DEBT OBLIGATIONS AND CREDIT FACILITIES - Additional Information (Detail) (USD $)			12 Months Ended			39 Months Ended		1 Months Ended		12 Months Ended					12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Term Loan	Dec. 31, 2012 Term Loan	Dec. 31, 2012 Old Line of Credit Facility	Mar. 31, 2013 Term Loan	Jan. 31, 2011 Term Loan	Dec. 31, 2012 Senior Unsecured Credit Facilities Revolving credit facility	Jan. 31, 2011 Senior Unsecured Credit Facilities Revolving credit facility	Dec. 31, 2013 Senior Unsecured Credit Facilities Revolving credit facility	Dec. 31, 2013 Numerator	Dec. 31, 2013 Denominator	Dec. 31, 2013 Consolidated Funds Revolving credit facility		Dec. 31, 2013 Consolidated Funds Senior variable notes
Debt Instrument [Line Items]
Face Amount			$ 250,000,000	$ 250,000,000			$ 300,000,000
Old term loan, Contractual term (in years)						5 years
Credit agreement								500,000,000	250,000,000				150,000,000
Credit facility, Contractual term (in years)									3 years
Quarterly principal payments							7,500,000
Final principal payment			125,000,000			150,000,000
Senior notes, term															10 years
Eurodollar margin (as a percent)										1.00%			1.75%	[1]
Fixed interest rate as a result of interest rate swap (as a percent)			2.60%
Maximum leverage ratio for credit facilitiess											3.0	1.0
Minimum fixed charge coverage ratio for credit facilities											2.5	1.0
Loan amortization rate (as a percent)			2.50%	2.50%
Commitment fee payable on unused funds (as a percent)										0.125%
Minimum required levels of assets under management	50,000,000,000
Minimum required levels of assets under net worth	600,000,000
Line of credit facility term (in years)								5 years
Debt obligations	$ 579,464,000	$ 615,179,000	$ 218,750,000	$ 243,750,000	$ 247,500,000

[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.