Members' Capital and Distributions (Details) (USD $)	3 Months Ended				9 Months Ended
	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2012	Sep. 30, 2011
Members' Capital and Distributions
Amount					$ 26,751,000	$ 24,235,000
Series A Convertible Preferred Units
Members' Capital and Distributions
Issuance of preferred units (paid-in-kind), units (in shares)	314,561	306,889	299,404	292,101
Amount	$ 9,138,000	$ 8,915,000	$ 8,698,000	$ 8,486,000	$ 26,751,000	$ 24,235,000