Investment in the Funds - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
SECOR Master Fund L.P. [Member]
Investment [Line Items]
Percentage owned by partnership	15.30%	27.20%
Cambridge Master Fund L.P. [Member]
Investment [Line Items]
Percentage owned by partnership		4.90%
CMF Harbour Square Master Fund LLC [Member]
Investment [Line Items]
Percentage owned by partnership	31.30%
CMF AE Capital Master Fund LLC [Member]
Investment [Line Items]
Percentage owned by partnership	13.20%
Cambridge [Member]
Investment [Line Items]
Minimum amount of partnership assets allocated to trading advisor	2 times
Maximum [Member] | Cambridge [Member]
Investment [Line Items]
Maximum amount of partnership assets allocated to trading advisor	1.5 times
Maximum [Member] | SECOR [Member]
Investment [Line Items]
Maximum amount of partnership assets allocated to trading advisor	1.5 times
Maximum [Member] | Harbour Square [Member]
Investment [Line Items]
Maximum amount of partnership assets allocated to trading advisor	1.5 times