Trading Activities - Gross Fair Values of Derivative Instruments of Futures and Forward Contracts Traded (Detail) - USD ($)	Jun. 30, 2017	Dec. 31, 2016
Futures Contracts [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Total unrealized appreciation on open contracts	$ 1,107,221	$ 2,203,401
Total unrealized depreciation on open contracts	(2,628,562)	(827,990)
Net unrealized appreciation (depreciation) on open contracts	(1,521,341)	1,375,411
Futures Contracts [Member] \| Commodity [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Total unrealized appreciation on open contracts	580,631	864,337
Total unrealized depreciation on open contracts	(729,476)	(385,917)
Futures Contracts [Member] \| Equity [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Total unrealized appreciation on open contracts	116,814	696,575
Total unrealized depreciation on open contracts	(799,425)	(263,755)
Futures Contracts [Member] \| Currencies [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Total unrealized appreciation on open contracts	250,344	202,478
Total unrealized depreciation on open contracts	(17,194)	(55,806)
Futures Contracts [Member] \| Interest Rates [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Total unrealized appreciation on open contracts	159,432	440,011
Total unrealized depreciation on open contracts	(1,082,467)	(122,512)
Forward Contracts [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Total unrealized appreciation on open contracts	1,392,040	1,069,028
Total unrealized depreciation on open contracts	(1,557,630)	(1,116,899)
Net unrealized appreciation (depreciation) on open contracts	(165,590)	(47,871)
Forward Contracts [Member] \| Commodity [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Total unrealized appreciation on open contracts	352,452	370,551
Total unrealized depreciation on open contracts	(638,765)	(534,709)
Forward Contracts [Member] \| Currencies [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Total unrealized appreciation on open contracts	1,039,588	698,477
Total unrealized depreciation on open contracts	$ (918,865)	$ (582,190)

This element represents the excess of the cost (face amount, notional amount) of an investment (security, contract) over its fair value which deficiency has not been recognized in earnings of the entity.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 22
-URI http://asc.fasb.org/extlink&oid=50485924&loc=SL6090603-123010

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- Definition

This element represents the net excess or deficiency of the fair value of an investment (security, contract) over or under its cost (face amount, notional amount), respectively, which excess value or deficiency has not been recognized in earnings of the entity.

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