Segment Operating Results - Segment Contribution Footnotes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Segment Reporting Information [Line Items]
Other Revenue, net	$ 79,045	$ 88,326	$ 81,246
Technology and Information Services	146,222	120,995	106,663
Professional Fees	103,044	96,205	73,741
Revision of Prior Period, Reclassification, Adjustment
Segment Reporting Information [Line Items]
Technology and Information Services		39,521	35,060
Professional Fees		(39,521)	(35,060)
Investment Banking & Equities
Segment Reporting Information [Line Items]
Other Revenue, net	78,236	86,772	78,281
Interest expense on Notes Payable, Line of Credit and Other Financing Arrangements	24,264	16,768	16,717
Technology and Information Services	141,413	117,091	103,083
Professional Fees	98,531	91,861	69,953
Investment Banking & Equities | Revision of Prior Period, Reclassification, Adjustment
Segment Reporting Information [Line Items]
Technology and Information Services		38,536	34,146
Professional Fees		(38,536)	(34,146)
Investment Management
Segment Reporting Information [Line Items]
Other Revenue, net	809	1,554	2,965
Technology and Information Services	4,809	3,904	3,580
Professional Fees	$ 4,513	4,344	3,788
Investment Management | Revision of Prior Period, Reclassification, Adjustment
Segment Reporting Information [Line Items]
Technology and Information Services		985	914
Professional Fees		$ (985)	$ (914)