Revenue and Accounts Receivable - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Investment Banking [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer	$ 566,121	$ 809,477	$ 1,920,135	$ 2,113,765
Investment Banking [Member] | Advisory Fees [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer	488,224	708,333	1,689,033	1,781,065
Investment Banking [Member] | Underwriting Fees [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer	28,697	54,381	78,519	181,686
Investment Banking [Member] | Commissions and Related Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer	49,200	46,763	152,583	151,014
Investment Management [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer	15,641	16,960	48,724	48,092
Investment Management [Member] | Wealth Management [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer	$ 15,641	$ 16,960	$ 48,724	$ 48,092