Trading Gain (Loss) (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Trading Activity, Gains and Losses, Net [Line Items]
Trading gain (loss)	$ (216,752)	$ (1,027,411)	$ (1,370,939)	$ (1,878,542)
Agriculture
Trading Activity, Gains and Losses, Net [Line Items]
Trading gain (loss)	(116,326)	(513,248)	(316,348)	(611,681)
Currency
Trading Activity, Gains and Losses, Net [Line Items]
Trading gain (loss)	(205,017)	(701,077)	(643,324)	(1,225,707)
Energy
Trading Activity, Gains and Losses, Net [Line Items]
Trading gain (loss)	(15,791)	(66,697)	182,210	196,021
Indices
Trading Activity, Gains and Losses, Net [Line Items]
Trading gain (loss)	(375,453)	219,316	(337,237)	266,085
Interest Rates
Trading Activity, Gains and Losses, Net [Line Items]
Trading gain (loss)	425,208	241,800	137,614	(386,676)
Metals
Trading Activity, Gains and Losses, Net [Line Items]
Trading gain (loss)	$ 70,627	$ (207,505)	$ (393,854)	$ (116,584)