Consolidated Statement of Members' Capital and Comprehensive Income (Loss) (Unaudited) (USD $)	6 Months Ended						3 Months Ended			6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011 Common Unit [Member]	Jun. 30, 2010 Common Unit [Member]	Jun. 30, 2010 Class D Unit [Member]	Jun. 30, 2011 Class D Unit [Member]	Jun. 30, 2011 Series A preferred units [Member]	Mar. 31, 2011 Series A preferred units [Member]	Dec. 31, 2010 Series A preferred units [Member]	Jun. 30, 2011 Series A preferred units [Member]	Jun. 30, 2011 Paid-in Capital [Member]	Jun. 30, 2010 Paid-in Capital [Member]	Jun. 30, 2011 Accumulated Earnings (Deficit) [Member]	Jun. 30, 2010 Accumulated Earnings (Deficit) [Member]	Jun. 30, 2011 Accumulated Other Comprehensive (Loss) Income [Member]	Jun. 30, 2010 Accumulated Other Comprehensive (Loss) Income [Member]	Jun. 30, 2011 Comprehensive Income [Member]	Jun. 30, 2010 Comprehensive Income [Member]
Beginning Balance	$ 1,154,757,000	$ 860,026,000	$ 1,161,652,000	$ 879,504,000	$ 112,454,000			$ 285,172,000		$ 285,172,000	$ 51,743,000	$ 42,518,000	$ (313,454,000)	$ (158,267,000)	$ (30,356,000)	$ (16,183,000)
Number of Units, Beginning Balance			65,915,000	54,670,000	3,246,000	0		10,585,000		10,585,000
Issuance of preferred of units (paid-in-kind)	15,567,000									15,567,000
Issuance of preferred of units (paid-in-kind), units							278,026	271,245	264,629	536,000
Accrued in-kind units	389,000									389,000
Conversion of Class D Units into common units				112,454,000	(112,454,000)
Conversion of Class D Units into common units, Units				3,246,000	(3,246,000)
In-kind distributions	(15,956,000)									(15,956,000)
Cash distributions to common unitholders	(76,970,000)	(70,037,000)											(76,970,000)	(70,037,000)
Issuance of Units		172,008,000		172,008,000
Issuance of Units in Units				7,446,000						10,327,022
Equity offering costs	4,000	(7,756,000)		(7,756,000)						4,000
Equity-based compensation	8,000,000	5,852,000	2,431,000	991,000							5,569,000	4,861,000
Equity-based compensation, units			311,000	201,000
Net loss	(5,829,000)	(22,371,000)											(5,829,000)	(22,371,000)			(5,829,000)	(22,371,000)
Derivative settlements reclassified to income	18,324,000	(332,000)													18,324,000	(332,000)	18,324,000	(332,000)
Unrealized gain-change in fair value of derivatives	(15,657,000)	21,337,000													(15,657,000)	21,337,000	(15,657,000)	21,337,000
Comprehensive loss																	(3,162,000)	(1,366,000)
Ending Balance	$ 1,082,621,000	$ 958,727,000	$ 1,164,083,000	$ 1,157,201,000	$ 0		$ 285,168,000		$ 285,172,000	$ 285,168,000	$ 57,312,000	$ 47,379,000	$ (396,253,000)	$ (250,675,000)	$ (27,689,000)	$ 4,822,000
Number of Units, Ending Balance			66,226,000	65,563,000	0	0	11,121,000		10,585,000	11,121,000