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		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Derivatives, Fair Value [Line Items]
Net realized gain (loss) on investments	$ 150,047	$ (471,942)	$ 69,196	$ (141,969)
Net change in unrealized appreciation (depreciation) on investments	(101,015)	309,249	(139,419)	314,781
Total return and credit default swaps [Member]
Derivatives, Fair Value [Line Items]
Net realized gain (loss) on investments	59,313	40,914	28,849	28,187
Net change in unrealized appreciation (depreciation) on investments	38,311	(42,118)	2,189	(63,071)
Forward contracts (net) [Member]
Derivatives, Fair Value [Line Items]
Net realized gain (loss) on investments	103,052	(509,223)	40,148	(170,610)
Net change in unrealized appreciation (depreciation) on investments	(137,422)	366,568	(135,228)	356,126
Options and futures [Member]
Derivatives, Fair Value [Line Items]
Net realized gain (loss) on investments	(12,318)	(3,633)	199	454
Net change in unrealized appreciation (depreciation) on investments	$ (1,904)	$ (15,201)	$ (6,380)	$ 21,726