Realized and Net Change in Unrealized Gains (Losses) on Investments Held by Blackstone's Treasury Cash Management Strategies (Detail) - Blackstone's Treasury Cash Management Strategies - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Gain (Loss) on Investments [Line Items]
Realized Losses	$ (3,159)	$ (3,003)	$ (12,404)	$ (6,606)
Net Change in Unrealized Gains (Losses)	17,689	(8,984)	32,384	(12,922)
Total realized and net change in unrealized gains (losses)	$ 14,530	$ (11,987)	$ 19,980	$ (19,528)