COMMITMENTS AND CONTINGENCIES - Additional Information (Detail)	9 Months Ended							9 Months Ended
	Sep. 30, 2013 USD ($)	Dec. 31, 2012 USD ($)	Sep. 30, 2013 Consolidated funds [Member] USD ($)	Dec. 31, 2012 Consolidated funds [Member] USD ($)	Sep. 30, 2013 Revolving credit facility [Member] Consolidated funds [Member] USD ($)		Dec. 31, 2012 Revolving credit facility [Member] Consolidated funds [Member] USD ($)	Sep. 30, 2013 Line of Credit [Member] Revolving credit facility [Member] Consolidated funds [Member] USD ($)	Dec. 31, 2012 Line of Credit [Member] Revolving credit facility [Member] Consolidated funds [Member] USD ($)	Dec. 20, 2012 Line of Credit [Member] Revolving credit facility [Member] Consolidated funds [Member] GBP (£)	Sep. 30, 2013 Euribor Consolidated funds [Member]
Contingencies And Commitments [Line Items]
Claims for damages	$ 800,000,000
Accrued incentives (fund level)	2,103,533,000	2,137,798,000
Compensation expense related to accrued incentives (fund level)	903,134,000	855,604,000
Capital commitments	291,945,000	265,401,000
Aggregate Potential Credit and Investment Commitments			1,137,348,000	912,001,000
Facility capacity					180,000,000					200,000,000
Line of Credit Facility, Contractual Term (in years)								3 years
Commitment fee payable on unused funds (as a percent)								1.00%
Euribor margin (as a percent)					1.75%	[1]					2.00%
Borrowings under credit facilities			$ 2,028,178,000	$ 491,625,000	$ 0		$ 38,000,000	$ 121,200,000	$ 0

[1] The facilities bear interest, at the borrower's option, at (a) an annual rate of LIBOR plus the applicable margin or (b) an alternate base rate, as defined in the respective credit agreement.