Organization - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Aug. 05, 2004
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Number of redeemable units of limited partnership interest issued and sold during initial public offering			20,872
Redeemable Units per share			$ 1,000
Maximum number of Redeemable Units sold by the Partnership		0
Class D Redeemable Units [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Limited Partner Capital Account Redeemable Unit outstanding	0
Maximum [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Percentage of partnership assets allocated	10.00%
Minimum [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Net asset value per unit liquidation circumstance	$ 400
Aggregate net assets of partnership liquidation threshold circumstance	$ 1,000,000
Partnership liquidation date circumstance	Dec. 31, 2023