Fees - Additional Information (Detail) (Maximum)	3 Months Ended
	Jun. 30, 2012
Other Noninterest Expense [Line Items]
Quarterly incentive fee to Advisors as percentage of New Trading Profit	20.00%
Monthly Payment Rate
Other Noninterest Expense [Line Items]
Management fee as percentage of month-end net assets	0.167%
Annual Payment Rate
Other Noninterest Expense [Line Items]
Management fee as percentage of month-end net assets	2.00%