Agreements - Additional Information (Detail) - USD ($)					6 Months Ended	9 Months Ended		12 Months Ended
	Nov. 01, 2018	Oct. 01, 2018	Nov. 01, 2017	Oct. 31, 2017	Jun. 30, 2016	Sep. 30, 2018	Sep. 30, 2016	Dec. 31, 2018	Dec. 31, 2017
Investment [Line Items]
Percentage of general partnership interest								1.00%
General partner contribution in capital								$ 25,000
Percentage of monthly General Partner fee									0.08333%
Percentage of General Partner fee									1.00%
Cash held for restricted cash requirements								10,116,332	$ 4,861,056
Mesirow [Member]
Investment [Line Items]
Percentage of monthly management fee		0.08333%
Percentage of management fee		1.00%
Incentive fee, quarterly trading profits basis		15.00%
Cambridge Master Fund L.P. [Member]
Investment [Line Items]
Percentage of monthly management fee paid						0.08333%			0.125%
Percentage of management fee paid						1.00%			1.50%
Incentive fee, quarterly trading profits basis						15.00%			15.00%
ISAM SM/ISAM [Member]
Investment [Line Items]
Percentage of monthly management fee			0.08333%
Percentage of management fee			1.00%
Incentive fee, quarterly trading profits basis			25.00%
ISAM [Member]
Investment [Line Items]
Percentage of monthly management fee				0.125%
Percentage of management fee				1.50%
Incentive fee, quarterly trading profits basis				20.00%
SECOR Alpha Master Fund L.P. [Member]
Investment [Line Items]
Percentage of monthly management fee paid				0.09583%
Percentage of management fee paid				1.15%
Incentive fee, quarterly trading profits basis				25.00%
FORT LP [Member]
Investment [Line Items]
Percentage of monthly management fee paid				0.0625%
Percentage of management fee paid				0.75%
Incentive fee, quarterly trading profits basis				20.00%
CMF FORT Contrarian Master Fund LLC [Member]
Investment [Line Items]
Percentage of monthly management fee paid				0.09583%
Percentage of management fee paid				1.15%
AE Capital Master Fund [Member]
Investment [Line Items]
Percentage of monthly management fee paid				0.125%
Percentage of management fee paid				1.50%
Incentive fee, quarterly trading profits basis				20.00%
CMF Graham Capital Master Fund L.P. [Member]
Investment [Line Items]
Percentage of monthly management fee									0.14583%
Percentage of management fee									1.75%
Incentive fee, quarterly trading profits basis									20.00%
CMF Willowbridge Master Fund L.P. [Member]
Investment [Line Items]
Percentage of monthly management fee									0.125%
Percentage of management fee									1.50%
Incentive fee, quarterly trading profits basis									20.00%
CMF Aspect Master Fund L.P. [Member]
Investment [Line Items]
Percentage of monthly management fee									12.50%
Percentage of management fee									150.00%
Morgan Stanley Smith Barney Boronia I, LLC [Member]
Investment [Line Items]
Percentage of management fee									150.00%
Incentive fee, quarterly trading profits basis									20.00%
JE Moody [Member]
Investment [Line Items]
Percentage of monthly management fee							0.125%
Percentage of management fee							1.50%
Incentive fee, quarterly trading profits basis							20.00%
Termination date							Sep. 30, 2016
Altis Master [Member]
Investment [Line Items]
Percentage of monthly management fee					0.10417%
Percentage of management fee					1.25%
Commodity trading partnership termination date					Jun. 30, 2016
Incentive fee, quarterly trading profits basis					20.00%
MS&Co. [Member]
Investment [Line Items]
Cash held for restricted cash requirements								$ 10,116,332	$ 4,861,056
Percentage of allocable share								100.00%
U.S. Treasury bill maturity period								28 days
MS&Co. [Member] | Agreement with Trading Companies [Member]
Investment [Line Items]
Percentage of allocable share								80.00%
U.S. Treasury bill maturity period								28 days
U.S. Treasury bill discount rate								0.15%
Effective interest rate description								When the effective rate was less than zero, no interest was earned.
Morgan Stanley Wealth Management [Member]
Investment [Line Items]
Ongoing selling agent fee									2.00%
Morgan Stanley Wealth Management [Member] | Class A Redeemable Units [Member]
Investment [Line Items]
Ongoing selling agent fee								2.00%
Morgan Stanley Wealth Management [Member] | Class D Redeemable Units [Member]
Investment [Line Items]
Ongoing selling agent fee								0.75%
Harbor Investment Advisory, LLC [Member] | Harbor Selling Agreement [Member] | Class A Redeemable Units [Member]
Investment [Line Items]
Ongoing placement agent fees payable monthly	0.1667%
Ongoing placement agent fees payable annually	2.00%
Harbor Investment Advisory, LLC [Member] | Harbor Selling Agreement [Member] | Class D Redeemable Units [Member]
Investment [Line Items]
Ongoing placement agent fees payable monthly	0.0625%
Ongoing placement agent fees payable annually	0.75%