Business Segment and Geographic Information (Operations by Geographic Area) (Details) - USD ($) $ in Thousands		3 Months Ended									12 Months Ended
		Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015		Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Segment Reporting Information [Line Items]
Net sales		$ 173,000	$ 165,259	$ 157,489	$ 160,566	$ 152,928		$ 160,366	$ 163,098	$ 165,051	$ 656,314	[1]	$ 641,443	[1]	$ 610,911	[1]
Long-Lived Assets		522,894				429,133	[2]				522,894		429,133	[2]	287,223	[2]
United States
Segment Reporting Information [Line Items]
Net sales	[1]										158,136		164,478		124,305
Long-Lived Assets		326,199				218,439	[2]				326,199		218,439	[2]	70,728	[2]
China
Segment Reporting Information [Line Items]
Net sales	[1]										236,961		227,993		236,488
Long-Lived Assets		62,728				65,994	[2]				62,728		65,994	[2]	49,794	[2]
Germany
Segment Reporting Information [Line Items]
Net sales	[1]										79,480		76,569		93,478
Long-Lived Assets		101,725				110,240	[2]				101,725		110,240	[2]	129,702	[2]
Other
Segment Reporting Information [Line Items]
Net sales	[1]										181,737		172,403		156,640
Long-Lived Assets		$ 32,242				$ 34,460	[2]				$ 32,242		$ 34,460	[2]	$ 36,999	[2]

[1] Net sales are allocated to countries based on the location of the customer.

[2] Long-lived assets are based on the location of the asset and are comprised of goodwill and other intangibles and property, plant and equipment.