XML 30 R35.htm IDEA: XBRL DOCUMENT v2.4.1.9
Allowance for Loan Losses and Credit Quality of Loans, Credit Quality by Loan Class (Details) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Originated Loans [Member] | Commercial Credit Exposure [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Financing Receivable $ 1,760,672us-gaap_NotesReceivableNet
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialPortfolioSegmentMember
/ nbtb_ClassOfFinancingReceivablesAxis
= nbtb_OriginatedLoansMember		 $ 1,741,936us-gaap_NotesReceivableNet
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= us-gaap_CommercialPortfolioSegmentMember
/ nbtb_ClassOfFinancingReceivablesAxis
= nbtb_OriginatedLoansMember
Originated Loans [Member] | Commercial Credit Exposure [Member] | Pass [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Financing Receivable 1,674,082us-gaap_NotesReceivableNet
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialPortfolioSegmentMember
/ nbtb_ClassOfFinancingReceivablesAxis
= nbtb_OriginatedLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember		 1,648,664us-gaap_NotesReceivableNet
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= us-gaap_CommercialPortfolioSegmentMember
/ nbtb_ClassOfFinancingReceivablesAxis
= nbtb_OriginatedLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
Originated Loans [Member] | Commercial Credit Exposure [Member] | Special Mention [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Financing Receivable 35,812us-gaap_NotesReceivableNet
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialPortfolioSegmentMember
/ nbtb_ClassOfFinancingReceivablesAxis
= nbtb_OriginatedLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember		 23,680us-gaap_NotesReceivableNet
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= us-gaap_CommercialPortfolioSegmentMember
/ nbtb_ClassOfFinancingReceivablesAxis
= nbtb_OriginatedLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
Originated Loans [Member] | Commercial Credit Exposure [Member] | Substandard [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Financing Receivable 50,770us-gaap_NotesReceivableNet
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialPortfolioSegmentMember
/ nbtb_ClassOfFinancingReceivablesAxis
= nbtb_OriginatedLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember		 69,584us-gaap_NotesReceivableNet
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= us-gaap_CommercialPortfolioSegmentMember
/ nbtb_ClassOfFinancingReceivablesAxis
= nbtb_OriginatedLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
Originated Loans [Member] | Commercial Credit Exposure [Member] | Doubtful [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Financing Receivable 8us-gaap_NotesReceivableNet
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialPortfolioSegmentMember
/ nbtb_ClassOfFinancingReceivablesAxis
= nbtb_OriginatedLoansMember
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= us-gaap_DoubtfulMember		 8us-gaap_NotesReceivableNet
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= us-gaap_CommercialPortfolioSegmentMember
/ nbtb_ClassOfFinancingReceivablesAxis
= nbtb_OriginatedLoansMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
Originated Loans [Member] | Commercial Credit Exposure [Member] | Commercial [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Financing Receivable 621,513us-gaap_NotesReceivableNet
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialPortfolioSegmentMember
/ nbtb_ClassOfFinancingReceivablesAxis
= nbtb_OriginatedLoansMember
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= nbtb_CommercialFinancingReceivableMember		 615,147us-gaap_NotesReceivableNet
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= us-gaap_CommercialPortfolioSegmentMember
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= nbtb_OriginatedLoansMember
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= nbtb_CommercialFinancingReceivableMember
Originated Loans [Member] | Commercial Credit Exposure [Member] | Commercial [Member] | Pass [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Financing Receivable 584,916us-gaap_NotesReceivableNet
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= us-gaap_CommercialPortfolioSegmentMember
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= nbtb_CommercialFinancingReceivableMember
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= us-gaap_PassMember		 570,884us-gaap_NotesReceivableNet
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= us-gaap_CommercialPortfolioSegmentMember
/ nbtb_ClassOfFinancingReceivablesAxis
= nbtb_OriginatedLoansMember
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= nbtb_CommercialFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
Originated Loans [Member] | Commercial Credit Exposure [Member] | Commercial [Member] | Special Mention [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Financing Receivable 15,872us-gaap_NotesReceivableNet
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= us-gaap_CommercialPortfolioSegmentMember
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= nbtb_CommercialFinancingReceivableMember
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= us-gaap_SpecialMentionMember		 6,022us-gaap_NotesReceivableNet
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= us-gaap_CommercialPortfolioSegmentMember
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/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
Originated Loans [Member] | Commercial Credit Exposure [Member] | Commercial [Member] | Substandard [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Financing Receivable 20,725us-gaap_NotesReceivableNet
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= nbtb_CommercialFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
Originated Loans [Member] | Commercial Credit Exposure [Member] | Commercial [Member] | Doubtful [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Financing Receivable 0us-gaap_NotesReceivableNet
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= nbtb_CommercialFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
Originated Loans [Member] | Commercial Credit Exposure [Member] | Commercial Real Estate [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Financing Receivable 1,082,619us-gaap_NotesReceivableNet
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= us-gaap_CommercialPortfolioSegmentMember
