CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) (USD $) In Thousands, except Per Share data	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Revenues and other
Oil, natural gas and natural gas liquids sales	$ 302,390	$ 153,195	$ 543,097	$ 302,581
Gains (losses) on oil and natural gas derivatives	205,515	123,791	(163,961)	219,794
Marketing revenues	1,509	1,223	2,682	2,617
Other revenues	1,157	195	2,280	448
Total revenues	510,571	278,404	384,098	525,440
Expenses
Lease operating expenses	56,363	38,367	102,264	69,589
Transportation expenses	6,476	5,256	12,331	9,876
Marketing expenses	1,044	772	1,853	1,741
General and administrative expenses	31,543	23,306	62,103	47,794
Exploration costs	550	155	995	4,016
Bad debt expenses	33	(208)	(5)	(19)
Depreciation, depletion and amortization	79,345	57,941	145,711	107,132
Taxes, other than income taxes	20,318	10,391	36,045	20,591
(Gains) losses on sale of assets and other, net	977	(52)	1,591	(374)
Total expenses	196,649	135,928	362,888	260,346
Other income and (expenses)
Loss on extinguishment of debt	(9,810)	0	(94,372)	0
Interest expense, net of amounts capitalized	(62,361)	(45,969)	(125,825)	(73,622)
Losses on interest rate swaps	0	(33,245)	0	(56,407)
Other, net	(2,972)	(3,691)	(4,718)	(4,292)
Total other income and (expenses)	(75,143)	(82,905)	(224,915)	(134,321)
Income (loss) before income taxes	238,779	59,571	(203,705)	130,773
Income tax benefit (expense)	(1,670)	215	(5,868)	(5,677)
Net income (loss)	$ 237,109	$ 59,786	$ (209,573)	$ 125,096
Net income (loss) per unit
Basic	$ 1.34	$ 0.41	$ (1.25)	$ 0.90
Diluted	$ 1.33	$ 0.40	$ (1.25)	$ 0.90
Weighted average units outstanding
Basic	175,035	146,124	169,104	137,874
Diluted	175,797	146,462	169,104	138,234
Distributions declared per unit	$ 0.66	$ 0.63	$ 1.32	$ 1.26