Borrowings - Interest Expense on Broker-Dealer Facilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Line of Credit Facility [Line Items]
Interest expense	$ 99,294	$ 92,035	$ 79,969
Uncommitted facility
Line of Credit Facility [Line Items]
Interest expense	5,431	4,247	2,327
Committed facility
Line of Credit Facility [Line Items]
Interest expense	533	112	82
Overdraft facility
Line of Credit Facility [Line Items]
Interest expense	274	144	0
Broker-dealer credit facilities
Line of Credit Facility [Line Items]
Interest expense	$ 6,238	$ 4,503	$ 2,409