Trading Activities - Trading Gains and Losses, by Market Sector, on Derivative Instruments (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Derivative [Line Items]
Total trading results	$ 1,900,907	$ (899,778)	$ 2,711,710	$ (1,827,426)
Commodity [Member]
Derivative [Line Items]
Total trading results	(565,232)	(225,973)	(1,838,327)	(838,355)
Equity [Member]
Derivative [Line Items]
Total trading results	120,114	(121,211)	702,465	(118,610)
Currencies [Member]
Derivative [Line Items]
Total trading results	(465,769)	(682,457)	(886,590)	(681,655)
Interest Rates [Member]
Derivative [Line Items]
Total trading results	$ 2,811,794	$ 129,863	$ 4,734,162	$ (188,806)