Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Revenues:
Commissions	$ 350,305	$ 299,430	$ 1,076,313	$ 965,636
Principal transactions	84,725	79,568	294,537	283,338
Fees from related parties	3,723	3,896	11,742	10,838
Data, network and post-trade	27,797	23,808	81,919	71,326
Interest and dividend income	10,150	4,110	28,836	15,506
Other revenues	5,994	5,755	15,294	12,143
Total revenues	482,694	416,567	1,508,641	1,358,787
Expenses:
Compensation and employee benefits	233,087	202,353	743,688	671,494
Equity-based compensation and allocations of net income to limited partnership units and FPUs	69,268	57,730	277,285	161,739
Total compensation and employee benefits	302,355	260,083	1,020,973	833,233
Occupancy and equipment	40,028	38,710	121,681	117,294
Fees to related parties	7,046	6,551	23,477	18,285
Professional and consulting fees	13,734	15,048	44,254	44,489
Communications	29,222	26,802	84,974	81,859
Selling and promotion	14,939	11,373	44,875	34,754
Commissions and floor brokerage	14,755	13,104	46,181	44,686
Interest expense	20,780	14,499	56,436	43,144
Other expenses	22,030	19,951	47,759	60,736
Total expenses	464,889	406,121	1,490,610	1,278,480
Other income (losses), net:
Gains (losses) on divestitures and sale of investments	0	(183)	0	(183)
Gains (losses) on equity method investments	2,094	3,230	6,568	8,762
Other income (loss)	3,967	5,545	1,221	6,958
Total other income (losses), net	6,061	8,592	7,789	15,537
Income (loss) from operations before income taxes	23,866	19,038	25,820	95,844
Provision (benefit) for income taxes	5,314	10,813	8,308	40,575
Consolidated net income (loss)	18,552	8,225	17,512	55,269
Less: Net income (loss) attributable to noncontrolling interest in subsidiaries	1,506	2,463	1,192	8,773
Net income (loss) available to common stockholders	17,046	5,762	16,320	46,496
Basic earnings (loss) per share
Net income (loss) attributable to common stockholders	$ 15,974	$ 5,762	$ 15,248	$ 46,496
Basic earnings (loss) per share (in dollars per share)	$ 0.03	$ 0.02	$ 0.04	$ 0.13
Basic weighted-average shares of common stock outstanding (in shares)	468,544	371,108	412,178	371,692
Fully diluted earnings (loss) per share
Net income (loss) for fully diluted shares	$ 15,989	$ 7,370	$ 15,107	$ 60,718
Fully diluted earnings (loss) per share (in dollars per share)	$ 0.03	$ 0.01	$ 0.03	$ 0.12
Fully diluted weighted-average shares of common stock outstanding (in shares)	477,545	496,985	494,545	501,958