Derivative Financial Instruments Fair Value (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Fair value of derivative assets and liabilities
Price Risk Derivatives, at Fair Value, Net	$ (47,200,000)	$ 21,500,000
Derivative asset current	7,450,000	21,559,000
Derivative asset noncurrent	13,886,000	30,951,000
Derivative liability current	60,684,000	26,380,000
Derivatives liability noncurrent	7,885,000	4,640,000
Derivatives not designated as hedging instruments
Fair value of derivative assets and liabilities
Derivative asset current	7,450,000	21,559,000
Derivative asset noncurrent	13,886,000	30,951,000
Derivative liability current	60,684,000	26,380,000
Derivatives liability noncurrent	7,885,000	4,640,000
Level 2 | Derivatives not designated as hedging instruments | Fair Value, Measurements, Recurring [Member]
Fair value of derivative assets and liabilities
Derivative assets not designated as hedging instruments	21,336,000	52,510,000
Derivative liabilities not designated as hedging instruments	$ 68,569,000	$ 31,020,000