HEDGES AND OTHER DERIVATIVE FINANCIAL INSTRUMENTS - Impact of Derivative Instruments Held by Consolidated Funds on Condensed Consolidated Statements of Operations (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Derivatives, Fair Value [Line Items]
Net Realized Gain Loss On Consolidated Funds Investments	$ 1,198,260		$ 1,074,138
Net Change In Unrealized Appreciation Depreciation On Consolidated Funds Investments	1,021,517		805,823
Not Designated as Hedging Instrument [Member] | Net Investment Hedging [Member] | Consolidated funds [Member]
Derivatives, Fair Value [Line Items]
Net realized gain (loss) on investments	(38,859)		73,480
Net change in unrealized appreciation (depreciation) on investments	165,967		(83,898)
Not Designated as Hedging Instrument [Member] | Net Investment Hedging [Member] | Consolidated funds [Member] | Total Return and Credit Default Swap [Member]
Derivatives, Fair Value [Line Items]
Net Realized Gain Loss On Consolidated Funds Investments	2,327	[1]	10,926	[1]
Net Change In Unrealized Appreciation Depreciation On Consolidated Funds Investments	12,992	[1]	17,184	[1]
Not Designated as Hedging Instrument [Member] | Net Investment Hedging [Member] | Consolidated funds [Member] | Options And Futures [Member]
Derivatives, Fair Value [Line Items]
Net Realized Gain Loss On Consolidated Funds Investments	(5,197)	[1]	(2,263)	[1]
Net Change In Unrealized Appreciation Depreciation On Consolidated Funds Investments	5,086	[1]	(264)	[1]
Not Designated as Hedging Instrument [Member] | Net Investment Hedging [Member] | Consolidated funds [Member] | Foreign Currency Forward Contract [Member]
Derivatives, Fair Value [Line Items]
Net Realized Gain Loss On Consolidated Funds Investments	(35,989)	[1]	64,817	[1]
Net Change In Unrealized Appreciation Depreciation On Consolidated Funds Investments	$ 147,889	[1]	$ (100,818)	[1]

[1] Please see note 5 for additional information.