Consolidated Statements Of Operations (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
Revenues:
Oil and natural gas sales	$ 64,559		$ 64,289		$ 191,722		$ 193,969
Processing and other	410		492		1,243		1,523
Total revenues	64,969		64,781		192,965		195,492
Operating Expenses:
Production expenses	24,681		24,161		73,448		65,197
Depreciation, depletion and amortization	21,298		19,965		61,428		58,295
Accretion of asset retirement obligations	915		719		2,645		2,033
General and administrative	9,232		8,338		26,345		22,577
Acquisition and transaction costs	278				1,286
Total operating expenses	56,404		53,183		165,152		148,102
Operating income	8,565		11,598		27,813		47,390
Other income (expense):
Gain (losses) on commodity derivative contracts	(45,382)		98,741		37,904		53,435
Interest expense, net	11,533		19,950		28,398		39,161
Total other income (expense), net	(53,743)		94,356		19,598		41,148
Income (loss) before income taxes	(45,178)		105,954		47,411		88,538
Income tax benefit (expense), net	171		(789)		(528)		(934)
Net income (loss)	(45,007)		105,165		46,883		87,604
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	(2,770)		(40,041)		14,893		(82,155)
Commodity Contract [Member]
Other income (expense):
Gain (losses) on commodity derivative contracts	(42,210)	[2]	114,306	[2]	47,996	[2]	80,309	[2]
Commodity Contract [Member] | Realized Gain (Loss) [Member]
Other income (expense):
Gain (losses) on commodity derivative contracts	13,375	[2]	(39,072)	[2]	35,668	[2]	(79,924)	[2]
Commodity Contract [Member] | Unrealized Gain (Loss) [Member]
Other income (expense):
Gain (losses) on commodity derivative contracts	$ (55,585)		$ 153,378		$ 12,328		$ 160,233
Limited Partners-Affiliated - Common [Member]
Net loss per limited partner unit:
Unitholders' (basic) (in dollars per unit)	$ (1.25)		$ 1.45		$ 0.49		$ 1.07
Unitholders' (diluted) (in dollars per unit)	$ (1.25)		$ 1.45		$ 0.49		$ 1.07
Weighted average number of limited partner units outstanding:
Common units (basic) (in units)	37,425	[1]	28,713	[1]	34,347	[1]	28,698	[1]
Common units (diluted) (in units)	37,425	[1]	28,713	[1]	34,347	[1]	28,698	[1]
Limited Partners-Affiliated - Subordinated [Member]
Net loss per limited partner unit:
Unitholders' (basic) (in dollars per unit)	$ (1.26)		$ 1.45		$ 0.33		$ 1.07
Unitholders' (diluted) (in dollars per unit)	$ (1.26)		$ 1.45		$ 0.33		$ 1.07

[1] For the three and nine months ended September 30, 2012, we had weighted average preferred units outstanding of 16,666,667, which are contingently convertible. These units could potentially dilute earnings per unit in the future and have not been included in the earnings per unit calculation for the three and nine months ended September 30, 2012, as they were anti-dilutive for the periods.

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