Operating Expenses - Management Fee Paid by Master Fund (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Expenses And Offering Costs [Line Items]
Management Fee	$ 1,140,124	$ 1,436,067	$ 1,513,176
Voluntary Fee Waiver	(134,132)	(168,949)	(178,022)
Net Management Fee	1,005,992	1,267,118	1,335,154
Asset Management [Member]
Operating Expenses And Offering Costs [Line Items]
Management Fee	$ 1,140,124	$ 1,436,067	$ 1,513,176