Significant Accounting Policies - Summary of Post-Trade Services Revenue by Timing of Recognition (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Significant Accounting Policies [Line Items]
Revenues	$ 182,229	$ 176,334	$ 368,286	$ 371,798
Post-trade Services [Member]
Significant Accounting Policies [Line Items]
Revenues	9,144	9,848	19,056	20,109
Post-trade Services [Member] | Transferred over Time [Member]
Significant Accounting Policies [Line Items]
Revenues	9,143	9,848	19,014	20,100
Post-trade Services [Member] | Transferred at a Point in Time [Member]
Significant Accounting Policies [Line Items]
Revenues	$ 1	$ 0	$ 42	$ 9