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		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Revenues:
Revenue from contracts with customers	$ 798,917	$ 653,827	$ 1,567,054	$ 1,352,052
Other sources of revenue:
Interest	498,152	482,770	1,004,980	934,334
Principal transactions	153,574	105,700	292,588	221,222
Other	14,618	(486)	18,332	(4,006)
Total revenues	1,465,261	1,241,811	2,882,954	2,503,602
Commissions [Member]
Revenues:
Revenue from contracts with customers	183,317	165,358	368,793	334,908
Investment Banking [Member]
Revenues:
Revenue from contracts with customers	233,281	166,825	447,230	378,704
Asset Management [Member]
Revenues:
Revenue from contracts with customers	380,757	320,264	748,233	635,833
Other [Member]
Revenues:
Revenue from contracts with customers	$ 1,562	$ 1,380	$ 2,798	$ 2,607