Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2026

Accounting Policies [Abstract]

Summary of Commission Revenue by Fee Type

The following table presents commission revenue by fee type:

		Three Months Ended June 30,					Six Months Ended June 30,
		2026			2025		2026		2025
	(In thousands)
Commission revenue by fee type
Variable transaction fees
Disclosed trading	$		93,066	$		98,088	$	197,790	$	193,543
Open Trading – matched principal trading			44,924			47,319		94,154		90,371
U.S. government bonds - matched principal trading			4,399			5,329		9,714		9,858
Other			10,309			7,337		21,006		12,292
Total variable transaction fees			152,698			158,073		322,664		306,064
Distribution fees and unused minimum fees			34,197			33,697		67,702		67,049
Total commissions	$		186,895	$		191,770	$	390,366	$	373,113

Summary of Information Services Revenue by Timing of Recognition

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

	Three Months Ended June 30,				Six Months Ended June 30,
	2026		2025		2026		2025
	(In thousands)
Information services revenue by timing    of recognition
Services transferred over time	$	14,321	$	12,856	$	27,955	$	25,554
Services transferred at a point in time		1,773		231		2,584		437
Total information services revenues	$	16,094	$	13,087	$	30,539	$	25,991

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 June 30,				Six Months Ended June 30,
	2026		2025		2026		2025
	(In thousands)
Post-trade services revenue by timing    of recognition
Services transferred over time	$	11,548	$	11,039	$	23,091	$	22,089
Services transferred at a point in time		50		37		114		75
Total post-trade services revenues	$	11,598	$	11,076	$	23,205	$	22,164

Summary of Technology Services Revenue by Timing of Recognition

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

	Three Months Ended June 30,				Six Months Ended June 30,
	2026		2025		2026		2025
	(In thousands)
Technology services revenue by timing    of recognition
Services transferred over time	$	3,609	$	3,289	$	7,211	$	6,351
Services transferred at a point in time		219		240		474		419
Total technology services revenues	$	3,828	$	3,529	$	7,685	$	6,770

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, 2025			Revenue billed in advance of services to be performed		Revenue recognized for services performed during the period			Foreign Currency Translation			June 30, 2026
		(In thousands)
Information services	$		3,343	$	8,750	$	(8,793	)	$	—		$	3,300
Post-trade services			1,376		13,121		(12,659	)		(20	)		1,818
Technology services			312		4,106		(4,126	)		—			292
Total deferred revenue	$		5,031	$	25,977	$	(25,578	)	$	(20	)	$	5,410