Revenues from Contracts with Customers (Revenues from Contracts with Customers Disaggregated by Major Business Activity and Primary Geographic Regions) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022
Disaggregation Of Revenue [Line Items]
Commissions	$ 673,597	$ 710,589
Investment banking	731,255	971,485
Revenue from contracts with customers	2,709,629	2,950,827
Capital Raising [Member]
Disaggregation Of Revenue [Line Items]
Investment banking	265,667	256,862
Advisory [Member]
Disaggregation Of Revenue [Line Items]
Investment banking	465,588	714,623
Asset Management [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	1,299,496	1,262,919
Other [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	5,281	5,834
Global Wealth Management [Member]
Disaggregation Of Revenue [Line Items]
Commissions	444,949	473,638
Investment banking	16,680	19,515
Revenue from contracts with customers	1,766,069	1,761,563
Global Wealth Management [Member] \| Capital Raising [Member]
Disaggregation Of Revenue [Line Items]
Investment banking	16,680	19,515
Global Wealth Management [Member] \| Asset Management [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	1,299,361	1,262,841
Global Wealth Management [Member] \| Other [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	5,079	5,569
Institutional Group [Member]
Disaggregation Of Revenue [Line Items]
Commissions	228,648	236,951
Investment banking	714,575	951,970
Revenue from contracts with customers	943,375	1,188,999
Institutional Group [Member] \| Capital Raising [Member]
Disaggregation Of Revenue [Line Items]
Investment banking	248,987	237,347
Institutional Group [Member] \| Advisory [Member]
Disaggregation Of Revenue [Line Items]
Investment banking	465,588	714,623
Institutional Group [Member] \| Asset Management [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	135	78
Institutional Group [Member] \| Other [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	17
Other [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	185	265
Other [Member] \| Other [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers		265
Other	185
United States [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	2,507,537	2,732,788
United States [Member] \| Global Wealth Management [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	1,766,069	1,761,563
United States [Member] \| Institutional Group [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	741,283	970,960
United States [Member] \| Other [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	185	265
United Kingdom [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	107,631	148,690
United Kingdom [Member] \| Institutional Group [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	107,631	148,690
Canada [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	42,263	33,718
Canada [Member] \| Institutional Group [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	42,263	33,718
Other [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	52,198	35,631
Other [Member] \| Institutional Group [Member]
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	$ 52,198	$ 35,631

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- Definition

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

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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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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Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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