Inventories (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Inventory [Line Items]
Raw materials and supplies	$ 95,208	$ 93,014
Work in process	47,123	42,996
Finished goods	81,664	76,994
Inventories, net	223,995	213,004
Inventory Valuation Reserves	$ 6,168	$ 6,556