Significant Accounting Policies - Summary of Information Services Revenue by Timing of Recognition (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Significant Accounting Policies [Line Items]
Revenues	$ 164,006	$ 131,597	$ 517,779	$ 381,578
Information Services [Member]
Significant Accounting Policies [Line Items]
Revenues	8,501	7,693	25,570	22,215
Information Services [Member] | Transferred over Time [Member]
Significant Accounting Policies [Line Items]
Revenues	8,227	7,203	23,852	21,472
Information Services [Member] | Transferred at a Point in Time [Member]
Significant Accounting Policies [Line Items]
Revenues	$ 274	$ 490	$ 1,718	$ 743