Significant Accounting Policies - Summary of Post-Trade Services Revenue by Timing of Recognition (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Significant Accounting Policies [Line Items]
Revenues	$ 172,284	$ 172,112	$ 555,299	$ 540,398
Post-trade Services [Member]
Significant Accounting Policies [Line Items]
Revenues	9,833	9,000	29,228	28,056
Post-trade Services [Member] | Transferred over Time [Member]
Significant Accounting Policies [Line Items]
Revenues	9,774	9,000	29,126	28,014
Post-trade Services [Member] | Transferred at a Point in Time [Member]
Significant Accounting Policies [Line Items]
Revenues	$ 59	$ 0	$ 102	$ 42