Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2021

Accounting Policies [Abstract]

Summary of Commission Revenue by Fee Type

The following table presents commission revenue by fee type:

	Three Months Ended March 31,
	2021		2020
	(In thousands)
Commission revenue by fee type
Variable transaction fees
Disclosed trading	$	98,818	$	84,245
Open Trading - matched principal trading		46,320		40,358
U.S. Treasuries - matched principal trading		3,260		4,563
Total variable transaction fees		148,398		129,166
Distribution fees and unused minimum fees		27,440		26,788
Total commissions	$	175,838	$	155,954

Summary of Information Services Revenue by Timing of Recognition

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

	Three Months Ended March 31,
	2021		2020
	(In thousands)
Information services revenue by timing of recognition
Services transferred over time	$	9,045	$	7,806
Services transferred at a point in time		117		836
Total information services revenues	$	9,162	$	8,642

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 March 31,
	2021		2020
	(In thousands)
Post-trade services revenue by timing of recognition
Services transferred over time	$	10,020	$	4,150
Services transferred at a point in time		241		3
Total post-trade services revenues	$	10,261	$	4,153

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		March 31, 2021
	(In thousands)
Information services	$	3,203	$	2,417	$	(2,454	)	$	—	$	3,166
Post-trade services		1,045		4,607		(4,003	)		10		1,659
Total deferred revenue	$	4,248	$	7,024	$	(6,457	)	$	10	$	4,825