Consolidated Condensed Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Net sales	$ 104,881	$ 105,041
Cost of sales	64,424	68,293
Gross margin	40,457	36,748
Selling, engineering and administration	26,130	26,774
Operating earnings	14,327	9,974
Interest expense, net	129	290
Other pension and postretirement costs (benefits)	47	(19)
Earnings before income taxes	14,151	9,703
Provision for income taxes	3,327	2,157
Net earnings	$ 10,824	$ 7,546
Earnings per share:
Basic	$ 0.37	$ 0.26
Diluted	0.37	0.26
Dividends declared per common share	$ 0.15	$ 0.13
Shares used in computation of earnings per share:
Basic	29,028,964	28,932,787
Impact of dilutive securities	209,660	217,259
Diluted	29,238,624	29,150,046