Fair Value Measurements for Operating Entities and Consolidated Funds - Fair Value Inputs, Unobservable Inputs, Quantitative Information (Details) $ in Thousands		Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($) times	Dec. 31, 2019 USD ($)
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Other investments		$ 274,111	$ 255,027
Quarton
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, Low		10,100	10,100
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High		25,000	35,100
Portico
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, Low		0
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High		58,000
Contingent liability payable
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Liability Value		62,223	36,718	$ 30,896
Options (held long)
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value		234	251	336
Trade Claims
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value		3,496	8,713	7,083
Warrants and Rights
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value		15,403	6,547	594
Corporate Bonds
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value		2,419	135	$ 2,421
Level 3
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value		182,501	127,461
Balance Liability Value		$ 65,642	$ 42,837
Level 3 | Contingent liability payable | Valuation Technique, Discounted Cash Flow | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		0.07	0.09
Level 3 | Contingent liability payable | Valuation Technique, Discounted Cash Flow | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		0.15	0.16
Level 3 | Contingent liability payable | Valuation Technique, Discounted Cash Flow | Weighted Average
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		0.12	0.15
Level 3 | Contingent liability payable | Discount Cash Flow and Monte Carlo Technique
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Liability Value		$ 62,223	$ 36,718
Level 3 | Contingent liability payable | Volatility | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		0.20	0.22
Level 3 | Contingent liability payable | Volatility | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		0.24	0.24
Level 3 | Contingent liability payable | Volatility | Weighted Average
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		0.22	0.22
Level 3 | Other Liabilities [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Liability Value	[1]		$ 2,204
Level 3 | Common and Preferred Stock | Discounted Cash Flow and Market Approach Valuation Techniques
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value		$ 76,491	$ 65,735
Level 3 | Common and Preferred Stock | Valuation Technique, Discounted Cash Flow | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		0.125	0.10
Level 3 | Common and Preferred Stock | Valuation Technique, Discounted Cash Flow | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		0.20	0.12
Level 3 | Common and Preferred Stock | Valuation Technique, Discounted Cash Flow | Weighted Average
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		0.13	0.11
Level 3 | Common and Preferred Stock | Valuation, Market Approach | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		6.25	6.25
Level 3 | Common and Preferred Stock | Valuation, Market Approach | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		6.75	6.75
Level 3 | Common and Preferred Stock | Valuation, Market Approach | Weighted Average
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		6.5	6.5
Level 3 | Options (held long) | Discounted Cash Flow and Market Approach Valuation Techniques
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value		$ 234	$ 251
Level 3 | Options (held long) | Valuation Technique, Discounted Cash Flow | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		0.125	0.10
Level 3 | Options (held long) | Valuation Technique, Discounted Cash Flow | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		0.135	0.12
Level 3 | Options (held long) | Valuation Technique, Discounted Cash Flow | Weighted Average
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		0.13	0.11
Level 3 | Trade Claims | Valuation Technique, Discounted Cash Flow
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value		$ 2,376	$ 3,500
Level 3 | Warrants and Rights | Discounted Cash Flow and Market Approach Valuation Techniques
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value		$ 4,483	$ 11,217
Level 3 | Warrants and Rights | Valuation Technique, Discounted Cash Flow | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		0.125	0.04
Level 3 | Warrants and Rights | Valuation Technique, Discounted Cash Flow | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		0.135	0.11
Level 3 | Warrants and Rights | Valuation Technique, Discounted Cash Flow | Weighted Average
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		0.130	0.07
Level 3 | Warrants and Rights | Valuation, Market Approach | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		0.0625	0.0625
Level 3 | Warrants and Rights | Valuation, Market Approach | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		0.0675	0.0675
Level 3 | Warrants and Rights | Valuation, Market Approach | Weighted Average
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		0.065	0.065
Level 3 | Warrants and Rights | Black Scholes Model | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		0.90
Level 3 | Warrants and Rights | Black Scholes Model | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		1
Level 3 | Warrants and Rights | Black Scholes Model | Weighted Average
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		0.95
Level 3 | Corporate Bonds | Discounted Cash Flow and Market Approach Valuation Techniques
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value			$ 12,623
Level 3 | Corporate Bonds | Valuation Technique, Discounted Cash Flow | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input			0.10
Level 3 | Corporate Bonds | Valuation Technique, Discounted Cash Flow | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input			0.12
Level 3 | Corporate Bonds | Valuation Technique, Discounted Cash Flow | Weighted Average
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input			0.11
Level 3 | Corporate Bonds | Valuation, Market Approach | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input			6.25
Level 3 | Corporate Bonds | Valuation, Market Approach | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input			6.75
Level 3 | Corporate Bonds | Valuation, Market Approach | Weighted Average
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input | times			6.5
Level 3 | Other Investments
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value	[1]	$ 98,917	$ 34,135
Level 3 | Options (held long) | Valuation, Market Approach | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		6.25	6.25
Level 3 | Options (held long) | Valuation, Market Approach | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		6.75	6.75
Level 3 | Options (held long) | Valuation, Market Approach | Weighted Average
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		6.5	6.5
Fair Value, Measurements, Recurring | Level 3 | Options (held short) | Derivative Liabilities | Valuation Technique, Option Pricing Model
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Liability Value		$ 3,419	$ 3,915
Discount rate | Level 3 | Trade Claims | Valuation Technique, Discounted Cash Flow
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		0.40	0.15
Discount rate | Level 3 | Trade Claims | Valuation Technique, Discounted Cash Flow | Weighted Average
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		0.40	0.15
Volatility | Level 3 | Options (held short) | Valuation Technique, Option Pricing Model
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		0.35	0.35
Volatility | Level 3 | Options (held short) | Valuation Technique, Option Pricing Model | Weighted Average
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Measurement Input		0.35	0.35

[1] The quantitative disclosures exclude financial instruments for which the determination of fair value is based on prices from recent transactions.