Consolidated Statements Of Operations (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Revenues:
Oil and natural gas sales	$ 104,168		$ 93,159
Processing and other	718		945
Total revenues	104,886		94,104
Operating Expenses:
Production expenses	42,748		32,767
Depreciation, depletion and amortization	30,815		24,284
Accretion of asset retirement obligations	1,732		1,322
General and administrative	10,096		9,987
Acquisition and transaction costs	561		88
Total operating expenses	85,952		68,448
Operating income (loss)	18,934		25,656
Other income (expense):
Gain (losses) on commodity derivative contracts	(16,124)		(27,024)
Interest expense, net	(11,053)		(8,778)
Total other income (expense), net	(27,059)		(33,913)
Income (loss) before income taxes	(8,125)		(8,257)
Income tax benefit (expense), net	(49)		31
Net income (loss)	(8,174)		(8,226)
Realized Gain (Loss) [Member]
Other income (expense):
Gain (losses) on commodity derivative contracts	8,165		5,768
Commodity Contract [Member]
Other income (expense):
Gain (losses) on commodity derivative contracts	(16,006)	[1]	(25,135)	[1]
Commodity Contract [Member] | Realized Gain (Loss) [Member]
Other income (expense):
Gain (losses) on commodity derivative contracts	9,310	[1]	8,071	[1]
Commodity Contract [Member] | Unrealized Gain (Loss) [Member]
Other income (expense):
Gain (losses) on commodity derivative contracts	$ (25,316)		$ (33,206)
Limited Partners - Public And Affiliated Common Units [Member]
Net loss per limited partner unit:
Unitholders' (basic and diluted) (in dollars per unit)	(0.33)		(0.49)
Weighted average number of limited partner units outstanding:
Unitholders' (basic and diluted) (in units)	58,445	[2]	28,591	[2]
Limited Partners-Affiliated - Subordinated [Member]
Net loss per limited partner unit:
Unitholders' (basic and diluted) (in dollars per unit)			(0.49)
Weighted average number of limited partner units outstanding:
Unitholders' (basic and diluted) (in units)			7,146	[2]

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

[2] For the three months ended March 31, 2013 and 2012, we had weighted average preferred units outstanding of 16,666,667. For the three months ended March 31, 2013 we had 1,860,742 Class B units outstanding. For the three months ended March 31, 2012 we had no Class B units outstanding. The preferred and Class B units are contingently convertible into common units and could potentially dilute earnings per unit in the future and have not been included in the earnings per unit calculation for the three months ended March 31, 2013 and 2012, as they were anti-dilutive for the periods.