Divestitures - Summarizes the Assets and Liabilities of the Disposal Group Classified (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total assets held for sale	$ 745,471	$ 564,776
Total liabilities held for sale	239,049	153,342
Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents	319,187	153,047
Investments	13,061	17,029
Furniture and equipment, net	5,517	5,807
Other assets	154,465	104,228
Right-of-use assets	4,422	5,032
Intangible assets	3,850	4,061
Goodwill	159,826	159,826
Valuation adjustment (allowance) on disposal group	(5,950)	(6,600)
Total assets held for sale	745,471	564,776
Brokers and dealers	38,012	39,359
Brokerage clients	19,790	16,885
Other liabilities	147,911	67,938
Accrued compensation and benefits	33,336	29,160
Total liabilities held for sale	239,049	153,342
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:	55,394	32,669
Discontinued Operations, Held-for-sale | Brokerage clients
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Receivables, net:	13,256	74,351
Discontinued Operations, Held-for-sale | Other fees
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Receivables, net:	$ 22,443	$ 15,326