Summary of Significant Accounting Policies (Details 3) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Property, plant and equipment
Capitalized interest costs	$ 7,700,000	$ 5,400,000	$ 1,400,000
Present values of the asset retirement obligations	$ 89,478,000	$ 74,963,000	$ 25,257,000
Machinery and equipment
Property, plant and equipment
Estimated useful lives, low end of range (in years)	3
Estimated useful lives, high end of range (in years)	10
Land improvements and building
Property, plant and equipment
Estimated useful lives, low end of range (in years)	15
Estimated useful lives, high end of range (in years)	30
Capitalized computer systems and software implementation costs
Property, plant and equipment
Estimated useful lives, low end of range (in years)	3
Estimated useful lives, high end of range (in years)	5