Revenues from Contracts with Customers (Schedule of Total Revenues Broken Out by Revenues from Contracts with Customers and Other Sources of Revenues) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues:
Revenue from contracts with customers	$ 3,615,636	$ 2,678,888
Other sources of revenue:
Interest	548,400	523,832	$ 724,882
Principal transactions	581,164	588,303	404,751
Other Income	37,886	26,816
Total revenues	4,783,086	3,817,839	3,514,961
Commissions [Member]
Revenues:
Revenue from contracts with customers	809,500	760,627	667,494
Investment Banking [Member]
Revenues:
Revenue from contracts with customers	1,565,381	952,308	$ 817,421
Asset Management [Member]
Revenues:
Revenue from contracts with customers	1,206,516	917,424
Other [Member]
Revenues:
Revenue from contracts with customers	$ 34,239	$ 48,529