Statements of Members' Capital (USD $)	3 Months Ended	6 Months Ended		12 Months Ended
	Jun. 30, 2012	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Increase (Decrease) in Members' Capital [Roll Forward]
Members Capital, beginning of period		$ 39,121,909	$ 42,267,776	$ 42,267,776
Investor Member Shares, outstanding, beginning of period		51,854
Net income (loss)	5,252,740	4,546,682	(1,730,072)	(3,145,867)
Distributions		(7,000,000)
Members Capital, end of period	36,668,591	36,668,591		39,121,909
Investor Member Shares, outstanding, end of period	51,854	51,854		51,854
Sponsoring Member
Increase (Decrease) in Members' Capital [Roll Forward]
Members Capital, beginning of period		959,727	959,727	959,727
Net income (loss)		0		0
Members Capital, end of period	959,727	959,727		959,727
Investor Members
Increase (Decrease) in Members' Capital [Roll Forward]
Members Capital, beginning of period		38,162,182	41,308,049	41,308,049
Investor Member Shares, outstanding, beginning of period		51,854	51,854	51,854
Net income (loss)		4,546,682		(3,145,867)
Distributions		(7,000,000)
Members Capital, end of period	$ 35,708,864	$ 35,708,864		$ 38,162,182
Investor Member Shares, outstanding, end of period	51,854	51,854		51,854