Acquisitions and Equity Investments - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	May 01, 2023	Dec. 31, 2022	May 01, 2022	Apr. 09, 2021
Business Acquisition [Line Items]
Contingent consideration payable	$ 0		$ 0
Contingent consideration paid	0		0			$ 12,340
RFQ hub Holdings LLC [Member]
Business Acquisition [Line Items]
Recorded investments							$ 34,400
Proportionate share in net earnings	100	$ 900	600	$ 1,100
RFQ hub Holdings LLC [Member] | Prepaid Expenses and Other Assets [Member]
Business Acquisition [Line Items]
Recorded investments	$ 36,100		$ 36,100
Muni Brokers L L C [Member]
Business Acquisition [Line Items]
Contingent consideration paid					$ 12,500		$ 8,300
Muni Brokers L L C [Member] | Accounts Payable, Accrued Expenses and Other Liabilities [Member]
Business Acquisition [Line Items]
Contingent consideration payable								$ 22,500