Condensed Consolidated Statements of Financial Condition - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Assets
Cash and cash equivalents	$ 399,429	$ 336,535
Cash segregated under regulatory requirements	216,690	80,243
Securities owned	62,085	58,408
Marketable securities	12,772	32,064
Receivables from broker-dealers, clearing organizations, customers and related broker-dealers	2,273,726	941,866
Accrued commissions and other receivables, net	602,279	516,091
Loans, forgivable loans and other receivables from employees and partners, net	259,400	216,868
Fixed assets, net	179,324	157,169
Investments	36,661	35,403
Goodwill	560,284	504,646
Other intangible assets, net	310,751	298,779
Receivables from related parties	6,279	7,748
Other assets	472,138	246,937
Total assets	5,391,818	3,432,757
Liabilities, Redeemable Partnership Interest, and Equity
Short-term borrowings	5,219	5,162
Repurchase agreements	1,100	986
Securities loaned	12,290	15,140
Accrued compensation	205,405	195,234
Payables to broker-dealers, clearing organizations, customers and related broker-dealers	2,107,383	769,833
Payables to related parties	66,743	40,155
Accounts payable, accrued and other liabilities	1,055,082	754,819
Notes payable and other borrowings	1,062,221	763,548
Total liabilities	4,515,443	2,544,877
Commitments, contingencies and guarantees (Note 19)
Redeemable partnership interest	24,929	24,706
Stockholders’ equity:
Additional paid-in capital	2,228,854	2,208,221
Treasury stock, at cost: 50,503 and 50,270 shares of Class A common stock at June 30, 2019 and December 31, 2018, respectively	(315,210)	(314,240)
Retained deficit	(1,124,860)	(1,105,019)
Accumulated other comprehensive income (loss)	(26,390)	(24,465)
Total stockholders’ equity	766,337	768,373
Noncontrolling interest in subsidiaries	85,109	94,801
Total equity	851,446	863,174
Total liabilities, redeemable partnership interest, and equity	5,391,818	3,432,757
Class A Common Stock [Member]
Stockholders’ equity:
Common stock value	3,484	3,417
Total equity	3,484	3,417
Class B Common Stock [Member]
Stockholders’ equity:
Common stock value	459	459
Total equity	$ 459	$ 459