Inventories (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Inventories
Raw materials and supplies	$ 128,791	$ 119,550
Work in process	34,576	31,085
Finished products	87,211	89,334
Inventory reserves	(40,152)	(35,211)
Total Inventory	$ 210,426	$ 204,758