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= us-gaap_CommercialRealEstateOtherReceivableMember		 1,068,868us-gaap_NotesReceivableNet
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Originated Loans [Member] | Commercial Credit Exposure [Member] | Commercial Real Estate [Member] | Pass [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Financing Receivable 1,036,469us-gaap_NotesReceivableNet
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= us-gaap_CommercialRealEstateOtherReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
Originated Loans [Member] | Commercial Credit Exposure [Member] | Commercial Real Estate [Member] | Special Mention [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Financing Receivable 19,820us-gaap_NotesReceivableNet
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= us-gaap_CommercialPortfolioSegmentMember
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= us-gaap_SpecialMentionMember
Originated Loans [Member] | Commercial Credit Exposure [Member] | Commercial Real Estate [Member] | Substandard [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Financing Receivable 26,330us-gaap_NotesReceivableNet
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Originated Loans [Member] | Commercial Credit Exposure [Member] | Commercial Real Estate [Member] | Doubtful [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Financing Receivable 0us-gaap_NotesReceivableNet
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Originated Loans [Member] | Commercial Credit Exposure [Member] | Agricultural [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Financing Receivable 32,009us-gaap_NotesReceivableNet
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Originated Loans [Member] | Commercial Credit Exposure [Member] | Agricultural [Member] | Pass [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Financing Receivable 29,781us-gaap_NotesReceivableNet
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Originated Loans [Member] | Commercial Credit Exposure [Member] | Agricultural [Member] | Special Mention [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Financing Receivable 117us-gaap_NotesReceivableNet
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Originated Loans [Member] | Commercial Credit Exposure [Member] | Agricultural [Member] | Substandard [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Financing Receivable 2,103us-gaap_NotesReceivableNet
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Originated Loans [Member] | Commercial Credit Exposure [Member] | Agricultural [Member] | Doubtful [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Financing Receivable 8us-gaap_NotesReceivableNet
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Originated Loans [Member] | Commercial Credit Exposure [Member] | Agricultural Real Estate [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Financing Receivable 24,531us-gaap_NotesReceivableNet
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Originated Loans [Member] | Commercial Credit Exposure [Member] | Agricultural Real Estate [Member] | Pass [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Financing Receivable 22,916us-gaap_NotesReceivableNet
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Originated Loans [Member] | Commercial Credit Exposure [Member] | Agricultural Real Estate [Member] | Special Mention [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Financing Receivable 3us-gaap_NotesReceivableNet
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Originated Loans [Member] | Commercial Credit Exposure [Member] | Agricultural Real Estate [Member] | Substandard [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Financing Receivable 1,612us-gaap_NotesReceivableNet
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Originated Loans [Member] | Commercial Credit Exposure [Member] | Agricultural Real Estate [Member] | Doubtful [Member]    
Financing Receivable, Recorded Investment [Line Items]    
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Originated Loans [Member] | Business Banking Credit Exposure [Member]    
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Originated Loans [Member] | Residential Mortgage Credit Exposure [Member] | Residential Mortgage [Member] | Nonperforming [Member]    
Financing Receivable, Recorded Investment [Line Items]    
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Acquired Loans [Member] | Commercial Credit Exposure [Member] | Substandard [Member]    
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Financing Receivable, Recorded Investment [Line Items]    
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Acquired Loans [Member] | Consumer Credit Exposure [Member] | Direct [Member] | Nonperforming [Member]    
Financing Receivable, Recorded Investment [Line Items]    
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Acquired Loans [Member] | Residential Mortgage Credit Exposure [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Financing Receivable 260,857us-gaap_NotesReceivableNet
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Acquired Loans [Member] | Residential Mortgage Credit Exposure [Member] | Performing [Member]    
Financing Receivable, Recorded Investment [Line Items]    
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Acquired Loans [Member] | Residential Mortgage Credit Exposure [Member] | Nonperforming [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Financing Receivable 3,101us-gaap_NotesReceivableNet
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Acquired Loans [Member] | Residential Mortgage Credit Exposure [Member] | Residential Mortgage [Member]    
Financing Receivable, Recorded Investment [Line Items]    
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Acquired Loans [Member] | Residential Mortgage Credit Exposure [Member] | Residential Mortgage [Member] | Performing [Member]    
Financing Receivable, Recorded Investment [Line Items]    
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Acquired Loans [Member] | Residential Mortgage Credit Exposure [Member] | Residential Mortgage [Member] | Nonperforming [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Financing Receivable $ 3,101us-gaap_NotesReceivableNet
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