Fair Value of Each Classification of Derivative Instruments (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Derivatives, Fair Value [Line Items]
Current derivative assets	$ 6,756	$ 1,634
Current derivative liabilities	(1,859)	(17,285)
Non-current derivative liabilities	(101,911)
Non-current derivative assets		3,892
Net derivative assets/(liabilities)	(97,014)	(11,759)
Refined Products
Derivatives, Fair Value [Line Items]
Current derivative assets	630
Interest Rate Swap
Derivatives, Fair Value [Line Items]
Current derivative liabilities		(544)
Non-current derivative liabilities	(101,911)
Non-current derivative assets		3,892
Physical derivative contracts
Derivatives, Fair Value [Line Items]
Current derivative assets		1,522
Current derivative liabilities	(1,245)	(3,900)
Physical Fixed Price Derivative Contracts
Derivatives, Fair Value [Line Items]
Current derivative assets	5,292
Physical Index Derivative Contracts
Derivatives, Fair Value [Line Items]
Current derivative assets	834
Current derivative liabilities	(614)
Futures Contracts | Refined Products
Derivatives, Fair Value [Line Items]
Current derivative assets		112
Current derivative liabilities		(12,635)
Futures Contracts | Natural gas
Derivatives, Fair Value [Line Items]
Current derivative liabilities		(206)
Derivatives NOT Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Current derivative assets	9,798	38,468
Current derivative liabilities	(5,091)	(25,298)
Net derivative assets/(liabilities)	4,707	13,170
Derivatives NOT Designated as Hedging Instruments | Refined Products
Derivatives, Fair Value [Line Items]
Current derivative assets	3,594
Current derivative liabilities	(3,154)
Derivatives NOT Designated as Hedging Instruments | Physical derivative contracts
Derivatives, Fair Value [Line Items]
Current derivative assets		1,552
Current derivative liabilities	(1,304)	(3,930)
Derivatives NOT Designated as Hedging Instruments | Physical Fixed Price Derivative Contracts
Derivatives, Fair Value [Line Items]
Current derivative assets	5,351
Derivatives NOT Designated as Hedging Instruments | Physical Index Derivative Contracts
Derivatives, Fair Value [Line Items]
Current derivative assets	853
Current derivative liabilities	(633)
Derivatives NOT Designated as Hedging Instruments | Futures Contracts | Refined Products
Derivatives, Fair Value [Line Items]
Current derivative assets		36,916
Current derivative liabilities		(21,368)
Derivatives Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Current derivative assets	2,664
Current derivative liabilities	(2,474)	(30,280)
Non-current derivative liabilities	(101,911)
Non-current derivative assets		5,351
Net derivative assets/(liabilities)	(101,721)	(24,929)
Derivatives Designated as Hedging Instruments | Refined Products
Derivatives, Fair Value [Line Items]
Current derivative assets	2,664
Current derivative liabilities	(2,474)
Derivatives Designated as Hedging Instruments | Interest Rate Swap
Derivatives, Fair Value [Line Items]
Current derivative liabilities		(2,003)
Non-current derivative liabilities	(101,911)
Non-current derivative assets		5,351
Derivatives Designated as Hedging Instruments | Futures Contracts | Refined Products
Derivatives, Fair Value [Line Items]
Current derivative liabilities		(28,071)
Derivatives Designated as Hedging Instruments | Futures Contracts | Natural gas
Derivatives, Fair Value [Line Items]
Current derivative liabilities		(206)
Derivative Net Carrying Value
Derivatives, Fair Value [Line Items]
Current derivative assets	12,462	38,468
Current derivative liabilities	(7,565)	(55,578)
Non-current derivative liabilities	(101,911)
Non-current derivative assets		5,351
Net derivative assets/(liabilities)	(97,014)	(11,759)
Derivative Net Carrying Value | Refined Products
Derivatives, Fair Value [Line Items]
Current derivative assets	6,258
Current derivative liabilities	(5,628)
Derivative Net Carrying Value | Interest Rate Swap
Derivatives, Fair Value [Line Items]
Current derivative liabilities		(2,003)
Non-current derivative liabilities	(101,911)
Non-current derivative assets		5,351
Derivative Net Carrying Value | Physical derivative contracts
Derivatives, Fair Value [Line Items]
Current derivative assets		1,552
Current derivative liabilities	(1,304)	(3,930)
Derivative Net Carrying Value | Physical Fixed Price Derivative Contracts
Derivatives, Fair Value [Line Items]
Current derivative assets	5,351
Derivative Net Carrying Value | Physical Index Derivative Contracts
Derivatives, Fair Value [Line Items]
Current derivative assets	853
Current derivative liabilities	(633)
Derivative Net Carrying Value | Futures Contracts | Refined Products
Derivatives, Fair Value [Line Items]
Current derivative assets		36,916
Current derivative liabilities		(49,439)
Derivative Net Carrying Value | Futures Contracts | Natural gas
Derivatives, Fair Value [Line Items]
Current derivative liabilities		(206)
Netting Balance Sheet Adjustment
Derivatives, Fair Value [Line Items]
Current derivative assets	(5,706)	(36,834)
Current derivative liabilities	5,706	38,293
Non-current derivative assets		(1,459)
Netting Balance Sheet Adjustment | Refined Products
Derivatives, Fair Value [Line Items]
Current derivative assets	(5,628)
Current derivative liabilities	5,628
Netting Balance Sheet Adjustment | Interest Rate Swap
Derivatives, Fair Value [Line Items]
Current derivative liabilities		1,459
Non-current derivative assets		(1,459)
Netting Balance Sheet Adjustment | Physical derivative contracts
Derivatives, Fair Value [Line Items]
Current derivative assets		(30)
Current derivative liabilities	59	30
Netting Balance Sheet Adjustment | Physical Fixed Price Derivative Contracts
Derivatives, Fair Value [Line Items]
Current derivative assets	(59)
Netting Balance Sheet Adjustment | Physical Index Derivative Contracts
Derivatives, Fair Value [Line Items]
Current derivative assets	(19)
Current derivative liabilities	19
Netting Balance Sheet Adjustment | Futures Contracts | Refined Products
Derivatives, Fair Value [Line Items]
Current derivative assets		(36,804)
Current derivative liabilities		$ 36,804