Trading Activities - Gross Fair Values of Derivative Instruments of Futures and Forward Contracts as Separate Assets and Liabilities (Detail) - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Futures Contracts [Member]
Derivative [Line Items]
Total unrealized appreciation on open contracts	$ 1,095,148	$ 1,455,308
Total unrealized depreciation on open contracts	(240,506)	(805,108)
Net unrealized appreciation (depreciation) on open contracts	854,642	650,200
Futures Contracts [Member] | Commodity [Member]
Derivative [Line Items]
Total unrealized appreciation on open contracts	464,203	563,455
Total unrealized depreciation on open contracts	(126,534)	(223,403)
Futures Contracts [Member] | Equity [Member]
Derivative [Line Items]
Total unrealized appreciation on open contracts	106,502	498,738
Total unrealized depreciation on open contracts	(89,136)	(133,469)
Futures Contracts [Member] | Currencies [Member]
Derivative [Line Items]
Total unrealized appreciation on open contracts	146,580	195,187
Total unrealized depreciation on open contracts	(613)	(59,373)
Futures Contracts [Member] | Interest Rates [Member]
Derivative [Line Items]
Total unrealized appreciation on open contracts	377,863	197,928
Total unrealized depreciation on open contracts	(24,223)	(388,863)
Forward Contracts [Member]
Derivative [Line Items]
Total unrealized appreciation on open contracts	1,340,048	227,718
Total unrealized depreciation on open contracts	(709,524)	(489,107)
Net unrealized appreciation (depreciation) on open contracts	630,524	(261,389)
Forward Contracts [Member] | Commodity [Member]
Derivative [Line Items]
Total unrealized appreciation on open contracts	1,127,084	123,549
Total unrealized depreciation on open contracts	(473,049)	(235,526)
Forward Contracts [Member] | Currencies [Member]
Derivative [Line Items]
Total unrealized appreciation on open contracts	212,964	104,169
Total unrealized depreciation on open contracts	$ (236,475)	$ (253,581)