Segment Operating Results (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Segment Reporting Information [Line Items]
Net Revenues	$ 576,937	$ 823,555	$ 1,930,708	$ 2,173,730
Operating Expenses	446,538	569,848	1,444,231	1,518,795
Other Expenses	0	8,554	532	8,561
Income Before Income from Equity Method Investments and Income Taxes	130,399	245,153	485,945	646,374
Income from Equity Method Investments	2,027	3,681	6,813	10,099
Pre-Tax Income (Loss)	132,426	248,834	492,758	656,473
Identifiable Segment Assets	3,151,269	3,271,888	3,151,269	3,271,888	$ 3,802,657
Investment Banking [Member]
Segment Reporting Information [Line Items]
Net Revenues	560,518	806,918	1,880,069	2,125,023
Operating Expenses	433,599	556,277	1,404,711	1,480,963
Other Expenses	0	0	532	7
Income Before Income from Equity Method Investments and Income Taxes	126,919	250,641	474,826	644,053
Income from Equity Method Investments	451	564	989	1,282
Pre-Tax Income (Loss)	127,370	251,205	475,815	645,335
Identifiable Segment Assets	2,986,364	3,097,453	2,986,364	3,097,453
Investment Management [Member]
Segment Reporting Information [Line Items]
Net Revenues	16,419	16,637	50,639	48,707
Operating Expenses	12,939	13,571	39,520	37,832
Other Expenses	0	8,554	0	8,554
Income Before Income from Equity Method Investments and Income Taxes	3,480	(5,488)	11,119	2,321
Income from Equity Method Investments	1,576	3,117	5,824	8,817
Pre-Tax Income (Loss)	5,056	(2,371)	16,943	11,138
Identifiable Segment Assets	$ 164,905	$ 174,435	$ 164,905	$ 174,435