Consolidated Statements of Financial Condition (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Assets
Cash and cash equivalents	$ 716,919	$ 388,409
Cash segregated under regulatory requirements	8,687	3,392
Securities owned	33,119	32,003
Marketable securities	45,002	0
Receivables from broker-dealers, clearing organizations, customers and related broker-dealers	349,915	297,688
Accrued commissions receivable, net	265,920	222,299
Loans, forgivable loans and other receivables from employees and partners, net	142,769	220,098
Fixed assets, net	127,615	141,109
Investments	17,703	25,556
Goodwill	163,339	164,874
Other intangible assets, net	18,180	20,320
Receivables from related parties	15,211	21,655
Other assets	174,984	101,536
Total assets	2,079,363	1,638,939
Liabilities, Redeemable Partnership Interest, and Equity
Accrued compensation	187,855	125,793
Securities sold, not yet purchased	2,031
Payables to broker-dealers, clearing organizations, customers and related broker-dealers	303,549	254,289
Payables to related parties	15,382	40,700
Accounts payable, accrued and other liabilities	392,525	260,462
Notes payable and collateralized borrowings	258,356	301,444
Notes payable to related parties	150,000	150,000
Total liabilities	1,309,698	1,132,688
Commitments and contingencies (Note 18)
Redeemable partnership interest	66,918	78,839
Stockholders' equity:
Additional paid-in capital	745,678	575,381
Contingent Class A common stock	12,051	18,868
Treasury stock, at cost: 21,088 and 18,041 shares of Class A common stock at December 31, 2013 and 2012, respectively	(121,753)	(110,090)
Retained deficit	(167,923)	(147,452)
Accumulated other comprehensive loss	(6,060)	(4,182)
Total stockholders' equity	464,368	334,292
Noncontrolling interest in subsidiaries	238,379	93,120
Total equity	702,747	427,412
Total liabilities, redeemable partnership interest, and equity	2,079,363	1,638,939
Class A Common Stock [Member]
Stockholders' equity:
Common stock value	2,027	1,419
Total equity	2,027	1,419
Class B Common Stock [Member]
Stockholders' equity:
Common stock value	348	348
Total equity	$ 348	$ 348