CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Loss
Beginning balance at Dec. 31, 2020	$ 261,160	$ 7,753	$ 204,875	$ 99,062	$ (50,515)	$ (15)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	14,097			14,097
Cash dividends	(7,761)			(7,761)
Issuance of common shares pursuant to stock-based compensation plan, net	(835)		(2,881)		2,046
Exercise of SARs	(123)		(415)		292
Stock-based compensation expense	1,519		1,519
Purchase of common shares	(5,260)				(5,260)
Other comprehensive income (loss)	(2,030)					(2,030)
Ending balance at Jun. 30, 2021	260,767	7,753	203,098	105,398	(53,437)	(2,045)
Beginning balance at Mar. 31, 2021	259,487	7,753	202,828	102,247	(49,949)	(3,392)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	7,026			7,026
Cash dividends	(3,875)			(3,875)
Issuance of common shares pursuant to stock-based compensation plan, net	(5)		(455)		450
Exercise of SARs	(7)		(101)		94
Stock-based compensation expense	826		826
Purchase of common shares	(4,032)				(4,032)
Other comprehensive income (loss)	1,347					1,347
Ending balance at Jun. 30, 2021	260,767	7,753	203,098	105,398	(53,437)	(2,045)
Beginning balance at Dec. 31, 2021	245,798	7,753	204,276	112,220	(78,904)	453
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	16,820			16,820
Cash dividends	(7,654)			(7,654)
Issuance of common shares pursuant to stock-based compensation plan, net	(420)		(2,638)		2,218
Exercise of SARs	(85)		(328)		243
Stock-based compensation expense	3,172		3,172
Purchase of common shares	(5,299)				(5,299)
Other comprehensive income (loss)	(46,718)					(46,718)
Ending balance at Jun. 30, 2022	205,614	7,753	204,482	121,386	(81,742)	(46,265)
Beginning balance at Mar. 31, 2022	217,078	7,753	203,149	116,646	(82,348)	(28,122)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	8,562			8,562
Cash dividends	(3,822)			(3,822)
Issuance of common shares pursuant to stock-based compensation plan, net	70		(749)		819
Stock-based compensation expense	2,082		2,082
Purchase of common shares	(213)				(213)
Other comprehensive income (loss)	(18,143)					(18,143)
Ending balance at Jun. 30, 2022	$ 205,614	$ 7,753	$ 204,482	$ 121,386	$ (81,742)	$ (46,265)