Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)		3 Months Ended			12 Months Ended
	Feb. 21, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Subsequent Event [Line Items]
Creation of Units		$ 8,021,089	$ 8,748,821		$ 18,530,911	$ 51,769,691	$ 2,942,102
Redemption of Units		$ 2,650,329	$ 8,215,748	$ 9,435,886	$ 55,131,710	$ 35,928,021	66,194,330
Paid in capital redeemable shares outstanding		6,800,000	8,850,000		6,800,000	8,850,000
Limited Partners Capital Units [Member]
Subsequent Event [Line Items]
Creation of Units			$ 8,748,821		$ 18,530,911	$ 51,769,691	2,942,102
Redemption of Units		$ 2,650,329	8,215,748	$ 9,435,886	55,131,710	35,928,021	66,194,330
Limited Partners Capital Units [Member] | Limited Units [Member]
Subsequent Event [Line Items]
Creation of Units			$ 8,748,821		$ 18,530,911	$ 51,769,691	$ 2,942,102
Redemption of Units (in units)		150,000	450,000	500,000	3,100,000	1,950,000	3,450,000
Redemption of Units		$ 2,650,329	$ 8,215,748	$ 9,435,886	$ 55,131,710	$ 35,928,021	$ 66,194,330
Limited Partners Capital Units [Member] | Subsequent Event [Member] | Limited Units [Member]
Subsequent Event [Line Items]
Creation of Units	$ 0
Redemption of Units (in units)	550,000
Redemption of Units	$ 10,139,270
Paid in capital redeemable shares outstanding	6,250,050