Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Income Statement [Abstract]
Net sales	$ 234,519	$ 225,990	$ 456,880	$ 461,754
Cost of goods sold	132,791	123,010	266,606	269,302
Gross profit	101,728	102,980	190,274	192,452
Selling, general, and administrative expenses	42,009	38,543	79,203	78,649
Technical and research expenses	9,762	8,873	19,243	18,003
Restructuring expenses, net	(9)	2,837	43	3,479
Operating income	49,966	52,727	91,785	92,321
Interest expense, net	4,218	3,823	7,787	7,800
Other expense/(income), net	862	1,091	1,462	16,660
Income before income taxes	44,886	47,813	82,536	67,861
Income tax expense	13,446	15,364	23,486	27,818
Net income	31,440	32,449	59,050	40,043
Net income/(loss) attributable to the noncontrolling interest	43	95	70	(1,420)
Net income attributable to the Company	$ 31,397	$ 32,354	$ 58,980	$ 41,463
Basic earnings per share (in dollars per share)	$ 0.97	$ 1.00	$ 1.82	$ 1.28
Diluted earnings per share (in dollars per share)	$ 0.97	$ 1.00	$ 1.82	$ 1.28
Earnings Per Share, Basic and Diluted, Other Disclosures [Abstract]
Weighted average number of shares used in calculating basic net income per share (in shares)	32,375	32,328	32,363	32,320
Weighted average number of shares used in calculating diluted net income per share (in shares)	32,422	32,336	32,411	32,328
Dividends declared per share, Class A and Class B (in dollars per share)	$ 0.20	$ 0.19	$ 0.40	$ 0.38