Inventories (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Inventory [Line Items]
Raw materials and supplies	$ 95,021	$ 93,014
Work in process	43,078	42,996
Finished goods	88,857	76,994
Inventories, net	226,956	213,004
Inventory Valuation Reserves	$ 5,595	$ 6,556