Borrowings - Broker-Dealer Credit Facilities Carrying Values, Net (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Line of Credit Facility [Line Items]
Total principal of long-term borrowings	$ 1,766,755	$ 1,751,816
Deferred Debt Issuance Cost	(25,599)	(21,504)
Outstanding Borrowings, net	1,738,056	1,727,205
Broker-dealer credit facilities
Line of Credit Facility [Line Items]
Financing Available	1,060,000	1,060,000
Total principal of long-term borrowings	75,000	0
Deferred Debt Issuance Cost	(1,308)	0
Outstanding Borrowings, net	$ 73,692	$ 0
Uncommitted facility
Line of Credit Facility [Line Items]
Interest Rate	6.50%	6.50%
Financing Available	$ 400,000	$ 400,000
Total principal of long-term borrowings	35,000	0
Deferred Debt Issuance Cost	(1,308)	0
Outstanding Borrowings, net	$ 33,692	0
Uncommitted facility | Receivables from broker-dealers and clearing organizations
Line of Credit Facility [Line Items]
Deferred Debt Issuance Cost		$ (2,300)
Committed facility
Line of Credit Facility [Line Items]
Interest Rate	6.75%	6.75%
Financing Available	$ 650,000	$ 650,000
Total principal of long-term borrowings	40,000	0
Deferred Debt Issuance Cost	0	0
Outstanding Borrowings, net	$ 40,000	$ 0
Committed facility | Maximum
Line of Credit Facility [Line Items]
Interest Rate	8.00%
Overdraft facility
Line of Credit Facility [Line Items]
Interest Rate	8.83%	8.88%
Financing Available	$ 10,000	$ 10,000
Total principal of long-term borrowings	0	0
Deferred Debt Issuance Cost	0	0
Outstanding Borrowings, net	$ 0	$ 0