Segment Information (Details 2) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Mar. 31, 2011	Dec. 31, 2010	Mar. 31, 2010	Dec. 31, 2009
Operating income (loss)
Profit sharing	$ (14,454,000)	$ (7,827,000)	$ (29,657,000)	$ (17,271,000)
Total	188,219,000	116,635,000	393,545,000	248,932,000
Assets
Cash and equivalents	277,691,000	191,593,000	277,691,000	191,593,000	160,810,000	186,513,000	225,506,000	9,008,000
Income taxes receivable	15,295,000		15,295,000			37,311,000
Deferred income taxes	21,114,000		21,114,000			20,684,000
Property, plant and equipment, net	2,176,314,000		2,176,314,000			2,213,333,000
Other	132,178,000		132,178,000			135,683,000
Total	5,900,453,000	5,545,805,000	5,900,453,000	5,545,805,000		5,589,934,000
Liabilities
Accounts payable	455,859,000		455,859,000			348,601,000
Income taxes payable	11,531,000		11,531,000			5,227,000
Deferred income taxes	476,532,000		476,532,000			457,432,000
Total	3,588,965,000	3,448,206,000	3,588,965,000	3,448,206,000
Other
Operating income (loss)
Corporate SG and A	(10,000,000)	(7,500,000)	(19,300,000)	(17,000,000)
Company-wide stock option expense	(3,700,000)	(2,900,000)	(7,400,000)	(5,200,000)
Profit sharing	(11,900,000)	(6,800,000)	(25,200,000)	(15,300,000)
Other, net	200,000	400,000	2,200,000	1,800,000
Total	(25,422,000)	(16,820,000)	(49,678,000)	(35,695,000)
Assets
Cash and equivalents	265,600,000	182,800,000	265,600,000	182,800,000
Income taxes receivable	15,300,000	35,800,000	15,300,000	35,800,000
Deferred income taxes	21,100,000	21,700,000	21,100,000	21,700,000
Property, plant and equipment, net	69,900,000	54,800,000	69,900,000	54,800,000
Debt issuance costs	21,000,000	27,000,000	21,000,000	27,000,000
Intra-company debt	153,700,000	224,800,000	153,700,000	224,800,000
Other	85,600,000	82,000,000	85,600,000	82,000,000
Total	632,242,000	628,888,000	632,242,000	628,888,000
Liabilities
Accounts payable	35,400,000	32,300,000	35,400,000	32,300,000
Income taxes payable	11,600,000	2,000,000	11,600,000	2,000,000
Accrued interest	33,700,000	33,700,000	33,700,000	33,700,000
Accrued profit sharing	25,800,000	16,800,000	25,800,000	16,800,000
Debt	2,340,900,000	2,341,100,000	2,340,900,000	2,341,100,000
Deferred income taxes	227,000,000	213,600,000	227,000,000	213,600,000
Other liabilities	65,800,000	65,900,000	65,800,000	65,900,000
Total	$ 2,740,245,000	$ 2,705,058,000	$ 2,740,245,000	$ 2,705,058,000