XML 60 R50.htm IDEA: XBRL DOCUMENT
v3.23.1

Allowance for Credit Losses and Credit Quality of Loans, Financial Effect of Modifications Made to Borrowers Experiencing Financial Difficulty (Details) $ in Thousands | 3 Months Ended
--- | ---
Mar. 31, 2023 USD ($)
ASU 2022-02 [Member] |
Financing Receivable Financial Effect of Modifications Made to Borrowers Experiencing Financial Difficulty [Abstract] |
Financing receivables with payment default that were modified to borrowers experiencing financial difficulty | $ 0
Residential [Member] | Term Extension [Member] |
Financing Receivable Financial Effect of Modifications Made to Borrowers Experiencing Financial Difficulty [Abstract] |
Period of increase in weighted-average maturity | 18 years

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

X
- Definition Amortized cost of financing receivable with payment default in current period and modified within previous 12 months preceding payment default for debtor experiencing financial difficulty. + References No definition available. + Details
Name: | nbtb_FinancingReceivableModifiedSubsequentDefault
Namespace Prefix: | nbtb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Period of increase in weighted average maturity of financing receivable modified for debtor experiencing financial difficulty, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | nbtb_FinancingReceivableModifiedWeightedAverageTermIncreaseFromModification
Namespace Prefix: | nbtb_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=nbtb_AccountingStandardsUpdate202202Member
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: |

X
- Details
Name: | us-gaap_LoanRestructuringModificationAxis=us-gaap_ExtendedMaturityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |