XML 71 R60.htm IDEA: XBRL DOCUMENT
v3.25.1

Allowance for Credit Losses and Credit Quality of Loans, Financial Effect of Modifications Made to Borrowers Experiencing Financial Difficulty (Details) | 3 Months Ended
--- | ---
Mar. 31, 2025 | Mar. 31, 2024
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 | 5 years 2 months 12 days | 7 years 4 months 24 days

X
- References No definition available. + Details
Name: | nbtb_FinancingReceivableFinancialEffectOfModificationsMadeToBorrowersExperiencingFinancialDifficultyAbstract
Namespace Prefix: | nbtb_
Data Type: | xbrli:stringItemType
Balance Type: | na
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 Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 12A -Publisher FASB -URI https://asc.fasb.org/1943274/2147481933/310-10-55-12A + Details
Name: | us-gaap_FinancingReceivableModifiedWeightedAverageTermIncreaseFromModification
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

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: |