Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $)	Jun. 30, 2012	Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Purchased options on futures contracts		$ 22,525
Unrealized gain (loss) on open contracts	(347,998)	363,947
Fixed income securities	19,952,245	21,870,890
Options written on futures contracts	(34,540)	(1,006)
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Purchased options on futures contracts		22,525
Fixed income securities	19,952,245	21,870,890
Total assets	19,604,247	22,257,362
Options written on futures contracts	(34,540)	(1,006)
Total fair value	19,569,707	22,256,356
Recurring | Futures positions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized gain (loss) on open contracts	(347,998)	212,644
Recurring | Forward Currency Positions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized gain (loss) on open contracts		151,303
Recurring | Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Purchased options on futures contracts		22,525
Total assets	(347,998)	235,169
Options written on futures contracts	(34,540)	(1,006)
Total fair value	(382,538)	234,163
Recurring | Fair Value, Inputs, Level 1 | Futures positions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized gain (loss) on open contracts	(347,998)	212,644
Recurring | Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed income securities	19,952,245	21,870,890
Total assets	19,952,245	22,022,193
Total fair value	19,952,245	22,022,193
Recurring | Fair Value, Inputs, Level 2 | Forward Currency Positions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized gain (loss) on open contracts		$ 151,303