Property, Plant & Equipment (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 651,283,000		$ 651,283,000		$ 614,263,000
Less accumulated depreciation	(272,068,000)		(272,068,000)		(267,833,000)
Total property, plant and equipment, net	379,215,000		379,215,000		346,430,000
Depreciation expense related to property, plant and equipment	6,700,000	5,200,000	13,900,000	10,300,000
Additions to property, plant and equipment			4,000,000
Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	27,724,000		27,724,000		14,875,000
Land improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	19,419,000		19,419,000		10,379,000
Buildings [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	216,635,000		216,635,000		137,923,000
Machinery and equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	305,222,000		305,222,000		306,151,000
Furniture and fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	9,873,000		9,873,000		8,779,000
Computer equipment and software [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	58,121,000		58,121,000		16,359,000
Construction in progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 14,289,000		$ 14,289,000		$ 119,797,000