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	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Revenues:
Revenue from contracts with customers	$ 842,490	$ 768,137
Other sources of revenue:
Interest	475,632	506,828
Principal transactions	141,660	139,014
Other	9,244	3,714
Total revenues	1,469,026	1,417,693
Commissions [Member]
Revenues:
Revenue from contracts with customers	193,670	185,476
Investment Banking [Member]
Revenues:
Revenue from contracts with customers	237,942	213,949
Asset Management [Member]
Revenues:
Revenue from contracts with customers	409,541	367,476
Other [Member]
Revenues:
Revenue from contracts with customers	$ 1,337	$ 1,236