Condensed Consolidated Statements of Financial Condition (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Assets
Cash and cash equivalents	$ 75,012	$ 54,720
Cash collateral pledged	8,729	10,907
Securities owned, at fair value	580,963	311,039
Receivable on derivative contracts, at fair value	45,043	10,075
Securities borrowed	2,252,521	927,773
Other investments	114,551	99,483
Receivable from brokers	121,873	66,980
Fees receivable, net of allowance	46,630	45,067
Due from related parties	29,818	26,910
Fixed assets, net of accumulated depreciation and amortization of $22,876 and $21,853, respectively	28,097	26,999
Goodwill	37,240	37,240
Intangible assets, net of accumulated amortization of $25,561 and $26,610, respectively	10,613	12,094
Other assets	21,490	17,561
Consolidated Funds
Cash and cash equivalents	337	2,048
Other Investments, Consolidated Funds	198,564	187,480
Other assets	693	5,624
Total Assets	3,572,174	1,842,000
Liabilities
Securities sold, not yet purchased, at fair value	235,592	130,954
Securities sold under agreement to repurchase	0	3,657
Payable for derivative contracts, at fair value	53,353	7,674
Securities loaned	2,250,562	918,577
Payable to brokers	185,274	75,420
Compensation payable	39,456	51,807
Short-term borrowings and other debt	5,498	2,564
Convertible debt	115,549	0
Fees payable	9,009	6,324
Due to related parties	377	382
Accounts Payable, Accrued Expenses and Other Liabilities	48,064	45,290
Consolidated Funds
Capital withdrawals payable	1,431	5,222
Accounts payable, accrued expenses and other liabilities	62	549
Total Liabilities	2,944,227	1,248,420
Commitments and Contingencies (Note 13)
Redeemable non-controlling interests	92,935	85,814
Stockholders' equity
Preferred stock, par value $0.01 per share; 10,000,000 shares authorized, no shares issued and outstanding	0	0
Additional paid-in capital	763,152	737,341
(Accumulated deficit) retained earnings	(165,021)	(183,243)
Accumulated other comprehensive income (loss)	453	592
Less: Class A common stock held in treasury, at cost, 19,961,735 and 15,873,549 shares as of June 30, 2014 and December 31, 2013, respectively.	(64,732)	(48,084)
Total Stockholders' Equity	535,012	507,766
Total Liabilities and Stockholders' Equity	3,572,174	1,842,000
Common Stock Class A
Stockholders' equity
Common stock	1,160	1,160
Less: Class A common stock held in treasury, at cost, 19,961,735 and 15,873,549 shares as of June 30, 2014 and December 31, 2013, respectively.	(64,732)	(48,084)
Common Stock Class B
Stockholders' equity
Common stock	$ 0	$ 0