Manager and Other Related Parties - Summary of Organization and Offering Expenses (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020
Related Party Transactions [Abstract]
Balance, January 1		$ 1,858	$ 2,260
O&O expenses allocated		(303)	(321)
O&O expenses repaid to Members' Capital by RMC	[1]	(81)	(67)
Early withdrawal penalties applied	[2]	(16)	(14)
Balance, December 31		$ 1,458	$ 1,858

[1] RMC is obligated per the Operating Agreement to repay RMI IX for the amount of unallocated O&O expenses attributed to a member’s capital account if the member redeems prior to the 40 quarterly allocations. RMC estimated its future obligation to repay unallocated O&O expenses on scheduled redemptions as of December 31, 2021, to be approximately $28,000, which may be offset in part by early withdrawal penalties collected in future periods.

[2] The O&O expenses component of early withdrawal penalties are applied as a reduction to O&O expenses to be repaid by RMC to members’ capital on scheduled redemptions. The amounts credited are determined by the ratio between the amount of the formation loan and the amount of offering costs incurred by the company.