Segments and Geographic Information (Sales and Long-Lived Assets by Geographic Area) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 781,828	$ 793,420	$ 822,345
Long-lived assets	265,675	256,392	272,534
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	479,018	478,342	488,582
Long-lived assets	89,838	91,834	94,206
Mexico
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	93,370	100,829	107,386
Long-lived assets	87,836	89,963	93,573
All Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	209,440	214,249	226,377
Long-lived assets	$ 88,001	$ 74,595	$ 84,755