Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Net sales	$ 309,932	$ 284,178	$ 874,029	$ 836,964
Cost of sales	172,288	150,282	491,952	454,881
Gross profit	137,644	133,896	382,077	382,083
Operating expenses:
Research and development and other engineering	11,972	10,441	35,287	32,840
Selling	27,672	26,879	84,471	83,653
General and administrative	37,047	37,358	117,941	113,565
Total operating expenses	76,691	74,678	237,699	230,058
Net gain on disposal of assets	(14)	(460)	(265)	(1,769)
Income from operations	60,967	59,678	144,643	153,794
Interest income (expense), net and other	(1,778)	1,156	(2,394)	284
Income before taxes	59,189	60,834	142,249	154,078
Provision for income taxes	15,503	16,473	36,324	40,202
Net income	43,686	44,361	105,925	113,876
Translation adjustment	(5,797)	2,950	(5,825)	10,533
Unamortized pension adjustments	(362)	0	(462)	0
Comprehensive net income	$ 49,121	$ 41,411	$ 111,288	$ 103,343
Earnings per common share:
Basic	$ 0.98	$ 0.96	$ 2.37	$ 2.46
Diluted	$ 0.97	$ 0.95	$ 2.35	$ 2.43
Number of shares outstanding
Basic	44,477	46,192	44,673	46,375
Diluted	44,814	46,622	44,995	46,770
Cash dividends declared per common share (in dollars per share)	$ 0.23	$ 0.22	$ 0.68	$ 0.65