Consolidated Statements of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Capital Surplus	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss)
Beginning Balance at Dec. 31, 2020	$ 701,106	$ 47,619	$ 171,304	$ 589,988	$ (139,038)	$ 31,233
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	19,814			19,814
Other comprehensive income (loss)	(15,605)					(15,605)
Cash dividends declared	(9,406)			(9,406)
Stock-based compensation expense	1,153		1,153
Restricted awards granted	0		(464)		464
Exercise of stock options	385		(1,467)		1,852
Purchase of treasury shares	(5,762)				(5,762)
Ending balance at Mar. 31, 2021	691,685	47,619	170,526	600,396	(142,484)	15,628
Beginning Balance at Dec. 31, 2021	681,105	47,619	170,942	641,826	(193,542)	14,260
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	21,342			21,342
Other comprehensive income (loss)	(58,974)					(58,974)
Cash dividends declared	(9,030)			(9,030)
Stock-based compensation expense	971		971
Restricted awards granted	0		(1,707)		1,707
Purchase of treasury shares	(2,984)				(2,984)
Ending balance at Mar. 31, 2022	$ 632,430	$ 47,619	$ 170,206	$ 654,138	$ (194,819)	$ (44,714)