Consolidated Condensed 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 (at cost)
Balance at beginning of period at Dec. 31, 2019	$ 331,068	$ 37,200		$ 41,956	$ 285,879	$ 425	$ (154)	$ (34,238)
Net earnings	11,854				11,854
Pension and postretirement benefits (net of tax effect)	1					1
Foreign currency translation	(627)					(627)
Cash dividends	(4,948)				(4,948)
Stock options exercised	478	20		438				20
Stock-based compensation	307			307
Purchase of common stock for treasury stock	(2,467)							(2,467)
Issuance of treasury stock	55			(11)				66
Balance at end of period at Mar. 31, 2020	335,721	37,220		42,690	292,785	(201)	$ (154)	(36,619)
Balance at beginning of period at Dec. 31, 2020	361,259	37,221		44,964	314,850	1,313		(37,089)
Net earnings	13,781				13,781
Pension and postretirement benefits (net of tax effect)	3					3
Foreign currency translation	(714)					(714)
Cash dividends	(5,248)				(5,248)
Stock options exercised	352			281				71
Stock-based compensation	374			374
Issuance of treasury stock	42			(20)				62
Balance at end of period at Mar. 31, 2021	$ 369,849	$ 37,221		$ 45,599	$ 323,383	$ 602		$ (36,956)

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