Consolidated Statements of Financial Condition (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
ASSETS
Cash and cash equivalents	$ 446,347	$ 451,280
Cash segregated under federal regulations	46,657	45,122
Investments, at fair value	167,213	134,861
Accounts receivable, net of allowance of $710 and $577 as of September 30, 2024 and December 31, 2023, respectively	102,760	89,839
Receivables from broker-dealers, clearing organizations and customers	474,989	687,936
Goodwill	236,706	236,706
Intangible assets, net of accumulated amortization	104,331	119,108
Furniture, equipment, leasehold improvements and capitalized software, net of accumulated depreciation and amortization	109,482	102,671
Operating lease right-of-use assets	59,998	63,045
Prepaid expenses and other assets	84,566	84,499
Total assets	1,833,049	2,015,067
Liabilities
Accrued employee compensation	52,816	60,124
Payables to broker-dealers, clearing organizations and customers	283,314	537,398
Income and other tax liabilities	2,151	7,892
Accounts payable, accrued expenses and other liabilities	33,437	37,013
Operating lease liabilities	75,077	79,677
Total liabilities	446,795	722,104
Commitments and Contingencies (Note 13)
Stockholders' equity
Preferred stock	0	0
Common stock	123	123
Additional paid-in capital	344,138	333,292
Treasury stock - Common stock voting, at cost, 3,310,174 shares and 3,041,081 shares as of September 30, 2024 and December 31, 2023, respectively	(316,524)	(260,298)
Retained earnings	1,368,661	1,244,216
Accumulated other comprehensive loss	(10,144)	(24,370)
Total stockholders' equity	1,386,254	1,292,963
Total liabilities and stockholders' equity	1,833,049	2,015,067
Series A Preferred Stock [Member]
Stockholders' equity
Preferred stock	$ 0	$ 0