Commitment and Contingencies, Other Than Loan Commitments - Additional Information (Details)	3 Months Ended
Mar. 31, 2018 USD ($) ContractualObligation
Commitments And Contingencies Disclosure [Abstract]
Number of contractual obligations \| ContractualObligation	2
O&O expenses incurred by RMC and cash remaining to be reimbursed	$ 3,210,028
Redemptions of members' capital	$ 393,124

Total change in each class of partners' capital accounts during the year due to redemptions and adjustments to redemption value. All partners include general, limited and preferred partners.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 5
-Subparagraph (SAB Topic 4.F)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187171-122770

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Name:	us-gaap_PartnersCapitalAccountRedemptions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration