Members' Capital (Narrative) (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Other Members Capital Account [Line Items]
Potential repurchase price of Units as percentage of holder's capital account	100.00%
Allocation of net income or net losses	100.00%
Managing Member [Member]
Other Members Capital Account [Line Items]
Operating company net income loss allocation percentage from commencement until initial closing date	99.00%
Operating company net income loss allocation percentage commencing with initial closing date	7.50%
Percentage of fund distribution	7.50%
Other Members [Member]
Other Members Capital Account [Line Items]
Members capital account, units issued	8,246,919	8,246,919
Members capital account, units outstanding	8,246,919	8,246,919	8,257,599
Operating company net income loss allocation percentage from commencement until initial closing date	1.00%
Operating company net income loss allocation percentage commencing with initial closing date	92.50%
Percentage of fund distribution	92.50%
Maximum [Member] | Other Members [Member]
Other Members Capital Account [Line Items]
Members capital account, units authorized	15,000,000	15,000,000
Maximum [Member] | Initial Member [Member]
Other Members Capital Account [Line Items]
Members capital account, units issued	50	50