Unit Capital - Additional Information (Detail) - USD ($)		3 Months Ended	6 Months Ended
	Jun. 11, 2014	Jun. 30, 2020	Jun. 30, 2020	Jun. 30, 2019
Capital Unit [Line Items]
Units Issued During the Period			905,388
Aggregate gross proceeds on units purchased			$ 2,606,000
Held Units For Minimum year	1 year
Repurchase of aggregate units		584,343	584,343
Weighted average repurchase price per unit		$ 7.914	$ 7.914
Aggregate repurchase price			$ 4,624,739	$ 7,687,796
Amount of repurchase requests pending units		$ 2,305,807	$ 2,305,807
Percentage of eligible repurchase requests fulfilled on pro rata basis		14.53%
Further Amended Unit Repurchase Program [Member]
Capital Unit [Line Items]
Unit repurchase price description			price equal to the most recently determined net asset value per unit for each class of units, as most recently disclosed by the Company in a public filing with the SEC at the time of repurchase. Repurchases for the second quarter of 2020 have been made at a price equal to $7.804 per units, which was the net asset value per unit of each class as of March 31, 2020, the most recently disclosed net asset value at the time of repurchase.
Repurchase price per unit		$ 7.804	$ 7.804
Maximum [Member]
Capital Unit [Line Items]
Percentage of Total	5.00%
Private Placement [Member]
Capital Unit [Line Items]
Units, Sold in Private Placement			322,131
Distribution Reinvestment Plan [Member]
Capital Unit [Line Items]
Units Issued During the Period			583,304
Units Issued During the Period, value			$ 4,647,000
Class C Units [Member]
Capital Unit [Line Items]
Distribution, dealer manager and service fee payable		$ 489,000	$ 489,000
Estimated net assets value per unit		$ 7.804	$ 7.804
Distribution and dealer manager fee payable, discount rate		4.00%	4.00%
Percentage of distribution and dealer manager fee per annum		0.80%	0.80%
Units Issued During the Period			31,003
Aggregate gross proceeds on units purchased			$ 1,127,988	1,169,524
Class I Units [Member]
Capital Unit [Line Items]
Estimated net assets value per unit		$ 7.804	$ 7.804
Distribution and dealer manager fee payable, discount rate		4.00%	4.00%
Percentage of distribution and dealer manager fee per annum		0.50%	0.50%
Units Issued During the Period			297,965
Aggregate gross proceeds on units purchased			$ 1,345,375	$ 1,351,762
Class W Units [Member]
Capital Unit [Line Items]
Estimated net assets value per unit		$ 7.804	$ 7.804
Distribution and dealer manager fee payable, discount rate		4.00%	4.00%
Percentage of distribution and dealer manager fee per annum		0.75%	0.75%