Financial Highlights - Schedule of Financial Highlights (Parenthetical) (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Schedule Of Financial Highlights [Line Items]
Weighted average units outstanding	46,545,426	43,821,699	46,463,428	43,920,005
Class C, Class I and Class W Units [Member]
Schedule Of Financial Highlights [Line Items]
Distribution and dealer manager fees payable	$ 489,000	$ 911,000	$ 489,000	$ 911,000