Consolidated Condensed Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Net sales	$ 113,587	$ 108,646	$ 313,214	$ 317,069
Cost of sales	68,564	66,976	189,019	194,666
Gross margin	45,023	41,670	124,195	122,403
Selling, engineering and administration	25,509	25,225	76,001	76,598
Operating earnings	19,514	16,445	48,194	45,805
Interest (income) expense, net	(46)	66	18	280
Other pension and postretirement costs	21	41	109	123
Earnings before income taxes	19,539	16,338	48,067	45,402
Provision for income taxes	4,678	3,617	11,818	10,499
Net earnings	$ 14,861	$ 12,721	$ 36,249	$ 34,903
Earnings per share:
Basic	$ 0.51	$ 0.44	$ 1.25	$ 1.20
Diluted	0.51	0.44	1.24	1.19
Dividends declared per common share	$ 0.18	$ 0.17	$ 0.52	$ 0.47
Shares used in computation of earnings per share:
Basic	29,048,683	29,013,573	29,049,675	29,022,080
Impact of dilutive securities	171,814	179,765	169,862	193,112
Diluted	29,220,497	29,193,338	29,219,537	29,215,192