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, 2017	$ 277,451	$ 37,165		$ 32,182	$ 244,224	$ (10,893)	$ (461)	$ (24,766)
Increase (Decrease) in Stockholders' Equity
Net earnings	13,700				13,700
ASU adoption impact | Accounting Standards Update 2014-09	(128)				(128)
Pension and postretirement benefits (net of tax effect)	5,772					5,772
Foreign currency translation	(387)					(387)
Cash dividends	(7,554)				(7,554)
Stock options exercised	231	12		219
Stock-based compensation	944			944
Purchase of common stock for treasury stock	(1,989)							(1,989)
Issuance of treasury stock	430			336				94
Balance at end of period at Jun. 30, 2018	288,470	37,177		33,681	250,242	(5,508)	(461)	(26,661)
Balance at beginning of period at Mar. 31, 2018	280,722	37,177		32,871	247,865	(10,411)	(461)	(26,319)
Increase (Decrease) in Stockholders' Equity
Net earnings	6,154				6,154
Pension and postretirement benefits (net of tax effect)	5,711					5,711
Foreign currency translation	(808)					(808)
Cash dividends	(3,777)				(3,777)
Stock-based compensation	473			473
Purchase of common stock for treasury stock	(370)							(370)
Issuance of treasury stock	365			337				28
Balance at end of period at Jun. 30, 2018	288,470	37,177		33,681	250,242	(5,508)	(461)	(26,661)
Balance at beginning of period at Dec. 31, 2018	303,503	37,198		38,082	257,313	580	(306)	(29,364)
Increase (Decrease) in Stockholders' Equity
Net earnings	22,182				22,182
Pension and postretirement benefits (net of tax effect)	349					349
Foreign currency translation	137					137
Cash dividends	(8,723)				(8,723)
Stock options exercised	748	2		640				106
Stock-based compensation	554			554
Purchase of common stock for treasury stock	(2,837)							(2,837)
Issuance of treasury stock	539			470				69
Balance at end of period at Jun. 30, 2019	316,452	37,200		39,746	270,772	1,066	(306)	(32,026)
Balance at beginning of period at Mar. 31, 2019	308,613	37,200		38,756	263,777	311	(306)	(31,125)
Increase (Decrease) in Stockholders' Equity
Net earnings	11,358				11,358
Pension and postretirement benefits (net of tax effect)	360					360
Foreign currency translation	395					395
Cash dividends	(4,363)				(4,363)
Stock options exercised	277			243				34
Stock-based compensation	289			289
Purchase of common stock for treasury stock	(964)							(964)
Issuance of treasury stock	487			458				29
Balance at end of period at Jun. 30, 2019	$ 316,452	$ 37,200		$ 39,746	$ 270,772	$ 1,066	$ (306)	$ (32,026)

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