Significant Accounting Policies - Summary of Information Services Revenue by Timing of Recognition (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Significant Accounting Policies [Line Items]
Revenues	$ 176,334	$ 184,795	$ 371,798	$ 353,773
Information Services [Member]
Significant Accounting Policies [Line Items]
Revenues	9,844	8,427	19,006	17,069
Information Services [Member] | Transferred over Time [Member]
Significant Accounting Policies [Line Items]
Revenues	9,512	7,819	18,557	15,625
Information Services [Member] | Transferred at a Point in Time [Member]
Significant Accounting Policies [Line Items]
Revenues	$ 332	$ 608	$ 449	$ 1,444