CONSOLIDATED STATEMENTS OF CONDITION (UNAUDITED) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Statement of Financial Position [Abstract]
Securities held to maturity, fair value	$ 25,871	$ 26,911	$ 40,758
Allowance for loan losses	$ 14,020	$ 13,964	$ 13,417
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	7,112,282	7,108,620	7,097,140
Common stock, shares outstanding	7,049,682	7,046,020	7,034,540
Treasury stock, shares	62,600	62,600	62,600