Segment Operating Results (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Segment Reporting Information [Line Items]
Net Revenues	$ 630,917	$ 687,865	$ 1,353,771	$ 1,350,175
Operating Expenses	484,203	480,852	997,693	948,947
Other Expenses	532	0	532	7
Income Before Income from Equity Method Investments and Income Taxes	146,182	207,013	355,546	401,221
Income from Equity Method Investments	2,274	3,394	4,786	6,418
Pre-Tax Income	148,456	210,407	360,332	407,639
Identifiable Segment Assets	3,011,488	2,947,448	3,011,488	2,947,448	$ 3,802,657
Investment Banking [Member]
Segment Reporting Information [Line Items]
Net Revenues	615,250	670,820	1,319,551	1,318,105
Operating Expenses	470,540	468,160	971,112	924,686
Other Expenses	532	0	532	7
Income Before Income from Equity Method Investments and Income Taxes	144,178	202,660	347,907	393,412
Income from Equity Method Investments	164	549	538	718
Pre-Tax Income	144,342	203,209	348,445	394,130
Identifiable Segment Assets	2,859,302	2,775,859	2,859,302	2,775,859
Investment Management [Member]
Segment Reporting Information [Line Items]
Net Revenues	15,667	17,045	34,220	32,070
Operating Expenses	13,663	12,692	26,581	24,261
Other Expenses	0	0	0	0
Income Before Income from Equity Method Investments and Income Taxes	2,004	4,353	7,639	7,809
Income from Equity Method Investments	2,110	2,845	4,248	5,700
Pre-Tax Income	4,114	7,198	11,887	13,509
Identifiable Segment Assets	$ 152,186	$ 171,589	$ 152,186	$ 171,589