COMMITMENTS AND CONTINGENCIES - Additional Information (Detail)	3 Months Ended						3 Months Ended	39 Months Ended
	Mar. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Mar. 31, 2013 Consolidated funds [Member] USD ($)	Dec. 31, 2012 Consolidated funds [Member] USD ($)	Mar. 31, 2013 Revolving credit facility [Member] USD ($)		Mar. 31, 2013 Line of Credit [Member] Revolving credit facility [Member] Consolidated funds [Member] USD ($)	Mar. 31, 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 (£)	Dec. 20, 2012 Libor or Euribor [Member] Consolidated funds [Member]
Contingencies And Commitments [Line Items]
Claims for damages	$ 800,000,000
Accrued incentives (fund level)	2,270,314,000	2,137,798,000
Aggregate Potential Credit and Investment Commitments			936,169,000	912,001,000
Facility capacity					150,000,000					200,000,000
Compensation expense related to accrued incentives (fund level)	923,296,000	855,604,000
Capital commitments	254,388,000	265,401,000
Line of Credit Facility, Contractual Term								3 years
Commitment fee payable on unused funds							1.00%
LIBOR margin					1.75%	[1]					2.00%
Outstanding Borrowings							$ 27,300,000	$ 27,300,000	$ 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.