Significant Accounting Policies - Summary of Information Services Revenue by Timing of Recognition (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Significant Accounting Policies [Line Items]
Revenues	$ 689,125	$ 511,352	$ 435,565
Information Services [Member]
Significant Accounting Policies [Line Items]
Revenues	34,341	30,730	28,227
Information Services [Member] | Transferred over Time [Member]
Significant Accounting Policies [Line Items]
Revenues	32,425	29,619	27,475
Information Services [Member] | Transferred at a Point in Time [Member]
Significant Accounting Policies [Line Items]
Revenues	$ 1,916	$ 1,111	$ 752