Fair Value (Details 2) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Commodity contracts (net)
Derivative assets and liabilities classified by the Partnership within Level 3 of the valuation hierarchy
Fair value at beginning of period	$ (35,906)	$ (7,907)	$ (14,357)	$ (11,340)
Total gain or (loss) (realized and unrealized) included in earnings	10,456	13,029	(12,537)	10,271
Settlements	3,160	226	4,604	6,417
Fair value at end of period	(22,290)	5,348	(22,290)	5,348
The amount of total gain or (loss) for the period included in earnings attributable to the change in unrealized gains or losses relating to contracts still held at end of period	10,206	10,009	(10,578)	7,551
Embedded derivatives in commodity contracts (net)
Derivative assets and liabilities classified by the Partnership within Level 3 of the valuation hierarchy
Fair value at beginning of period	(50,607)	(30,861)	(34,936)	(34,199)
Total gain or (loss) (realized and unrealized) included in earnings	(2,825)	4,183	(22,105)	5,120
Settlements	3,985	3,042	7,594	5,443
Fair value at end of period	(49,447)	(23,636)	(49,447)	(23,636)
The amount of total gain or (loss) for the period included in earnings attributable to the change in unrealized gains or losses relating to contracts still held at end of period	(2,429)	7,225	(20,277)	10,562
Interest rate contracts
Derivative assets and liabilities classified by the Partnership within Level 3 of the valuation hierarchy
Fair value at beginning of period				509
Total gain or (loss) (realized and unrealized) included in earnings				1,871
Settlements				(2,380)
Embedded derivative in debt contract
Derivative assets and liabilities classified by the Partnership within Level 3 of the valuation hierarchy
Fair value at beginning of period		(134)		(190)
Total gain or (loss) (realized and unrealized) included in earnings		3		59
Fair value at end of period		(131)		(131)
The amount of total gain or (loss) for the period included in earnings attributable to the change in unrealized gains or losses relating to contracts still held at end of period		$ 3		$ 59