DEBT OBLIGATIONS AND CREDIT FACILITIES - Revolving Bank Credit Facilities and Term Loans Outstanding of Consolidated Funds (Parenthetical) (Detail) (Consolidated funds [Member], USD $) In Thousands, unless otherwise specified	Sep. 30, 2013		Dec. 31, 2012
Letter of Credit [Member]
Line of Credit Facility [Line Items]
Outstanding amounts	$ 63,545		$ 76,975
Credit Facilities [Member]
Line of Credit Facility [Line Items]
LIBOR margin (as a percent)	1.25%	[1],[2],[3]
Future Rate [Domain] | Credit Facilities [Member]
Line of Credit Facility [Line Items]
LIBOR margin (as a percent)	2.50%

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

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

[3] 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.