Segment Operating Results - Segment Expense Footnotes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Segment Reporting Information [Line Items]
Occupancy and Equipment Rental	$ 108,784	$ 90,953	$ 84,329
Professional Fees	103,044	96,205	73,741
Travel and Related Expenses	95,612	79,446	64,527
Technology and Information Services	146,222	120,995	106,663
Depreciation and Amortization	32,557	24,468	24,348
Execution, Clearing and Custody Fees	12,499	13,211	12,275
Acquisition and Transition Costs	9,858	0	0
Other Operating Expenses	56,468	46,060	41,135
Non-Compensation	565,044	471,338	407,018
Revision of Prior Period, Reclassification, Adjustment
Segment Reporting Information [Line Items]
Professional Fees		(39,521)	(35,060)
Technology and Information Services		39,521	35,060
Investment Banking & Equities
Segment Reporting Information [Line Items]
Occupancy and Equipment Rental	106,309	88,604	82,180
Professional Fees	98,531	91,861	69,953
Travel and Related Expenses	94,515	78,519	63,798
Technology and Information Services	141,413	117,091	103,083
Depreciation and Amortization	32,098	24,141	23,943
Execution, Clearing and Custody Fees	10,654	11,487	10,724
Acquisition and Transition Costs	9,858	0	0
Other Operating Expenses	54,926	44,554	39,627
Non-Compensation	548,304	456,257	393,308
Investment Banking & Equities | Revision of Prior Period, Reclassification, Adjustment
Segment Reporting Information [Line Items]
Professional Fees		(38,536)	(34,146)
Technology and Information Services		38,536	34,146
Investment Management
Segment Reporting Information [Line Items]
Occupancy and Equipment Rental	2,475	2,349	2,149
Professional Fees	4,513	4,344	3,788
Travel and Related Expenses	1,097	927	729
Technology and Information Services	4,809	3,904	3,580
Depreciation and Amortization	459	327	405
Execution, Clearing and Custody Fees	1,845	1,724	1,551
Other Operating Expenses	1,542	1,506	1,508
Non-Compensation	$ 16,740	15,081	13,710
Investment Management | Revision of Prior Period, Reclassification, Adjustment
Segment Reporting Information [Line Items]
Professional Fees		(985)	(914)
Technology and Information Services		$ 985	$ 914