DEBT OBLIGATIONS AND CREDIT FACILITIES - Revolving Bank Credit Facilities and Term Loans Outstanding of Consolidated Funds (Detail)	3 Months Ended		3 Months Ended						3 Months Ended				3 Months Ended				3 Months Ended				3 Months Ended					3 Months Ended			3 Months Ended				3 Months Ended					3 Months Ended			3 Months Ended			3 Months Ended					3 Months Ended			3 Months Ended
	Mar. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Mar. 31, 2013 Multi-currency term loan [Member] USD ($)		Mar. 31, 2013 Multi-currency term loan [Member] AUD	Mar. 31, 2013 Multi-currency term loan [Member] EUR (€)	Dec. 31, 2012 Multi-currency term loan [Member] USD ($)		Mar. 31, 2013 Credit Facilities [Member] USD ($)		Dec. 31, 2012 Credit Facilities [Member] USD ($)		Mar. 31, 2013 Variable Rate Notes [Member] USD ($)		Dec. 31, 2012 Variable Rate Notes [Member] USD ($)		Mar. 31, 2013 Variable Rate Notes One [Member] USD ($)		Dec. 31, 2012 Variable Rate Notes One [Member] USD ($)		Mar. 31, 2013 Revolving credit facility [Member] USD ($)		Dec. 31, 2012 Revolving credit facility [Member] USD ($)	Mar. 31, 2013 Letter of Credit [Member] USD ($)	Dec. 31, 2012 Letter of Credit [Member] USD ($)	Mar. 31, 2013 Revolving credit facility 1 [Member] USD ($)		Dec. 31, 2012 Revolving credit facility 1 [Member] USD ($)	Mar. 31, 2013 Revolving credit facility 2 [Member] USD ($)		Dec. 31, 2012 Revolving credit facility 2 [Member] USD ($)		Mar. 31, 2013 Euro denominated revolving credit facility one [Member] USD ($)		Mar. 31, 2013 Euro denominated revolving credit facility one [Member] EUR (€)		Dec. 31, 2012 Euro denominated revolving credit facility one [Member] USD ($)	Mar. 31, 2013 Revolving credit facility 3 [Member] USD ($)		Dec. 31, 2012 Revolving credit facility 3 [Member] USD ($)	Mar. 31, 2013 Revolving Credit Facility Five [Member] USD ($)		Dec. 31, 2012 Revolving Credit Facility Five [Member] USD ($)	Mar. 31, 2013 Revolving credit facility 4 [Member] USD ($)		Dec. 31, 2012 Revolving credit facility 4 [Member] USD ($)	Mar. 31, 2013 Consolidated funds [Member] USD ($)	Dec. 31, 2012 Consolidated funds [Member] USD ($)	Mar. 31, 2013 2.50% Debt, Term Loan Two [Member] USD ($)	Dec. 31, 2012 2.50% Debt, Term Loan Two [Member] USD ($)	Mar. 31, 2013 Old Line of Credit Facility [Member] USD ($)	Mar. 31, 2013 Senior Unsecured Credit Facilities [Member] Revolving credit facility [Member] USD ($)	Mar. 31, 2013 Numerator [Member]	Mar. 31, 2013 Denominator [Member]	Mar. 31, 2013 Minimum [Member] Revolving credit facility 2 [Member] USD ($)	Mar. 31, 2013 Maximum [Member] Revolving credit facility 2 [Member] USD ($)
Line of Credit Facility [Line Items]
Debt Instrument, Face Amount																																																	$ 250,000,000
Outstanding amount			14,689,000	[1]			49,158,000	[1]	0	[2],[3]	63,000,000	[2],[3]	249,500,000	[3]	249,500,000	[3]	498,611,000	[3]	0	[3]	0		38,000,000			0		8,625,000	0	[4]	19,400,000	[4]	21,765,000				63,942,000	0		0	50,000,000		0	0		0	834,565,000	491,625,000
Facility capacity			275,000,000	[1]					750,000,000	[2],[3]			249,500,000	[3]			500,000,000	[3]			150,000,000					125,000,000			55,000,000	[4]					100,000,000			10,000,000			250,000,000			40,000,000								500,000,000
LIBOR margin			3.00%	[1],[5]					1.25%	[2],[3],[5]			1.55%	[3],[5]			1.20%	[3],[5]			1.75%	[5]				1.75%	[5]		2.00%	[4],[5]			1.75%	[5]	1.75%	[5]		2.25%	[5]		1.65%	[5]		1.50%	[5]							1.00%
Maturity			Dec. 23, 2013	[1]					Aug. 28, 2015	[2],[3]			Oct. 20, 2022	[3]			Apr. 20, 2023	[3]			Dec. 15, 2013					May 20, 2014			Sep. 15, 2013	[4]			Dec. 17, 2015		Dec. 17, 2015			Sep. 01, 2013			Mar. 22, 2015			Dec. 11, 2013
Commitment fee rate																					0.35%					0.35%			0.35%	[4]			0.30%		0.30%			0.38%			0.25%			0.30%
L/C fee																													2.00%	[4],[6]			2.00%	[6]	2.00%	[6]								1.50%	[6]
Debt obligations	608,929,000	615,179,000																																															237,500,000	243,750,000	247,500,000
Debt Instrument, Loan Amortization Rate																																																	2.50%
Commitment fee payable on unused funds																																																				0.125%
Fixed interest rate as a result of interest rate swap																																																	2.60%
Maximum leverage ratio																																																					3.0	1.0
Minimum Fixed Charge Coverage Ratio For Credit Facilities																																																					2.5	1.0
Minimum required levels of assets under management	50,000,000,000
Minimum required levels of assets under net worth	600,000,000
Final principal payment																																																	125,000,000
Outstanding amounts																								77,002,000	76,975,000
Term Loan Maturity	4 years
Initial Borrowing Capacity			221,451,000		17,660,000	26,492,000
Loan Processing Fee			4,125,000
Line of Credit Facility, Temporary Decrease in Maximum Borrowing Capacity																																																							$ 55,000,000	$ 80,000,000

[1] A four-year $275,000 aggregate principal amount term loan that consists of (a) a U.S. dollar-denominated loan in an aggregate principal amount of $221,451, (b) a euro-denominated loan in an aggregate principal amount of €26,492 and (c) an Australian dollar-denominated loan in an aggregate principal amount of A$17,660. The loan is guaranteed by the fund and, with certain limited exceptions, all of the subsidiaries of the fund, and is collateralized by both the unfunded capital commitments of the partners and, with certain exceptions, the portfolio investments of the fund and its subsidiaries. In connection with the term loan, $4,125 was paid to the administrative agent as a structuring fee and is being amortized over the 4-year life of the loan.

[2] Libor margin equals 1.25% through August 28, 2013 and 2.50% thereafter.

[3] The credit facility is collateralized by the portfolio investments and cash and cash-equivalents of the fund.

[4] Effective November 29, 2012 through March 29, 2013, the credit facility was temporarily increased from $55,000 to $80,000.

[5] 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.

[6] Certain facilities allow for the issuance of letters of credit at an applicable annual fee. As of March 31, 2013 and December 31, 2012, outstanding standby letters of credit totaled $77,002 and $76,975, respectively.