Subsequent Events

9 Months Ended

Sep. 30, 2012

Subsequent Events [Abstract]

Subsequent Events [Text Block]

Note 4. Subsequent Event

On October 7, 2012, the Company and Alliance Financial Corporation ("Alliance") entered into a definitive agreement and plan of merger pursuant to which Alliance will merge with and into NBT Bancorp, with NBT Bancorp continuing as the surviving corporation. The agreement also provides for Alliance Bank, N.A., a wholly-owned subsidiary of Alliance, to be merged with and into the Bank following completion of the merger. Alliance, with assets of approximately $1.4 billion at June 30, 2012, is headquartered in Syracuse, N.Y. Its primary subsidiary, Alliance Bank, N.A., is a nationally-chartered community bank with 28 banking locations in central New York. The transaction is valued at approximately $233.4 million, to be paid in the form of shares of the Company's common stock. Subject to the required approvals of NBT Bancorp and Alliance shareholders, requisite regulatory approvals and other customary closing conditions, the merger is expected to be completed in the early 2013.