Investment in the Funds - Assets, Liabilities and Partners'/ Members' Capital of the Funds (Detail) - USD ($)	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Investment Holdings [Line Items]
Total Assets	$ 5,372,782	$ 6,934,368
Total Liabilities	214,960	501,270
Total Capital	5,157,822	6,433,098	$ 9,094,995	$ 13,267,660
Cambridge Master Fund L.P. [Member]
Investment Holdings [Line Items]
Total Assets	21,433,817	31,063,463
Total Liabilities	4,151,814	4,384,639
Total Capital	17,282,003	$ 26,678,824
CMF AE Capital Master Fund LLC [Member]
Investment Holdings [Line Items]
Total Assets	19,758,302
Total Liabilities	99,954
Total Capital	$ 19,658,348