Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Revenues
Revenues	$ 219,462	$ 197,660	$ 428,038	$ 407,978
Expenses
Employee compensation and benefits	65,237	56,790	127,153	118,054
Depreciation and amortization	19,195	18,356	37,431	36,556
Technology and communications	19,421	17,771	37,469	34,822
Professional and consulting fees	7,190	7,669	13,600	14,064
Occupancy	3,753	3,714	7,375	7,139
Marketing and advertising	2,952	3,010	5,013	4,843
Clearing costs	4,447	4,122	8,632	9,033
General and administrative	5,403	4,889	11,119	9,628
Total expenses	127,598	116,321	247,792	234,139
Operating income	91,864	81,339	180,246	173,839
Other income (expense)
Interest income	5,930	6,401	13,099	12,374
Interest expense	(139)	(621)	(352)	(937)
Equity in earnings of unconsolidated affiliate	168	354	457	724
Other, net	(407)	(1,136)	120	(2,946)
Total other income (expense)	5,552	4,998	13,324	9,215
Income before income taxes	97,416	86,337	193,570	183,054
Provision for income taxes	26,236	21,399	107,325	45,501
Net income	71,180	64,938	86,245	137,553
Less: income attributable to redeemable noncontrolling interest	31	0	31	0
Net income available for common stockholders	$ 71,149	$ 64,938	$ 86,214	$ 137,553
Net income per common share
Basic	$ 1.91	$ 1.72	$ 2.31	$ 3.65
Diluted	1.91	1.72	2.31	3.64
Cash dividends declared per common share	$ 0.76	$ 0.74	$ 1.52	$ 1.48
Weighted average shares outstanding
Basic	37,210	37,655	37,299	37,698
Diluted	37,298	37,689	37,377	37,740
Commissions [Member]
Revenues
Revenues	$ 191,770	$ 171,679	$ 373,113	$ 356,552
Information Services [Member]
Revenues
Revenues	13,087	12,544	25,991	24,425
Post-trade Services [Member]
Revenues
Revenues	11,076	10,400	22,164	21,130
Technology Services [Member]
Revenues
Revenues	$ 3,529	$ 3,037	$ 6,770	$ 5,871