorded Total Loans and Leases | 147,256 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ConsumerPortfolioSegmentMember | 219,587 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 | 518 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember | 939 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember
61 - 90 Days Past Due Accruing | 5 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember | 113 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember
Greater Than 90 Days Past Due Accruing | 54 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember | 71 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember
Total Past Due Accruing | 577 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember | 1,123 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember
Non-Accrual | 106 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember | 93 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember
Current | 64,540 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember | 123,870 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember
Recorded Total Loans and Leases | 65,223 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_IndirectFinancingReceivableMember | 125,086 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 | 190 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember | 753 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember
61 - 90 Days Past Due Accruing | 60 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember | 63 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember
Greater Than 90 Days Past Due Accruing | 5 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember | 0 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember
Total Past Due Accruing | 255 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember | 816 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember
Non-Accrual | 557 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember | 570 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember
Current | 75,904 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember | 85,690 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember
Recorded Total Loans and Leases | 76,716 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_HomeEquityFinancingReceivablesMember | 87,076 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 | 31 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember | 76 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember
61 - 90 Days Past Due Accruing | 0 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember | 56 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember
Greater Than 90 Days Past Due Accruing | 7 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember | 9 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember
Total Past Due Accruing | 38 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember | 141 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember
Non-Accrual | 33 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember | 49 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember
Current | 5,246 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember | 7,235 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember
Recorded Total Loans and Leases | 5,317 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = nbtb_DirectFinancingReceivableMember | 7,425 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 | 1,162 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 1,725 nbtb_FinancingReceivableRecordedInvestment31To60DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember
61 - 90 Days Past Due Accruing | 265 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 0 nbtb_FinancingReceivableRecordedInvestment61To90DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember
Greater Than 90 Days Past Due Accruing | 671 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 0 nbtb_FinancingReceivableRecordedInvestmentGreaterThan91DaysPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember
Total Past Due Accruing | 2,098 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 1,725 us-gaap_FinancingReceivableRecordedInvestmentPastDue / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember
Non-Accrual | 3,193 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 3,872 us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember
Current | 261,456 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | 302,819 us-gaap_FinancingReceivableRecordedInvestmentCurrent / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember
Recorded Total Loans and Leases | $ 266,747 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember | $ 308,416 us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome / nbtb_ClassOfFinancingReceivablesAxis = nbtb_AcquiredLoansMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = us-gaap_ResidentialPortfolioSegmentMember

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- Definition Financing receivables that are less than 91 days past due but more than 60 days past due. + References No definition available. + Details
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- Definition Financing receivables that are greater than 91 days past due. + References No definition available. + Details
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- Definition The minimum of days past due before a loan is considered nonperforming. + References No definition available. + Details
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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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