Consolidated Statements of Financial Condition - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
ASSETS
Cash and cash equivalents	$ 310,368	$ 270,124
Cash segregated under federal regulations	50,033
Investments, at fair value	31,274	230,477
Accounts receivable, net of allowance of $166 and $57 as of September 30, 2020 and December 31, 2019, respectively	81,706	62,017
Receivables from broker-dealers, clearing organizations and customers	380,853
Goodwill	147,388	146,861
Intangible assets, net of accumulated amortization	58,873	60,986
Furniture, equipment, leasehold improvements and capitalized software, net of accumulated depreciation and amortization	82,074	71,795
Operating lease right-of-use assets	76,692	81,399
Prepaid expenses and other assets	26,191	30,770
Deferred tax assets, net	52	501
Total assets	1,245,504	954,930
Liabilities
Accrued employee compensation	50,926	47,365
Payables to broker-dealers, clearing organizations and customers	138,120
Income and other tax liabilities	34,822	16,690
Deferred revenue	5,092	3,499
Accounts payable, accrued expenses and other liabilities	25,297	19,294
Operating lease liabilities	93,708	97,991
Total liabilities	347,965	184,839
Commitments and Contingencies (Note 13)
Stockholders' equity
Preferred stock
Common stock	122	122
Additional paid-in capital	327,646	342,541
Treasury stock - Common stock voting, at cost, 2,844,370 and 2,810,609 shares as of September 30, 2020 and December 31, 2019, respectively	(168,841)	(153,388)
Retained earnings	749,211	591,086
Accumulated other comprehensive loss	(10,599)	(10,270)
Total stockholders' equity	897,539	770,091
Total liabilities and stockholders' equity	1,245,504	954,930
Series A Preferred Stock [Member]
Stockholders' equity
Preferred stock