Acquisition (Tables) (Alliance Financial Corporation [Member])

3 Months Ended

Mar. 31, 2013

Alliance Financial Corporation [Member]

Business Acquisition [Line Items]

Consideration paid, assets acquired, and liabilities assumed

In connection with the merger, the consideration paid and the fair value of the assets acquired and the liabilities assumed on the date of acquisition are as summarized in the following table, in thousands:

Consideration paid:
NBT Bancorp common stock issued to Alliance common shareholders	$	225,551
Cash in lieu of fractional shares paid to Alliance common shareholders		11
Less treasury shares		5,779
Total consideration paid	$	219,783
Recognized Amounts of Identifiable Assets Acquired and (Liabilities Assumed), At Fair Value:
Cash and short term investments	$	81,060
Securities		320,618
Loans and Leases		904,473
Intangible assets		13,161
Other assets		71,900
Deposits		(1,113,420	)
Borrowings		(126,530	)
Trust preferred debentures		(25,774	)
Other liabilities		(17,952	)
Total identifiable net assets	$	107,536
Goodwill	$	112,247

Acquired loan portfolio

Information about the acquired loan portfolio as of March 8, 2013 is as follows (in thousands):

Contractually required principal and interest at acquisition	$	908,614
Contractual cash flows not expected to be collected		(15,466	)
Expected cash flows at acquisition		893,148
Interest component of expected cash flows (accretable premium)		11,325
Fair value of acquired loans	$	904,473

Schedule of unaudited pro forma amounts related acquisition

The following table presents unaudited pro forma information as if the acquisition had occurred on January 1, 2012 under the "Pro forma" columns.  This pro forma information gives the effect to certain adjustments, including purchase accounting fair value adjustments, amortization of core deposit and other intangibles and related income tax effects.  Merger and acquisition integration costs related to the Alliance acquisitions are excluded from the periods in which they were incurred.  The pro forma information does not necessarily reflect the results of operations that would have occurred had the Company merged with Alliance at the beginning of 2012.  Cost savings are also not reflected in the unaudited pro forma amounts for the three months ended March 31, 2012 and 2013.

	Pro forma
	Three months ended March 31,
	2013		2012
Net interest income	$	59,052	$	59,544
Noninterest income		29,908		27,532
Net income		16,509		16,158