Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Securities held for sale, at amortized cost, fair value	$ 28,818	$ 29,600
Common stock, par value	$ 1.25	$ 1.25
Common stock, shares authorized	20,000,000	20,000,000
Common stock, shares issued	7,039,942	7,052,143
Common stock, shares outstanding	7,039,942	7,052,143