Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Loans, allowance for loan losses	$ 7,902	$ 7,770
Common stock, par value	$ 5	$ 5
Common stock, authorized shares	30,000,000	30,000,000
Common stock, outstanding shares	13,201,682	13,203,605
Preferred stock, outstanding shares	0	0