Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock at $1 par value	[1]	Capital in excess of par value	Reinvested earnings	Accumulated other comprehensive income (loss)	Employee benefit stock	Treasury stock
Balance at beginning of period at Dec. 31, 2018	$ 303,503	$ 37,198		$ 38,082	$ 257,313	$ 580	$ (306)	$ (29,364)
Net earnings	47,177				47,177
Pension and postretirement benefits (net of tax effect)	(97)					(97)
Foreign currency translation	(58)					(58)
Cash dividends	(18,611)				(18,611)
Stock options exercised	1,961	2		1,708				251
ESSOP transactions	553			401			152
Stock-based compensation	1,214			1,214
Purchase of common stock for treasury stock	(5,207)							(5,207)
Issuance of treasury stock	633			551				82
Balance at end of period at Dec. 31, 2019	331,068	37,200		41,956	285,879	425	(154)	(34,238)
Net earnings	49,343				49,343
Pension and postretirement benefits (net of tax effect)	(208)					(208)
Foreign currency translation	1,096					1,096
Cash dividends	(20,372)				(20,372)
Stock options exercised	1,058	21		877				160
ESSOP transactions	434			280			$ 154
Stock-based compensation	1,415			1,415
Purchase of common stock for treasury stock	(3,116)							(3,116)
Issuance of treasury stock	541			436				105
Balance at end of period at Dec. 31, 2020	361,259	37,221		44,964	314,850	1,313		(37,089)
Net earnings	60,884				60,884
Pension and postretirement benefits (net of tax effect)	339					339
Foreign currency translation	(1,516)					(1,516)
Cash dividends	(22,199)				(22,199)
Stock options exercised	2,036			1,622				414
Stock-based compensation	2,330			2,330
Purchase of common stock for treasury stock	(460)							(460)
Issuance of treasury stock	397			308				89
Balance at end of period at Dec. 31, 2021	$ 403,070	$ 37,221		$ 49,224	$ 353,535	$ 136		$ (37,046)

[1] Each common share of stock equals $1 par value; therefore, the number of common shares is the same as the dollar value.