Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
INTEREST AND DIVIDEND INCOME
Interest and fees on loans	$ 51,929	$ 44,087	$ 42,815
Investment income:
Interest and dividends on investment securities	7,555	7,779	7,965
Interest on interest earning deposits with banks and other short-term investments	256	250	192
Total interest and dividend income	59,740	52,116	50,972
INTEREST EXPENSE
Savings, interest bearing checking and money market accounts	1,719	1,433	1,647
Time deposits	1,347	1,312	1,725
Short-term borrowings	126	13	1
Securities sold under agreement to repurchase, short-term	454	497	353
Long-term debt	854	797	799
Total interest expense	4,500	4,052	4,525
Net interest income	55,240	48,064	46,447
Provision for credit losses	1,105	250	150
Net interest income after provision for credit losses	54,135	47,814	46,297
NONINTEREST INCOME
Trust division income	3,709	3,525	3,393
Net debit card income	3,028	3,080	2,660
Overdraft income	2,613	2,004	2,473
Service charges on deposits	1,699	1,504	1,369
Net gains on investment securities			107
Other	1,639	1,847	1,572
Total noninterest income	12,688	11,960	11,574
NONINTEREST EXPENSE
Compensation and benefits	22,976	21,879	20,440
Occupancy expense	4,342	4,251	4,292
Equipment expense	2,734	2,971	2,882
Telephone expense	736	789	895
Legal and professional fees	2,607	1,991	1,924
Mobile & internet banking	1,380	1,597	1,452
Core / Item processing	1,897	1,765	1,876
Marketing	801	561	1,177
State franchise taxes	1,585	1,503	1,435
FDIC insurance	916	886	857
Conversion costs			1,319
Community Bank System, Inc. merger costs	3,019
NUVO Bank & Trust Company acquisition costs	61	1,875
Amortization of core deposit intangible	204	17
Other	3,993	3,886	3,665
Total noninterest expense	47,251	43,971	42,214
Income before provision for income taxes	19,572	15,803	15,657
Provision for income taxes	4,689	3,185	3,532
NET INCOME	$ 14,883	$ 12,618	$ 12,125
Basic earnings per common share (in dollars per share)	$ 2.17	$ 1.98	$ 1.92
Diluted earnings per common share (in dollars per share)	$ 2.16	$ 1.98	$ 1.91