Consolidated Statements of Financial Condition (Unaudited) (Parenthetical)	Sep. 30, 2018 $ / shares shares	Dec. 31, 2017 $ / shares shares
Class 0 Units [Member]
Members' capital:
Capital units, issued (in units)	152,749.135	164,393.539
Capital units, outstanding (in units)	152,749.135	164,393.539
Capital units, value (in dollars per unit) | $ / shares	142.13	140.90
Class 2 Units [Member]
Members' capital:
Capital units, issued (in units)	123,596.342	137,512.329
Capital units, outstanding (in units)	123,596.342	137,512.329
Capital units, value (in dollars per unit) | $ / shares	102.25	101.94