Inventories (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Inventories
Raw materials and supplies	$ 129,874	$ 119,550
Work in process	30,934	31,085
Finished products	87,327	89,334
Inventory reserves	38,509	35,211
Total Inventory	$ 209,626	$ 204,758