Consolidated Statements Of Operations (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011
Revenues:
Oil and natural gas sales	$ 61,834		$ 67,327		$ 127,163		$ 129,680
Processing and other	375		553		833		1,031
Total revenues	62,209		67,880		127,996		130,711
Operating Expenses:
Production expenses	25,747		21,238		48,767		41,036
Depreciation, depletion and amortization	20,540		19,421		40,130		38,330
Accretion of asset retirement obligations	887		666		1,730		1,314
General and administrative	8,771		7,690		17,113		14,239
Acquisition and transaction costs	920				1,008
Total operating expenses	56,865		49,015		108,748		94,919
Operating income	5,344		18,865		19,248		35,792
Other income (expense):
Gain (losses) on commodity derivative contracts	98,875		14,446		83,288		(45,306)
Interest expense, net	9,393		15,820		16,865		19,211
Total other income (expense), net	94,511		10,479		73,341		(53,208)
Income (loss) before income taxes	99,855		29,344		92,589		(17,416)
Income tax expense, net	(730)		(356)		(699)		(145)
Net income (loss)	99,125		28,988		91,890		(17,561)
Weighted average number of limited partner units outstanding:
Subordinated units (basic and diluted) (in units)	7,146	[1]	7,146	[1]	7,146	[1]	7,146	[1]
Realized Gain (Loss) [Member]
Other income (expense):
Gain (losses) on commodity derivative contracts	11,896		(43,109)		17,664		(42,114)
Commodity Contract [Member]
Other income (expense):
Gain (losses) on commodity derivative contracts	103,904	[2]	26,299	[2]	90,206	[2]	(33,997)	[2]
Commodity Contract [Member] | Realized Gain (Loss) [Member]
Other income (expense):
Gain (losses) on commodity derivative contracts	14,222	[2]	(42,161)	[2]	22,293	[2]	(40,852)	[2]
Commodity Contract [Member] | Unrealized Gain (Loss) [Member]
Other income (expense):
Gain (losses) on commodity derivative contracts	$ 89,682		$ 68,460		$ 67,913		$ 6,855
Limited Partners-Affiliated - Common [Member]
Net loss per limited partner unit:
Unitholders' (basic) (in dollars per unit)	$ 2.15		$ 0.44		$ 1.92		$ (0.38)
Unitholders' (diluted) (in dollars per unit)	$ 1.67		$ 0.44		$ 1.60		$ (0.38)
Weighted average number of limited partner units outstanding:
Common units (basic) (in units)	36,114	[1]	28,723	[1]	32,486	[1]	28,518	[1]
Common units (diluted) (in units)	52,780	[1]	28,723	[1]	49,153	[1]	28,518	[1]
Limited Partners-Affiliated - Subordinated [Member]
Net loss per limited partner unit:
Unitholders' (basic) (in dollars per unit)	$ 2.12		$ 0.44		$ 1.76		$ (0.38)
Unitholders' (diluted) (in dollars per unit)	$ 1.65		$ 0.44		$ 1.50		$ (0.38)

[1] For the three and six months ended June 30, 2012, we had weighted average preferred units outstanding of 16,666,667, which are contingently convertible. These units have a dilutive effect on earnings per unit and have been included in the earnings per share calculation for the three and six months ended June 30, 2012.

[2] Gain (loss) on commodity derivative contracts is located in other income (expense) in the consolidated statement of operations.