Condensed Statements of Financial Condition (Parenthetical) - shares	Jun. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
General Partner: units issued (in shares)	100,000	100,000
General Partner: units outstanding (in shares)	100,000	100,000
Limited partners: units issued (in shares)	97,928,820	96,361,989
Limited partners: units outstanding (in shares)	97,928,820	96,361,989