XML 32 R21.htm IDEA: XBRL DOCUMENT
v3.19.1

Description of Business (Policies) | 3 Months Ended
--- | ---
Mar. 31, 2019
Description of Business [Abstract] |
Nature of Operations | NBT Bancorp Inc. (the “Registrant” or the “Company”) is a registered financial holding company incorporated in the state of Delaware in 1986, with its principal headquarters located in Norwich, New York. The principal assets of the Registrant consist of all of the outstanding shares of common stock of its subsidiaries, including: NBT Bank, National Association (the “Bank”), NBT Financial Services, Inc. (“NBT Financial”), NBT Holdings, Inc. (“NBT Holdings”), CNBF Capital Trust I, NBT Statutory Trust I, NBT Statutory Trust II, Alliance Financial Capital Trust I and Alliance Financial Capital Trust II (collectively, the “Trusts”). The Company’s principal sources of revenue are the management fees and dividends it receives from the Bank, NBT Financial and NBT Holdings. The Company’s business, primarily conducted through the Bank, consists of providing commercial banking, retail banking and wealth management services primarily to customers in its market area, which includes central and upstate New York, northeastern Pennsylvania, southern New Hampshire, western Massachusetts, Vermont and the southern coastal Maine area. The Company has been, and intends to continue to be, a community-oriented financial institution offering a variety of financial services. The Company’s business philosophy is to operate as a community bank with local decision-making, providing a broad array of banking and financial services to retail, commercial and municipal customers.

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

X
- Definition Disclosure of nature of operations and accounting policy for basis of accounting, or basis of presentation, used to prepare the financial statements. + References No definition available. + Details
Name: | nbtb_NatureOfOperationsPolicyTextBlock
Namespace Prefix: | nbtb_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration