CONSOLIDATED STATEMENTS OF CONDITION (UNAUDITED) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Statement of Financial Position [Abstract]
Securities held to maturity, fair value	$ 70,569	$ 71,363	$ 71,746
Allowance for loan losses	$ 14,540	$ 14,747	$ 15,065
Preferred stock, par value (in dollars per share)	$ 2.5	$ 2.5	$ 2.5
Preferred stock, shares authorized	20,000,000	20,000,000	20,000,000
Preferred stock, shares outstanding	0	0	0
Common stock, par value (in dollars per share)	$ 2.5	$ 2.5	$ 2.5
Common stock, shares authorized	20,000,000	20,000,000	20,000,000
Common stock, shares issued	6,107,053	6,102,324	6,082,775
Common stock, shares outstanding	6,044,453	6,039,724	6,020,175
Treasury stock, shares	62,600	62,600	62,600