Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ 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	$ 326,076	$ 304,853	$ 609,744	$ 564,097
Cost of sales	176,276	170,674	330,278	319,664
Gross profit	149,800	134,179	279,466	244,433
Operating expenses:
Research and development and other engineering	12,191	11,055	25,573	23,316
Selling	26,834	28,687	55,361	56,799
General and administrative	38,636	41,345	77,107	80,893
Total operating expenses	77,661	81,087	158,041	161,008
Net gain on disposal of assets	(73)	(561)	(137)	(251)
Income from operations	72,212	53,653	121,562	83,676
Interest income (expense), net and other	(151)	147	(2,684)	(616)
Income before taxes	72,061	53,800	118,878	83,060
Provision for income taxes	18,582	14,223	28,573	20,821
Net income	53,479	39,577	90,305	62,239
Translation adjustment, net of tax	4,525	1,363	(3,069)	28
Unamortized pension adjustments	(213)	(100)	61	(100)
Comprehensive net income	$ 57,791	$ 40,840	$ 87,297	$ 62,167
Earnings per common share:
Basic	$ 1.23	$ 0.89	$ 2.06	$ 1.39
Diluted	$ 1.22	$ 0.88	$ 2.05	$ 1.38
Number of shares outstanding
Basic	43,471	44,671	43,787	44,772
Diluted	43,663	44,972	43,980	45,089
Cash dividends declared per common share (in dollars per share)	$ 0.23	$ 0.23	$ 0.46	$ 0.45