CONSOLIDATED STATEMENTS OF CONDITION (UNAUDITED) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Statement of Financial Position [Abstract]
Securities held to maturity, fair value	$ 47,373	$ 55,425	$ 58,566
Allowance for loan losses	$ 14,105	$ 14,194	$ 14,488
Preferred stock, par value (in dollars per share)	$ 2.50	$ 2.50	$ 2.50
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)	$ 2.50	$ 2.50	$ 2.50
Common stock, shares authorized	20,000,000	20,000,000	20,000,000
Common stock, shares issued	7,082,245	6,126,738	6,123,662
Common stock, shares outstanding	7,019,645	6,064,138	6,061,062
Treasury stock, shares	62,600	62,600	62,600