Segments and Geographic Areas (Details 1) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 675,600	$ 591,300	$ 521,100
North America [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	210,200	176,900	149,000
European Union [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	233,600	214,800	194,700
Asia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	109,000	88,000	81,300
Middle East [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	59,300	50,500	41,600
Central and South America [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	51,700	51,200	44,000
Segment Geographical Groups Of Countries Group Six [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 11,800	$ 9,900	$ 10,500