Revenues from Contracts with Customers (Revenues from Contracts with Customers Disaggregated by Major Business Activity and Primary Geographic Regions) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2025	Mar. 31, 2024
Disaggregation Of Revenue [Line Items]
Commissions	$ 193,670	$ 185,476
Investment banking	237,942	213,949
Revenue from contracts with customers	842,490	768,137
Capital Raising [Member]
Disaggregation Of Revenue [Line Items]
Investment banking	100,472	94,697
Advisory [Member]
Disaggregation Of Revenue [Line Items]
Investment banking	137,470	119,252
Asset Management [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	409,541	367,476
Other [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	1,337	1,236
Global Wealth Management [Member]
Disaggregation Of Revenue [Line Items]
Commissions	125,826	121,217
Investment banking	5,908	4,280
Revenue from contracts with customers	542,535	494,183
Global Wealth Management [Member] \| Capital Raising [Member]
Disaggregation Of Revenue [Line Items]
Investment banking	5,908	4,280
Global Wealth Management [Member] \| Asset Management [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	409,506	367,450
Global Wealth Management [Member] \| Other [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	1,295	1,236
Institutional Group [Member]
Disaggregation Of Revenue [Line Items]
Commissions	67,844	64,259
Investment banking	232,034	209,669
Revenue from contracts with customers	299,913	273,954
Institutional Group [Member] \| Capital Raising [Member]
Disaggregation Of Revenue [Line Items]
Investment banking	94,564	90,417
Institutional Group [Member] \| Advisory [Member]
Disaggregation Of Revenue [Line Items]
Investment banking	137,470	119,252
Institutional Group [Member] \| Asset Management [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	35	26
Other [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	42
Other [Member] \| Other [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	42
United States [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	783,079	717,633
United States [Member] \| Global Wealth Management [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	542,535	494,183
United States [Member] \| Institutional Group [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	240,502	223,450
United States [Member] \| Other [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	42
United Kingdom [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	35,564	28,185
United Kingdom [Member] \| Institutional Group [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	35,564	28,185
Other [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	6,975	10,944
Other [Member] \| Institutional Group [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	6,975	10,944
Canada [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	16,872	11,375
Canada [Member] \| Institutional Group [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	$ 16,872	$ 11,375

Amount of commission revenue from buying and selling securities on behalf of customers.

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Includes (1) underwriting revenue (the spread between the resale price received and the cost of the securities and related expenses) generated through the purchasing, distributing and reselling of new issues of securities (alternatively, could be a secondary offering of a large block of previously issued securities); and (2) fees earned for mergers, acquisitions, divestitures, restructurings, and other types of financial advisory services.

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