XML 81 R66.htm IDEA: XBRL DOCUMENT v3.25.0.1

Summary of Significant Accounting Policies, Other Financial Instruments (Details)	12 Months Ended
	Dec. 31, 2024
Other Financial Instruments [Abstract]
Standby letters of credit expiration period	1 year

X

- References

No definition available.

+ Details

Name:	nbtb_OtherFinancialInstrumentsAbstract
Namespace Prefix:	nbtb_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Represents expiration period of standby letters of credit, 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_StandbyLettersOfCreditExpirationPeriod
Namespace Prefix:	nbtb_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration