Divestitures - Summarizes the Assets and Liabilities of the Disposal Group Classified (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets held for sale	$ 681,327	$ 551,351
Total liabilities held for sale	216,333	107,952
Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents	145,679	159,123
Investments	23,941	24,507
Furniture and equipment, net	4,947	4,128
Other assets	153,127	107,764
Right-of-use assets	5,293	1,552
Intangible assets	4,271	4,903
Goodwill	159,826	159,826
Valuation adjustment (allowance) on disposal group	(10,150)	(7,400)
Assets held for sale	681,327	551,351
Payables: Brokers and dealers	70,927	32,983
Payables: Brokerage clients	29,281	10,232
Other liabilities	75,177	50,884
Accrued compensation and benefits	40,948	13,853
Total liabilities held for sale	216,333	107,952
Discontinued Operations, Held-for-sale | Brokers and Dealers
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Receivables, net:	96,768	44,717
Discontinued Operations, Held-for-sale | Brokerage Clients
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Receivables, net:	77,765	29,243
Discontinued Operations, Held-for-sale | Other Fees
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Receivables, net:	$ 19,860	$ 22,988