Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Cash denominated in foreign currencies	$ (53,834)	$ 54,680
Cash denominated in foreign currencies, proceeds	(72,504)	71,514
Restricted cash held for margin	2,756,546	$ 2,501,707
Uncertain tax position	$ 0
Open tax year	2015 2016 2017 2018