Summary of Changes in Financial Assets Measured at Fair Value for Which Level III Inputs Were Used (Detail) (Level 3, USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Balance, Beginning of Period	$ 3,004,213		$ 2,517,071		$ 3,076,466		$ 2,132,488
Transfer In Due to Consolidation and Acquisition					11,960	[1]	122,565	[1]
Transfer Out Due to Deconsolidation	(50,181)		(1,599)		(152,727)		(1,599)
Transfer In to Level III	177,145	[2]	171,916	[2]	224,363	[2]	253,608	[2]
Transfer Out of Level III	(261,283)	[2]	(59,315)	[2]	(374,151)	[2]	(103,280)	[2]
Purchases	440,730		272,441		634,410		463,320
Sales	(343,084)		(215,929)		(540,561)		(279,415)
Settlements			(186)		(1,891)		(46)
Realized Gains (Losses), Net	43,063		(11,723)		16,438		(8,454)
Changes in Unrealized Gains (Losses) Included in Earnings Related to Investments Still Held at the Reporting Date	35,361		(6,951)		151,657		86,538
Balance, End of Period	3,045,964		2,665,725		3,045,964		2,665,725
Investments Of Consolidated Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Balance, Beginning of Period	2,937,297		2,390,276		3,017,699		2,103,769
Transfer In Due to Consolidation and Acquisition							122,565	[1]
Transfer Out Due to Deconsolidation	(50,181)		(1,599)		(152,727)		(1,599)
Transfer In to Level III	177,145	[2]	171,916	[2]	224,363	[2]	253,608	[2]
Transfer Out of Level III	(259,570)	[2]	(59,315)	[2]	(372,438)	[2]	(103,280)	[2]
Purchases	308,817		232,684		436,850		320,312
Sales	(302,010)		(173,516)		(430,563)		(229,623)
Realized Gains (Losses), Net	29,476		(12,264)		1,959		(9,093)
Changes in Unrealized Gains (Losses) Included in Earnings Related to Investments Still Held at the Reporting Date	49,345		(8,026)		165,176		83,497
Balance, End of Period	2,890,319		2,540,156		2,890,319		2,540,156
Loans And Receivables
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Balance, Beginning of Period	3,867		105,004		30,663		8,555
Purchases	103,653		39,657		106,526		142,908
Sales			(41,872)		(29,462)		(49,251)
Settlements			(186)		(332)		(46)
Realized Gains (Losses), Net					43
Changes in Unrealized Gains (Losses) Included in Earnings Related to Investments Still Held at the Reporting Date	211		1,604		293		2,041
Balance, End of Period	107,731		104,207		107,731		104,207
Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Balance, Beginning of Period	63,049	[3]	21,791	[3]	28,104	[3]	20,164	[3]
Transfer In Due to Consolidation and Acquisition					11,960	[1],[3]
Transfer Out of Level III	(1,713)	[2],[3]			(1,713)	[2],[3]
Purchases	28,260	[3]	100	[3]	91,034	[3]	100	[3]
Sales	(41,074)	[3]	(541)	[3]	(80,536)	[3]	(541)	[3]
Settlements					(1,559)	[3]
Realized Gains (Losses), Net	13,587	[3]	541	[3]	14,436	[3]	639	[3]
Changes in Unrealized Gains (Losses) Included in Earnings Related to Investments Still Held at the Reporting Date	(14,195)	[3]	(529)	[3]	(13,812)	[3]	1,000	[3]
Balance, End of Period	$ 47,914	[3]	$ 21,362	[3]	$ 47,914	[3]	$ 21,362	[3]

[1] Represents the transfer into Level III of financial assets and liabilities held by CLO vehicles as a result of the acquisition of management contracts and the Harbourmaster acquisition.

[2] Transfers in and out of Level III financial assets and liabilities were due to changes in the observability of inputs used in the valuation of such assets and liabilities.

[3] Represents Blackstone's Treasury Cash Management Strategies and Other Investments.