Reasonable Representation of Each Segment's Contribution (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012		Dec. 31, 2012
Segment Reporting Information [Line Items]
Net Revenues	$ 151,422	[1]	$ 102,798	[1]
Operating Income (Loss)	14,944		(12,143)
Income from Equity Method Investments	756		2,385
Pre-Tax Income (Loss)	15,700		(9,758)
Identifiable Segment Assets	976,489		942,117		1,145,218
Operating Expenses	125,873		98,226
Other Expenses	10,605	[2]	16,715	[2]
Investment Banking
Segment Reporting Information [Line Items]
Net Revenues	131,596	[1]	83,785	[1]
Operating Expenses	105,066		78,976
Other Expenses	9,855	[2]	16,107	[2]
Operating Income (Loss)	16,675		(11,298)
Income from Equity Method Investments	170		1,628
Pre-Tax Income (Loss)	16,845		(9,670)
Identifiable Segment Assets	526,549		449,359
Investment Management
Segment Reporting Information [Line Items]
Net Revenues	19,826	[1]	19,013	[1]
Operating Income (Loss)	(1,731)		(845)
Income from Equity Method Investments	586		757
Pre-Tax Income (Loss)	(1,145)		(88)
Identifiable Segment Assets	449,940		492,758
Operating Expenses	20,807		19,250
Other Expenses	$ 750	[2]	$ 608	[2]

[1] Net revenues include Other Revenue, net, allocated to the segments as follows: For the Three Months Ended March 31, 2013 2012 Investment Banking (A) $ 213 $ (710 ) Investment Management (B) (1,713 ) (751 ) Total Other Revenue, net $ (1,500 ) $ (1,461 ) (A) Investment Banking Other Revenue, net, includes interest expense on the Senior Notes of $1,088 and $1,070 for the three months ended March 31, 2013 and 2012, respectively. (B) Investment Management Other Revenue, net, includes interest expense on the Senior Notes of $919 and $904 for the three months ended March 31, 2013 and 2012, respectively.

[2] Other Expenses are as follows: For the Three Months Ended March 31, 2013 2012 Investment Banking Amortization of LP Units and Certain Other Awards $ 4,909 $ 4,216 Acquisition Related Compensation Charges 4,946 9,645 Intangible Asset Amortization - 2,246 Total Investment Banking 9,855 16,107 Investment Management Amortization of LP Units and Certain Other Awards 668 526 Intangible Asset Amortization 82 82 Total Investment Management 750 608 Total Other Expenses $ 10,605 $ 16,715