Organization - Additional Information (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2018	Oct. 07, 2004	Dec. 04, 2003	Apr. 30, 2003
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				36,616
Redeemable Units per share				$ 1,000
Number of Redeemable Units authorized to be sold during initial public offering period		1,000,000	700,000	300,000
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]
Monthly ongoing selling agent fee	0.0625%
Ongoing selling agent fee	0.75%
Class A Redeemable Units [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Monthly ongoing selling agent fee	0.1667%
Ongoing selling agent fee	2.00%
Minimum [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Net asset value per unit liquidation circumstance	$ 400
Partnership liquidation date circumstance	Dec. 31, 2022