Consolidated Statement of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Restricted Shares	Common Shares	Common Shares Restricted Shares	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock	Treasury Stock Restricted Shares
Beginning balance at Dec. 31, 2020	$ 575,673		$ 422,536		$ 190,691	$ 1,336	$ (38,890)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	15,463				15,463
Other comprehensive loss, net of tax	(6,298)					(6,298)
Cash dividends declared	(6,833)				(6,833)
Reissuance of treasury stock for common share awards		$ 0		$ (1,740)				$ 1,740
Reissuance of treasury stock for deferred compensation plan for Boards of Directors	2						2
Repurchase of treasury stock in connection with employee incentive program and compensation plan for Boards of Directors	(911)						(911)
Common shares issued under dividend reinvestment plan	288		288
Common shares issued under compensation plan for Boards of Directors	194		53				141
Common shares issued under employee stock purchase plan	117		35				82
Stock-based compensation	1,198		1,198
Ending balance at Mar. 31, 2021	578,893		422,370		199,321	(4,962)	(37,836)
Beginning balance at Dec. 31, 2021	845,025		686,282		207,076	(11,619)	(36,714)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	23,577				23,577
Other comprehensive loss, net of tax	(51,048)					(51,048)
Cash dividends declared	(10,176)				(10,176)
Reissuance of treasury stock for common share awards		$ 0		$ (3,998)				$ 3,998
Repurchase of treasury stock in connection with employee incentive program and compensation plan for Boards of Directors	(1,230)						(1,230)
Common shares issued under dividend reinvestment plan	305		305
Common shares issued under compensation plan for Boards of Directors	124		31				93
Common shares issued under employee stock purchase plan	186		46				140
Stock-based compensation	1,577		1,577
Ending balance at Mar. 31, 2022	$ 808,340		$ 684,243		$ 220,477	$ (62,667)	$ (33,713)