Consolidated Statements of Financial Condition (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
ASSETS
Cash and securities segregated, at cost	$ 565,264	$ 476,275
Capital:
Limited partners units issued (in units)	272,301,827	273,040,452
Limited partners, units outstanding (in units)	272,301,827	273,040,452