Segment Operating Results (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Net Revenues	$ 3,289,499	$ 2,263,905	$ 2,008,698
Operating Expenses	2,178,500	1,688,015	1,534,122
Other Expenses	8,561	49,457	36,865
Income Before Income from Equity Method Investments and Income Taxes	1,102,438	526,433	437,711
Income from Equity Method Investments	14,161	14,398	10,996
Pre-Tax Income	1,116,599	540,831	448,707
Identifiable Segment Assets	3,802,657	3,370,888	2,598,613
Investment Banking [Member]
Segment Reporting Information [Line Items]
Net Revenues	3,223,889	2,217,386	1,951,795
Operating Expenses	2,125,871	1,637,542	1,485,477
Other Expenses	7	49,112	33,618
Income Before Income from Equity Method Investments and Income Taxes	1,098,011	530,732	432,700
Income from Equity Method Investments	1,337	1,546	916
Pre-Tax Income	1,099,348	532,278	433,616
Identifiable Segment Assets	3,605,332	3,186,864	2,393,647
Investment Management [Member]
Segment Reporting Information [Line Items]
Net Revenues	65,610	46,519	56,903
Operating Expenses	52,629	50,473	48,645
Other Expenses	8,554	345	3,247
Income Before Income from Equity Method Investments and Income Taxes	4,427	(4,299)	5,011
Income from Equity Method Investments	12,824	12,852	10,080
Pre-Tax Income	17,251	8,553	15,091
Identifiable Segment Assets	$ 197,325	$ 184,024	$ 204,966