Segment Information Revenues and Operating Net Assets by Geographical Areas (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 170,920	$ 188,410	$ 190,830	$ 173,370	$ 170,090	$ 182,100	$ 181,690	$ 171,150	$ 723,530	$ 705,030	$ 656,160
Long-lived Assets	710,360				656,490				710,360	656,490	679,050
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									87,420	54,920	55,290
Long-lived Assets	110,530				53,770				110,530	53,770	54,090
Asia Pacific [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									37,920	38,920	28,200
Long-lived Assets	40,720				44,230				40,720	44,230	49,800
Other Americas [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									6,290	6,170	6,570
Long-lived Assets	18,430				7,500				18,430	7,500	7,560
Non-US [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									131,630	100,010	90,060
Long-lived Assets	169,680				105,500				169,680	105,500	111,450
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									591,900	605,020	566,100
Long-lived Assets	$ 540,680				$ 550,990				$ 540,680	$ 550,990	$ 567,600