Property, Plant and Equipment (Details) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Property, plant and equipment
Gross property, plant and equipment	$ 3,412,446	$ 3,364,582
Less: Accumulated depreciation	(2,043,244)	(1,997,609)
Property, plant and equipment, net	1,369,202	1,366,973
Land
Property, plant and equipment
Gross property, plant and equipment	27,557	29,456
Land improvements
Property, plant and equipment
Gross property, plant and equipment	17,970	18,141
Buildings and improvements
Property, plant and equipment
Gross property, plant and equipment	192,016	196,777
Machinery and equipment
Property, plant and equipment
Gross property, plant and equipment	3,093,094	3,045,335
Uncompleted construction
Property, plant and equipment
Gross property, plant and equipment	$ 81,809	$ 74,873