Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2019

The following table presents commission revenue by fee type:

	Year Ended December 31,
	2019		2018		2017
	(In thousands)

Commission revenue by fee type
Variable transaction fees
Disclosed trading	$	266,916	$	228,004	$	234,143
Open Trading - matched principal trading		98,080		65,932		45,660
U.S. Treasuries - matched principal trading		2,184		—		—
Total variable transaction fees		367,180		293,936		279,803
Distribution fees and unused minimum fees		96,676		96,898		75,479
Total commissions	$	463,856	$	390,834	$	355,282

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

	Year Ended December 31,
	2019		2018		2017
	(In thousands)

Information services revenue by timing of recognition
Services transferred over time	$	29,619	$	27,475	$	25,242
Services transferred at a point in time		1,111		752		564
Total information services revenues	$	30,730	$	28,227	$	25,806

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

	Year Ended December 31,
	2019		2018		2017
	(In thousands)
Post-trade services revenue by timing of recognition
Services transferred over time	$	15,669	$	15,013	$	9,657
Services transferred at a point in time		94		333		1,433
Total post-trade services revenues	$	15,763	$	15,346	$	11,090

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

	December 31, 2018		Payments received in advance of services to be performed		Revenue recognized for services performed during the period			Foreign Currency Translation		December 31, 2019
	(In thousands)
Information services	$	1,959	$	7,439	$	(7,260	)	$	—	$	2,138
Post-trade services		851		13,617		(13,136	)		29		1,361
Total deferred revenue	$	2,810	$	21,056	$	(20,396	)	$	29	$	3,499