Organization and General - Summary of Gross Proceeds from Sales of Units (Detail) - USD ($)		3 Months Ended	102 Months Ended
		Mar. 31, 2018	Mar. 31, 2018
Limited Partners' Capital Account [Line Items]
Total proceeds from unit sales			$ 74,233,645
Contributions Admitted To Members Capital
Limited Partners' Capital Account [Line Items]
Total proceeds from unit sales		$ 67,106,564	67,106,564
DRIP
Limited Partners' Capital Account [Line Items]
Total proceeds from unit sales			6,830,872
Premiums Admitted To Members Capital
Limited Partners' Capital Account [Line Items]
Total proceeds from unit sales	[1]		$ 296,209

[1] If a member acquired units through an unsolicited sale (i.e. without broker/dealer) the member’s capital account is credited with their capital contribution plus a premium paid by RMC equal to the amount of the sales commissions that otherwise would have been paid to a broker-dealer by RMC. This premium is reported in the year paid as taxable income to the member.