Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2025

Accounting Policies [Abstract]

Summary of Commission Revenue by Fee Type

The following table presents commission revenue by fee type:

		Three Months Ended September 30,					Nine Months Ended September 30,
		2025			2024		2025		2024
	(In thousands)
Commission revenue by fee type
Variable transaction fees
Disclosed trading	$		92,640	$		91,273	$	286,183	$	272,828
Open Trading – matched principal trading			40,590			45,137		130,961		135,756
U.S. government bonds - matched principal trading			4,129			5,525		13,987		13,384
Other			8,590			4,802		20,882		14,728
Total variable transaction fees			145,949			146,737		452,013		436,696
Distribution fees and unused minimum fees			34,222			33,655		101,271		100,248
Total commissions	$		180,171	$		180,392	$	553,284	$	536,944

Summary of Information Services Revenue by Timing of Recognition

The following table presents information services revenue by timing of recognition:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2025		2024		2025		2024
	(In thousands)
Information services revenue by timing    of recognition
Services transferred over time	$	13,334	$	12,787	$	38,888	$	36,764
Services transferred at a point in time		451		173		888		621
Total information services revenues	$	13,785	$	12,960	$	39,776	$	37,385

Summary of Post-Trade Services Revenue by Timing of Recognition

The following table presents post-trade services revenue by timing of recognition:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2025		2024		2025		2024
	(In thousands)
Post-trade services revenue by timing    of recognition
Services transferred over time	$	11,271	$	10,333	$	33,360	$	31,231
Services transferred at a point in time		22		49		97		281
Total post-trade services revenues	$	11,293	$	10,382	$	33,457	$	31,512

Summary of Technology Services Revenue by Timing of Recognition

The following table presents technology services revenue by timing of recognition:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2025		2024		2025		2024
	(In thousands)
Technology services revenue by timing    of recognition
Services transferred over time	$	3,424	$	2,972	$	9,775	$	8,826
Services transferred at a point in time		148		9		567		26
Total technology services revenues	$	3,572	$	2,981	$	10,342	$	8,852

Summary of Revenue Recognized from Contract Liabilities and Remaining Balance

The revenue recognized from contract liabilities and the remaining balance is shown below:

	December 31, 2024			Payments received in advance of services to be performed		Revenue recognized for services performed during the period			Foreign Currency Translation		September 30, 2025
		(In thousands)
Information services	$		3,302	$	11,438	$	(11,646	)	$	—	$	3,094
Post-trade services			1,286		17,261		(17,218	)		93		1,422
Technology services			415		5,953		(6,046	)		—		322
Total deferred revenue	$		5,003	$	34,652	$	(34,910	)	$	93	$	4,838