Significant Accounting Policies (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Nov. 30, 2016	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jan. 01, 2020 USD ($)	Dec. 31, 2018 USD ($)
Significant Accounting Policies [Line Items]
Total Assets		$ 3,802,657	$ 3,370,888	$ 2,598,613
Total Liabilities		2,167,376	1,881,514
Retained Earnings		$ (1,635,281)	(1,489,374)	(1,126,250)		$ (1,007,939)
Investment Banking And Investment Management Receivables Collection Periods		90 days
Placement Fees Receivables Collection Period		180 days
Private Funds Capital Raising and Private Capital Receivables Collection Period		1 year
Restructuring Receivables Collection Period		90 days
Receivables Reflected in Other Assets in Excess of Period		1 year
Contract Asset Recognized For Cost of Obtaining Contract With Benefit in Excess of Period		1 year
Expense Recognized For Cost of Obtaining Contract With Amortization Less Than Period		1 year
Revision of Prior Period, Reclassification, Adjustment | Commissions and Related Revenue [Member]
Significant Accounting Policies [Line Items]
Revenue from Contract with Customer			925	592
Minimum [Member]
Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life		3 years
Maximum [Member]
Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life		7 years
Cumulative Effect, Period of Adoption, Adjustment [Member] | Accounting Standards Update 2016-13 [Member]
Significant Accounting Policies [Line Items]
Retained Earnings				1,310
Retained Earnings [Member]
Significant Accounting Policies [Line Items]
Retained Earnings		$ (1,418,382)	(798,573)	(558,269)		$ (364,882)
Retained Earnings [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member] | Accounting Standards Update 2016-13 [Member]
Significant Accounting Policies [Line Items]
Retained Earnings				$ 1,310	$ 1,310
LP Units [Member]
Significant Accounting Policies [Line Items]
Limited Partnership Units Convertible Conversion Ratio	1	1
Variable Interest Entity, Primary Beneficiary [Member]
Significant Accounting Policies [Line Items]
Total Assets		$ 446,736	377,878
Total Liabilities		$ 260,426	$ 164,779