Consolidated Condensed Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Statement [Abstract]
Net sales	$ 91,119	$ 103,542	$ 199,627	$ 208,423
Cost of sales	55,269	63,266	120,455	127,690
Gross margin	35,850	40,276	79,172	80,733
Selling, engineering and administration	23,186	25,243	50,493	51,373
Operating earnings	12,664	15,033	28,679	29,360
Interest expense, net	32	85	63	214
Other pension and postretirement costs	44	35	88	82
Earnings before income taxes	12,588	14,913	28,528	29,064
Provision for income taxes	3,054	3,555	7,140	6,882
Net earnings	$ 9,534	$ 11,358	$ 21,388	$ 22,182
Earnings per share:
Basic	$ 0.33	$ 0.39	$ 0.74	$ 0.76
Diluted	0.33	0.39	0.73	0.76
Dividends declared per common share	$ 0.17	$ 0.15	$ 0.34	$ 0.30
Shares used in computation of earnings per share:
Basic	29,047,297	29,027,887	29,046,277	29,024,543
Impact of dilutive securities	218,422	183,646	200,090	200,009
Diluted	29,265,719	29,211,533	29,246,367	29,224,552