Significant Accounting Policies - Summary of Information Services Revenue by Timing of Recognition (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Significant Accounting Policies [Line Items]
Revenues	$ 195,464	$ 168,978
Information Services [Member]
Significant Accounting Policies [Line Items]
Revenues	9,162	8,642
Information Services [Member] | Transferred over Time [Member]
Significant Accounting Policies [Line Items]
Revenues	9,045	7,806
Information Services [Member] | Transferred at a Point in Time [Member]
Significant Accounting Policies [Line Items]
Revenues	$ 117	$ 836