Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Net sales	$ 900,610	$ 1,054,132	$ 982,479
Cost of goods sold	529,538	656,431	632,730
Gross profit	371,072	397,701	349,749
Selling, general and administrative expenses	163,909	163,651	156,189
Technical and research expenses	35,347	37,569	40,582
Restructuring expenses, net	5,736	2,905	15,570
Operating income	166,080	193,576	137,408
Interest income	(2,748)	(2,729)	(2,118)
Interest expense	16,332	19,650	20,242
Other (income)/expense, net	13,422	(1,557)	4,037
Income before income taxes	139,074	178,212	115,247
Income tax expense	41,831	44,829	32,228
Net income	97,243	133,383	83,019
Net income/(loss) attributable to the noncontrolling interest	(1,346)	985	128
Net income attributable to the Company	$ 98,589	$ 132,398	$ 82,891
Basic earnings per share (in dollars per share)	$ 3.05	$ 4.10	$ 2.57
Diluted earnings per share (in dollars per share)	3.05	4.10	2.57
Dividends declared per share, Class A and Class B (in dollars per share)	$ 0.77	$ 0.73	$ 0.69