Trading Activities - Trading Gains and Losses by Market Sector on Derivative Instruments Traded (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Total trading results	$ (5,416,445)	$ 486,645	$ (1,101,968)
Currencies [Member]
Derivative [Line Items]
Total trading results	(2,332,511)	(502,493)	12,482
Energy [Member]
Derivative [Line Items]
Total trading results	2,703,797	59,510	(764,839)
Grains [Member]
Derivative [Line Items]
Total trading results	(825,218)	(618,535)	61,794
Indices [Member]
Derivative [Line Items]
Total trading results	(3,649,681)	2,388,247	11,075
Interest Rates U.S. [Member]
Derivative [Line Items]
Total trading results	265,234	(169,085)	(30,501)
Interest Rates Non-U.S. [Member]
Derivative [Line Items]
Total trading results	(129,912)	(553,886)	(423,179)
Livestock [Member]
Derivative [Line Items]
Total trading results	(203,587)	(203,797)	24,283
Metals [Member]
Derivative [Line Items]
Total trading results	(1,151,776)	203,690	(85,005)
Softs [Member]
Derivative [Line Items]
Total trading results	$ (92,791)	$ (117,006)	$ 91,922