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	7,546				7,546
ASU adoption impact | Accounting Standards Update 2014-09	(128)				(128)
Pension and postretirement benefits (net of tax effect)	61					61
Foreign currency translation	421					421
Cash dividends	(3,777)				(3,777)
Stock options exercised	231	12		219
Stock-based compensation	471			471
Purchase of common stock for treasury stock	(1,619)							(1,619)
Issuance of treasury stock	65			(1)				66
Balance at end of period at Mar. 31, 2018	280,722	37,177		32,871	247,865	(10,411)	(461)	(26,319)
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	10,824				10,824
Pension and postretirement benefits (net of tax effect)	(12)					(12)
Foreign currency translation	(257)					(257)
Cash dividends	(4,360)				(4,360)
Stock options exercised	471	2		397				72
Stock-based compensation	265			265
Purchase of common stock for treasury stock	(1,873)							(1,873)
Issuance of treasury stock	52			12				40
Balance at end of period at Mar. 31, 2019	$ 308,613	$ 37,200		$ 38,756	$ 263,777	$ 311	$ (306)	$ (31,125)

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