Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2019

Accounting Policies [Abstract]

Summary of Commission Revenue by Fee Type

The following table presents commission revenue by fee type for the three and six months ended June 30, 2019 and 2018:

	Three Months Ended June 30,				Six Months Ended June 30,
	2019		2018		2019		2018
	(In thousands)
Commission revenue by fee type
Variable transaction fees
Disclosed trading	$	67,308	$	56,463	$	133,364	$	122,716
Open Trading - matched principal trading		23,454		15,191		46,490		28,715
Total variable transaction fees		90,762		71,654		179,854		151,431
Distribution fees and unused minimum fees		23,362		24,459		47,030		47,454
Total commissions	$	114,124	$	96,113	$	226,884	$	198,885

Summary of Information Services Revenue by Timing of Recognition

The following table presents information services revenue by timing of recognition for the three and six months ended June 30, 2019 and 2018:

	Three Months Ended June 30,				Six Months Ended June 30,
	2019		2018		2019		2018
	(In thousands)
Information services revenue by timing of recognition
Services transferred over time	$	7,050	$	6,829	$	14,269	$	13,623
Services transferred at a point in time		106		101		253		373
Total information services revenues	$	7,156	$	6,930	$	14,522	$	13,996

Summary of Post-Trade Services Revenue by Timing of Recognition

The following table presents post-trade services revenue by timing of recognition for the three and six months ended June 30, 2019 and 2018:

	Three Months Ended June 30,				Six Months Ended June 30,
	2019		2018		2019		2018
	(In thousands)
Post-trade services revenue by timing of recognition
Services transferred over time	$	3,949	$	3,620	$	8,036	$	7,907
Services transferred at a point in time		7		—		20		289
Total post-trade services revenues	$	3,956	$	3,620	$	8,056	$	8,196

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, 2018		Payments received in advance of services to be performed		Revenue recognized for services performed during the period			Foreign Currency Translation			June 30, 2019
	(In thousands)
Information services	$	1,959	$	4,030	$	(3,618	)	$	—		$	2,371
Post-trade services		851		6,768		(6,177	)		(3	)		1,439
Total deferred revenue	$	2,810	$	10,798	$	(9,795	)	$	(3	)	$	3,810