Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

Summary of Commission Revenue by Fee Type

The following table presents commission revenue by fee type:

	Year Ended December 31,
	2021		2020		2019
	(In thousands)
Commission revenue by fee type
Variable transaction fees
Disclosed trading	$	333,712	$	343,427	$	266,916
Open Trading - matched principal trading		155,465		170,537		98,080
U.S. Treasuries - matched principal trading		12,400		12,372		2,184
Total variable transaction fees		501,577		526,337		367,180
Distribution fees and unused minimum fees		119,431		108,108		96,676
Total commissions	$	621,008	$	634,445	$	463,856

Summary of Information Services Revenue by Timing of Recognition

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

	Year Ended December 31,
	2021		2020		2019
	(In thousands)
Information services revenue by timing of recognition
Services transferred over time	$	37,341	$	32,425	$	29,619
Services transferred at a point in time		834		1,916		1,111
Total information services revenues	$	38,175	$	34,341	$	30,730

Summary of Post-Trade Services Revenue by Timing of Recognition

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

	Year Ended December 31,
	2021		2020		2019
	(In thousands)
Post-trade services revenue by timing of recognition
Services transferred over time	$	38,850	$	19,158	$	15,669
Services transferred at a point in time		72		302		94
Total post-trade services revenues	$	38,922	$	19,460	$	15,763

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, 2020		Payments received in advance of services to be performed		Revenue recognized for services performed during the period			Foreign Currency Translation			December 31, 2021
	(In thousands)
Information services	$	3,203	$	10,657	$	(10,332	)	$	—		$	3,528
Post-trade services		1,045		15,488		(15,801	)		(12	)		720
Total deferred revenue	$	4,248	$	26,145	$	(26,133	)	$	(12	)	$	4,248