Derivative Financial Instruments (Narrative) (Details) (USD $)	3 Months Ended
	Mar. 31, 2012	Dec. 31, 2011
Derivative [Line Items]
Barrels of petroleum products under NYMEX contracts	3,100,000
Energy commodity derivatives contracts, net		$ 4,914,000
Energy commodity derivatives deposits, net	41,667,000	26,917,000
Net gain estimated to be classified to interest expense	200,000
Current Liabilities [Member]
Derivative [Line Items]
Energy commodity derivatives liability, net	4,700,000
Other Noncurrent Liabilities [Member]
Derivative [Line Items]
Energy commodity derivatives non-current liability	11,700,000
NYMEX Commodity Contracts [Member]
Derivative [Line Items]
Liability Derivatives	16,400,000
Energy commodity derivatives liability, net	16,400,000
Energy commodity derivatives deposits, net	41,700,000
Barrels of crude oil designated as fair value hedges	700,000
Unrealized losses on fair value hedges	(11,600,000)
NYMEX Commodity Contracts [Member] | Tank Bottom Inventory [Member]
Derivative [Line Items]
Unrealized gain (loss) on hedged item in fair value hedge offset amount	11,700,000
NYMEX Commodity Contracts [Member] | Other Current Assets [Member]
Derivative [Line Items]
Unrealized gain (loss) on hedged item in fair value hedge offset amount	(100,000)
Butane Swap Agreements [Member]
Derivative [Line Items]
Barrels of butane	25,000.000
Energy commodity derivatives liability, net	$ 100,000