Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
Net sales	$ 779,839	$ 709,868	$ 745,345
Cost of goods sold	479,271	431,182	453,710
Gross profit	300,568	278,686	291,635
Selling, general and administrative expenses	160,112	146,192	147,198
Technical, product engineering, and research expenses	40,304	44,753	59,128
Restructuring and other, net	8,376	23,846	5,759
Pension settlement expense			8,190
Operating income	91,776	63,895	71,360
Interest income	(2,077)	(1,857)	(1,541)
Interest expense	15,541	11,841	12,254
Other expense/(income), net	46	2,433	(6,853)
Income before income taxes	78,266	51,478	67,500
Income tax expense/(benefit)	25,454	(5,787)	25,751
Net income	52,812	57,265	41,749
Net income/(loss) attributable to the noncontrolling interest	79	(14)	180
Net income attributable to the Company	$ 52,733	$ 57,279	$ 41,569
Earnings per share attributable to Company shareholders - Basic	$ 1.64	$ 1.79	$ 1.31
Earnings per share attributable to Company shareholders - Diluted	1.64	1.79	1.30
Dividends declared per share, Class A and Class B	$ 0.68	$ 0.67	$ 0.63