CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Statement [Abstract]
Net sales	$ 215,571	$ 203,190	$ 414,848	$ 375,521
Cost of goods sold	152,517	124,875	275,889	224,705
Gross profit	63,054	78,315	138,959	150,816
Selling, general, and administrative expenses	41,817	43,534	82,723	82,955
Technical and research expenses	9,973	10,276	20,235	20,408
Restructuring expenses, net	2,036	6,648	4,717	7,327
Operating income	9,228	17,857	31,284	40,126
Interest expense, net	4,285	3,691	8,613	5,929
Other expense/(income), net	1,931	(2,017)	2,135	(2,345)
Income before income taxes	3,012	16,183	20,536	36,542
Income tax expense	1,779	6,082	8,329	13,125
Net income	1,233	10,101	12,207	23,417
Net income/(loss) attributable to the noncontrolling interest	116	(266)	251	(451)
Net income attributable to the Company	$ 1,117	$ 10,367	$ 11,956	$ 23,868
Earnings per share attributable to Company shareholders - Basic	$ 0.03	$ 0.32	$ 0.37	$ 0.74
Earnings per share attributable to Company shareholders - Diluted	$ 0.03	$ 0.32	$ 0.37	$ 0.74
Shares of the Company used in computing earnings per share:
Basic	32,166	32,093	32,147	32,067
Diluted	32,200	32,131	32,182	32,106
Dividends declared per share, Class A and Class B	$ 0.17	$ 0.17	$ 0.34	$ 0.34