CONSOLIDATED STATEMENTS OF MEMBERS' CAPITAL (USD $)	9 Months Ended								3 Months Ended			9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 Paid-in Capital	Sep. 30, 2011 Paid-in Capital	Sep. 30, 2012 Accumulated Earnings (Deficit)	Sep. 30, 2011 Accumulated Earnings (Deficit)	Sep. 30, 2012 Accumulated Other Comprehensive (Loss) Income	Sep. 30, 2011 Accumulated Other Comprehensive (Loss) Income	Sep. 30, 2012 Series A Preferred Unit	Mar. 31, 2012 Series A Preferred Unit	Dec. 31, 2011 Series A Preferred Unit	Sep. 30, 2012 Series A Preferred Unit	Sep. 30, 2011 Series A Preferred Unit	Sep. 30, 2012 Common Unit	Sep. 30, 2011 Common Unit
Increase (Decrease) in Stockholders' Equity
Balance	$ 871,898,000	$ 1,154,757,000	$ 62,277,000	$ 51,743,000	$ (624,121,000)	$ (313,454,000)	$ (16,279,000)	$ (30,356,000)		$ 285,168,000	$ 285,168,000	$ 285,168,000	$ 285,172,000	$ 1,164,853,000	$ 1,161,652,000
Balance (in units)	66,341,458													66,341,000	65,915,000
Balance (in units)	11,684,074									11,684,000	11,399,000	11,684,000	10,585,000
Issuance of preferred units (paid-in-kind)	26,098,000	23,644,000										26,098,000	23,644,000
Issuance of preferred units (paid-in-kind) (in units)												898,000	814,000
Accrued in-kind units	653,000	591,000										653,000	591,000
In-kind distributions	(26,751,000)	(24,235,000)							(9,138,000)	(8,698,000)	(8,486,000)	(26,751,000)	(24,235,000)
Cash distributions to common unitholders	(126,317,000)	(115,657,000)			(126,317,000)	(115,657,000)
Issuance of common units	188,083,000													188,083,000
Issuance of common units (in units)														5,750,000
Equity offering costs	(320,000)	(4,000)											(4,000)	(320,000)
Equity-based compensation	8,973,000	10,254,000	7,689,000	7,507,000										1,284,000	2,747,000
Equity-based compensation (in units)														320,000	355,000
Net loss	(97,628,000)	(163,565,000)			(97,628,000)	(163,565,000)
Derivative settlements reclassified to income	6,882,000	28,101,000					6,882,000	28,101,000
Unrealized (loss) income - change in fair value of derivatives	11,506,000	(7,658,000)					11,506,000	(7,658,000)
Balance	$ 863,077,000	$ 906,228,000	$ 69,966,000	$ 59,250,000	$ (848,066,000)	$ (592,676,000)	$ 2,109,000	$ (9,913,000)	$ 285,168,000		$ 285,168,000	$ 285,168,000	$ 285,168,000	$ 1,353,900,000	$ 1,164,399,000
Balance (in units)	72,411,407													72,411,000	66,270,000
Balance (in units)	12,582,468								12,582,000		11,684,000	12,582,000	11,399,000