Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Measurement of assets and liabilities at fair value on a recurring basis
Derivative liability for commodity hedges	$ 2,139	$ 2,331
Derivative liability for conversion feature associated with convertible debt		26,440
Level 1 [Member]
Measurement of assets and liabilities at fair value on a recurring basis
Derivative liability for commodity hedges
Derivative liability for conversion feature associated with convertible debt
Level 2 [Member]
Measurement of assets and liabilities at fair value on a recurring basis
Derivative liability for commodity hedges	2,139	2,331
Derivative liability for conversion feature associated with convertible debt
Level 3 [Member]
Measurement of assets and liabilities at fair value on a recurring basis
Derivative liability for commodity hedges
Derivative liability for conversion feature associated with convertible debt		$ 26,440