Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Net sales	$ 424,625	$ 433,732	$ 402,440
Cost of sales	261,097	271,383	246,694
Gross margin	163,528	162,349	155,746
Selling, engineering and administration	101,380	105,480	99,151
Operating earnings	62,148	56,869	56,595
Interest expense, net	253	1,157	789
Other pension and postretirement costs	288	19,860	973
Earnings before income taxes	61,607	35,852	54,833
Provision for income taxes	14,430	8,062	20,262
Net earnings	$ 47,177	$ 27,790	$ 34,571
Earnings per share:
Basic	$ 1.63	$ 0.96	$ 1.20
Diluted	$ 1.61	$ 0.95	$ 1.19
Shares used in computation of earnings per share:
Basic	29,028	28,993	28,927
Impact of dilutive securities	192	196	184
Diluted	29,220	29,189	29,111