CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Net sales	$ 222,141	$ 191,272	$ 636,989	$ 566,793
Cost of goods sold	142,706	118,852	418,595	343,557
Gross profit	79,435	72,420	218,394	223,236
Selling, general, and administrative expenses	41,076	38,042	123,799	120,997
Technical and research expenses	10,553	9,232	30,788	29,640
Restructuring expenses, net	5,503	326	10,220	7,653
Operating income	22,303	24,820	53,587	64,946
Interest expense, net	4,429	3,681	13,042	9,610
Other expense/(income), net	(1,155)	242	980	(2,103)
Income before income taxes	19,029	20,897	39,565	57,439
Income tax expense	3,809	7,488	12,138	20,613
Net income	15,220	13,409	27,427	36,826
Net income/(loss) attributable to the noncontrolling interest	(49)	340	202	(111)
Net income attributable to the Company	$ 15,269	$ 13,069	$ 27,225	$ 36,937
Earnings per share attributable to Company shareholders - Basic	$ 0.47	$ 0.41	$ 0.85	$ 1.15
Earnings per share attributable to Company shareholders - Diluted	$ 0.47	$ 0.41	$ 0.85	$ 1.15
Shares of the Company used in computing earnings per share:
Basic	32,187	32,104	32,160	32,079
Diluted	32,214	32,141	32,193	32,118
Dividends declared per share, Class A and Class B	$ 0.17	$ 0.17	$ 0.51	$ 0.51