CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Current assets
Cash and cash equivalents	$ 10,075	$ 236,001
Accounts receivable - trade, net	246,677	184,624
Derivative instruments	322,872	234,675
Other current assets	56,506	55,609
Total current assets	636,130	710,909
Noncurrent assets
Oil and natural gas properties (successful efforts method)	6,940,778	5,664,503
Less accumulated depletion and amortization	(939,264)	(719,035)
Oil and natural gas properties, successful efforts method, net	6,001,514	4,945,468
Other property and equipment	178,044	139,903
Less accumulated depreciation	(44,295)	(35,151)
Other property and equipment, net	133,749	104,752
Derivative instruments	453,541	56,895
Other noncurrent assets	109,295	115,124
Noncurrent assets, excluding property, total	562,836	172,019
Total noncurrent assets	6,698,099	5,222,239
Total assets	7,334,229	5,933,148
Current liabilities
Accounts payable and accrued expenses	344,241	219,830
Derivative instruments	3,667	12,839
Other accrued liabilities	91,823	82,439
Total current liabilities	439,731	315,108
Noncurrent liabilities
Credit facility	65,000	0
Senior notes, net	3,053,924	2,742,902
Derivative instruments	3,213	39,797
Other noncurrent liabilities	61,683	47,125
Total noncurrent liabilities	3,183,820	2,829,824
Commitments and contingencies (Note 10)
Unitholders' capital
176,708,225 units and 159,009,795 units issued and outstanding at September 30, 2011, and December 31, 2010, respectively	2,843,507	2,549,099
Accumulated income	867,171	239,117
Total unitholders' capital	3,710,678	2,788,216
Total liabilities and unitholders' capital	$ 7,334,229	$ 5,933,148