Segment Reporting (Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net Sales:
Net sales	$ 210,814	$ 208,853	$ 220,602	$ 225,930	$ 207,440	$ 203,582	$ 209,111	$ 204,311	$ 866,199	$ 824,444	$ 695,977
Long-term Assets:
Total long-term assets	239,342				255,668				239,342	255,668
North America [Member]
Net Sales:
Net sales									480,511	471,770	428,046
Long-term Assets:
Total long-term assets	86,763				89,997				86,763	89,997
South America [Member]
Net Sales:
Net sales									80,175	94,533	82,589
Long-term Assets:
Total long-term assets	45,408				58,989				45,408	58,989
Europe and Other [Member]
Net Sales:
Net sales									305,513	258,141	$ 185,342
Long-term Assets:
Total long-term assets	$ 107,171				$ 106,682				$ 107,171	$ 106,682