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v2.4.1.9

Junior Subordinated Debt (Details) (USD $) | 12 Months Ended
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Dec. 31, 2014
Debt Instrument [Line Items] |
Number of statutory business trusts included in the Trusts | 5 nbtb_NumberOfStatutoryBusinessTrustsIncludedInTrusts
Minimum assets for bank holding companies to be subject to the same capital requirements as insured depository institutions | $ 500,000,000 nbtb_MinimumAssetsForBankHoldingCompaniesToBeSubjectToSameCapitalRequirementsAsInsuredDepositoryInstitutions
CNBF Capital Trust I Debenture [Member] |
Debt Instrument [Line Items] |
Issuance Date | Aug. 01, 1999
Trust Preferred Securities Outstanding | 18,000,000 us-gaap_DebtInstrumentFaceAmount / us-gaap_DebtInstrumentAxis = nbtb_CnbfCapitalTrustIDebentureMember
Interest Rate | 3-month LIBOR plus 2.75%
Trust Preferred Debt Owed To Trust | 18,720,000 nbtb_DebtInstrumentAmountOwedToTrust / us-gaap_DebtInstrumentAxis = nbtb_CnbfCapitalTrustIDebentureMember
Final Maturity Date | Aug. 01, 2029
Number of wholly owned Delaware statutory business trusts | 1
NBT Statutory Trust I Debenture [Member] |
Debt Instrument [Line Items] |
Issuance Date | Nov. 01, 2005
Trust Preferred Securities Outstanding | 5,000,000 us-gaap_DebtInstrumentFaceAmount / us-gaap_DebtInstrumentAxis = nbtb_NbtStatutoryTrustIDebentureMember
Interest Rate | 3-month LIBOR plus 1.40%
Trust Preferred Debt Owed To Trust | 5,155,000 nbtb_DebtInstrumentAmountOwedToTrust / us-gaap_DebtInstrumentAxis = nbtb_NbtStatutoryTrustIDebentureMember
Final Maturity Date | Dec. 01, 2035
NBT Statutory Trust II Debenture [Member] |
Debt Instrument [Line Items] |
Issuance Date | Feb. 01, 2006
Trust Preferred Securities Outstanding | 50,000,000 us-gaap_DebtInstrumentFaceAmount / us-gaap_DebtInstrumentAxis = nbtb_NbtStatutoryTrustIiDebentureMember
Interest Rate | 3-month LIBOR plus 1.40%
Trust Preferred Debt Owed To Trust | 51,547,000 nbtb_DebtInstrumentAmountOwedToTrust / us-gaap_DebtInstrumentAxis = nbtb_NbtStatutoryTrustIiDebentureMember
Final Maturity Date | Mar. 01, 2036
Alliance Financial Capital Trust I [Member] |
Debt Instrument [Line Items] |
Issuance Date | Dec. 01, 2003
Trust Preferred Securities Outstanding | 10,000,000 us-gaap_DebtInstrumentFaceAmount / us-gaap_DebtInstrumentAxis = nbtb_AllianceFinancialCapitalTrustIMember
Interest Rate | 3-month LIBOR plus 2.85%
Trust Preferred Debt Owed To Trust | 10,310,000 nbtb_DebtInstrumentAmountOwedToTrust / us-gaap_DebtInstrumentAxis = nbtb_AllianceFinancialCapitalTrustIMember
Final Maturity Date | Jan. 01, 2034
Alliance Financial Capital Trust II [Member] |
Debt Instrument [Line Items] |
Issuance Date | Sep. 01, 2006
Trust Preferred Securities Outstanding | 15,000,000 us-gaap_DebtInstrumentFaceAmount / us-gaap_DebtInstrumentAxis = nbtb_AllianceFinancialCapitalTrustIiMember
Interest Rate | 3-month LIBOR plus 1.65%
Trust Preferred Debt Owed To Trust | 15,464,000 nbtb_DebtInstrumentAmountOwedToTrust / us-gaap_DebtInstrumentAxis = nbtb_AllianceFinancialCapitalTrustIiMember
Final Maturity Date | Sep. 01, 2036
NBT Bancorp Inc [Member] |
Debt Instrument [Line Items] |
Trust equity method investment | 1,000,000 us-gaap_EquityMethodInvestments / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Alliance Financial Capital [Member] |
Debt Instrument [Line Items] |
Number of wholly owned Delaware statutory business trusts | 2
Trusts [Member] |
Debt Instrument [Line Items] |
Trust Preferred Securities Outstanding | 98,000,000 us-gaap_DebtInstrumentFaceAmount / dei_LegalEntityAxis = nbtb_CombinedTrustsMember
Trust Preferred Debt Owed To Trust | 101,000,000 nbtb_DebtInstrumentAmountOwedToTrust / dei_LegalEntityAxis = nbtb_CombinedTrustsMember
Trust equity method investment | 3,200,000 us-gaap_EquityMethodInvestments / dei_LegalEntityAxis = nbtb_CombinedTrustsMember
Debentures period semi-annual deferral periods | 10 nbtb_DistributionDeferralPeriodSubordinatedDebentures / dei_LegalEntityAxis = nbtb_CombinedTrustsMember
Trust preferred securities included in Tier I capital | $ 97,000,000 nbtb_TrustPreferredSecuritiesIncludedTierOneCapital / dei_LegalEntityAxis = nbtb_CombinedTrustsMember

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- Definition For an issue of Subordinated Debentures, maximum distribution deferral period (payments of interest). + References No definition available. + Details
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- Definition The minimum assets for bank holding companies to be subject to the same capital requirements as insured depository institutions under the Dodd-Frank Act. + References No definition available. + Details
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- Definition Description of the interest rate as being fixed or variable, and, if variable, identification of the index or rate on which the interest rate is based and the number of points or percentage added to that index or rate to set the rate, and other pertinent information, such as frequency of rate resets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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