CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) (USD $) In Thousands, except Per Share data	3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2011	Sep. 30, 2010 Predecessor [Member]	Sep. 30, 2010 Predecessor [Member]
Revenues:
Oil, natural gas and natural gas liquids sales	$ 28,491	$ 90,439	$ 81,659	$ 168,516
Processing and other	217	689	2,819	6,954
Total revenues	28,708	91,128	84,478	175,470
Operating expenses:
Production expenses	10,927	28,478	31,299	68,556
Depreciation, depletion and amortization	7,832	25,043	25,908	45,149
Accretion of asset retirement obligations	308	865	1,193	2,648
Management fees	0	0	2,915	7,885
Acquisition evaluation costs	0	0	155	1,197
General and administrative and other	4,092	10,869	8,547	19,177
Bargain purchase gain	0	0	1,020	0
Total operating expenses	23,159	65,255	71,037	144,612
Operating income	5,549	25,873	13,441	30,858
Other income (expense):
Equity in earnings of Ute Energy, LLC	0	0	782	1,490
Realized gains (losses) on commodity derivative instruments	3,581	(37,271)	2,219	5,132
Unrealized gains (losses) on commodity derivatives instruments	53,172	69,904	(3,501)	41,432
Gain on equity share issuance	0	0	4,064	4,064
Interest expense, net	(10,097)	(19,627)	(18,481)	(31,365)
Other income (expense)	0	0	2	(407)
Total other income (expense), net	46,656	13,006	(14,915)	20,346
Income (loss) before income taxes	52,205	38,879	(1,474)	51,204
Income tax expense	(275)	(366)	(12)	(223)
Net income (loss)	51,930	38,513	(1,486)	50,981
Less: net (loss) income attributable to noncontrolling interest	0	0	(1,389)	45,817
Net income (loss) attributable to controlling interest	51,930	38,513	(97)	5,164
Less: general partner's interest in net income	52	39
Limited partners' interest in net income	51,878	38,474
Common unitholders' interest in net income	41,540	30,829
Subordinated unitholders' interest in net income	$ 10,338	$ 7,645
Net income per limited partner unit:
Common unitholders' (basic and diluted) (in dollars per unit)	$ 1.45	$ 1.07
Subordinated unitholders' (basic and diluted) (in dollars per unit)	$ 1.45	$ 1.07
Weighted-average limited partner units outstanding:
Common units (basic and diluted) (in units)	28,713	28,698
Subordinated units (basic and diluted) (in units)	7,146	7,146