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, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Significant Accounting Policies [Line Items]
Revenues	$ 172,112	$ 162,093	$ 540,398	$ 533,891
Post-trade Services [Member]
Significant Accounting Policies [Line Items]
Revenues	9,000	9,444	28,056	29,553
Post-trade Services [Member] | Transferred over Time [Member]
Significant Accounting Policies [Line Items]
Revenues	9,000	9,444	28,014	29,544
Post-trade Services [Member] | Transferred at a Point in Time [Member]
Significant Accounting Policies [Line Items]
Revenues	$ 0	$ 0	$ 42	$ 9