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
	Mar. 31, 2016	Mar. 31, 2015
Gain (Loss) on Investments [Line Items]
Realized Losses	$ (18,609)	$ (161)
Net Change in Unrealized Gains	1,783	11,111
Total realized and net change in unrealized gains (losses)	$ (16,826)	$ 10,950