XML 60 R53.htm IDEA: XBRL DOCUMENT
v3.20.1

Allowance for Credit Losses and Credit Quality of Loans, Average Recorded Investments on Loans Specifically Evaluated for Impairment and Interest Income Recognized (Details) $ in Thousands | 3 Months Ended
--- | ---
Mar. 31, 2019 USD ($)
Average Recorded Investment and Interest Income Recognized [Abstract] |
Average recorded investment | $ 21,062
Interest income recognized | 214
Originated Loans [Member] |
Average Recorded Investment and Interest Income Recognized [Abstract] |
Average recorded investment | 21,062
Interest income recognized | 214
Originated Loans [Member] | Commercial Loans [Member] |
Average Recorded Investment and Interest Income Recognized [Abstract] |
Average recorded investment | 6,007
Interest income recognized | 37
Originated Loans [Member] | Commercial Loans [Member] | C&I [Member] |
Average Recorded Investment and Interest Income Recognized [Abstract] |
Average recorded investment | 462
Interest income recognized | 1
Originated Loans [Member] | Commercial Loans [Member] | CRE [Member] |
Average Recorded Investment and Interest Income Recognized [Abstract] |
Average recorded investment | 4,282
Interest income recognized | 30
Originated Loans [Member] | Commercial Loans [Member] | Business Banking [Member] |
Average Recorded Investment and Interest Income Recognized [Abstract] |
Average recorded investment | 1,263
Interest income recognized | 6
Originated Loans [Member] | Consumer Loans [Member] |
Average Recorded Investment and Interest Income Recognized [Abstract] |
Average recorded investment | 7,889
Interest income recognized | 100
Originated Loans [Member] | Consumer Loans [Member] | Indirect Auto [Member] |
Average Recorded Investment and Interest Income Recognized [Abstract] |
Average recorded investment | 173
Interest income recognized | 2
Originated Loans [Member] | Consumer Loans [Member] | Direct [Member] |
Average Recorded Investment and Interest Income Recognized [Abstract] |
Average recorded investment | 7,716
Interest income recognized | 98
Originated Loans [Member] | Residential Real Estate [Member] |
Average Recorded Investment and Interest Income Recognized [Abstract] |
Average recorded investment | 7,166
Interest income recognized | $ 77

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

X
- Definition Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5212-111524 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5258-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=nbtb_OriginatedLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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

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

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

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

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

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