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, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Blackstone's Treasury Cash Management Strategies
Gain (Loss) on Investments [Line Items]
Realized Gains	$ 3,094	$ 3,911
Net Change in Unrealized Gains (Losses)	8,970	(971)
Total realized and net change in unrealized gains (losses)	$ 12,064	$ 2,940