Price Risk Management Assets And Liabilities (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
General Discussion of Derivative Instruments and Hedging Activities [Abstract]
Expected gains on commodity derivatives	$ 11,600,000		$ 11,600,000
Unrealized gains (losses) on commodity derivatives	700,000	12,500,000	2,800,000	(32,800,000)
Deposit Assets	56,435,000		56,435,000		52,192,000
Unrealized gains (losses) on commodity derivatives and related hedged inventory	$ (7,100,000)	$ 8,200,000	$ (1,300,000)	$ (35,300,000)