CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - 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	$ 271,133	$ 251,889	$ 796,454	$ 730,866
Cost of goods sold	167,026	159,487	495,394	469,039
Gross profit	104,107	92,402	301,060	261,827
Selling, general, and administrative expenses	39,841	39,058	121,602	117,646
Technical and research expenses	8,832	9,958	28,323	30,473
Restructuring expenses, net	(244)	2,552	1,139	13,714
Operating income	55,678	40,834	149,996	99,994
Interest expense, net	3,987	4,621	13,035	13,530
Other income, net	(1,628)	(3,151)	(1,906)	(973)
Income before income taxes	53,319	39,364	138,867	87,437
Income tax expense	13,194	11,359	35,075	21,690
Net income	40,125	28,005	103,792	65,747
Net income attributable to the noncontrolling interest	116	269	539	447
Net income attributable to the Company	$ 40,009	$ 27,736	$ 103,253	$ 65,300
Earnings per share attributable to Company shareholders - Basic	$ 1.24	$ 0.86	$ 3.20	$ 2.02
Earnings per share attributable to Company shareholders - Diluted	$ 1.24	$ 0.86	$ 3.20	$ 2.02
Shares of the Company used in computing earnings per share:
Basic	32,306	32,264	32,293	32,247
Diluted	32,317	32,280	32,305	32,263
Dividends declared per share, Class A and Class B	$ 0.18	$ 0.17	$ 0.54	$ 0.51