Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Statement Of Financial Position [Abstract]
Held-to-maturity, fair value	$ 232,675	$ 174,528
Common stock, par value	$ 6.25	$ 6.25
Common stock, authorized shares	9,000,000	9,000,000
Common stock, shares issued	2,980,602	2,980,602
Common stock, shares outstanding	2,718,024	2,718,024
Treasury stock, at cost	262,578	262,578