Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenues:
Commissions	$ 1,464,524	$ 1,281,294	$ 1,541,900
Principal transactions	368,100	365,507	327,761
Fees from related parties	15,968	14,734	14,856
Data, network and post-trade	111,470	96,389	89,963
Interest and dividend income	45,422	21,007	21,977
Other revenues	19,917	16,371	18,907
Total revenues	2,025,401	1,795,302	2,015,364
Expenses:
Compensation and employee benefits	992,603	853,165	1,271,340
Equity-based compensation and allocations of net income to limited partnership units and FPUs	355,378	251,071	256,164
Total compensation and employee benefits	1,347,981	1,104,236	1,527,504
Occupancy and equipment	162,743	157,491	188,322
Fees to related parties	32,649	25,662	24,030
Professional and consulting fees	60,398	68,775	67,884
Communications	114,143	108,096	117,502
Selling and promotion	61,884	49,215	38,048
Commissions and floor brokerage	61,523	58,277	64,708
Interest expense	77,231	57,932	69,329
Other expenses	74,278	87,431	80,888
Total expenses	1,992,830	1,717,115	2,178,215
Other income (losses), net:
Gains (losses) on divestitures and sale of investments	0	(1,029)	312,941
Gains (losses) on equity method investments	9,152	10,920	6,706
Other income (loss)	15,986	9,373	19,705
Total other income (losses), net	25,138	19,264	339,352
Income (loss) from operations before income taxes	57,709	97,451	176,501
Provision (benefit) for income taxes	18,934	38,584	23,013
Consolidated net income (loss)	38,775	58,867	153,488
Less: Net income (loss) attributable to noncontrolling interest in subsidiaries	2,510	10,155	29,481
Net income available to common stockholders	36,265	48,712	124,007
Basic earnings (loss) per share
Net income (loss) attributable to common stockholders	$ 34,070	$ 48,712	$ 124,007
Basic earnings (loss) per share (in dollars per share)	$ 0.08	$ 0.13	$ 0.33
Basic weighted-average shares of common stock outstanding (in shares)	426,436	371,561	379,215
Fully diluted earnings (loss) per share
Net income (loss) for fully diluted shares	$ 33,943	$ 63,479	$ 173,995
Fully diluted earnings (loss) per share (in dollars per share)	$ 0.07	$ 0.13	$ 0.32
Fully diluted weighted-average shares of common stock outstanding (in shares)	489,989	499,414	540,020