Agreements - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012
Agreements [Line Items]
Percentage of Interest on partners' contribution	1.00%
Amount of interest on partners' contribution	$ 25,000
Percentage of management fee paid to the Advisor	2.00%
Percentage of share of profit to Special Partner	20.00%
Percentage of Partnership interest on average daily equity maintained in cash for which interest is paid by CGM	80.00%
U.S. Treasury bills maturity period	30 days
Futures [Member]
Agreements [Line Items]
CGM brokerage commissions	18
Swap transactions [Member]
Agreements [Line Items]
CGM brokerage commissions	5
Options [Member]
Agreements [Line Items]
CGM brokerage commissions	$ 9