Fair Value Measurements for Operating Entities and Consolidated Funds Fair Value Inputs, Unobservable Inputs, Quantitative Information (Details) (USD $) In Thousands, unless otherwise specified			9 Months Ended								9 Months Ended					9 Months Ended								9 Months Ended				9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014 Options	Sep. 30, 2014 Options Level 3 Market Approach Valuation Technique Minimum	Sep. 30, 2014 Options Level 3 Market Approach Valuation Technique Maximum	Sep. 30, 2014 Contingent liability payable	Jun. 30, 2014 Contingent liability payable	Dec. 31, 2013 Contingent liability payable	Sep. 30, 2013 Contingent liability payable	Jun. 30, 2013 Contingent liability payable	Dec. 31, 2012 Contingent liability payable	Sep. 30, 2014 Contingent liability payable Level 3 Income Approach and Market Approach Valuation Techniques Minimum	Sep. 30, 2014 Contingent liability payable Level 3 Income Approach and Market Approach Valuation Techniques Maximum	Sep. 30, 2014 Other Investments [Member]		Sep. 30, 2014 Options	Sep. 30, 2014 Options Level 3 Market Approach Valuation Technique Minimum	Sep. 30, 2014 Options Level 3 Market Approach Valuation Technique Maximum	Sep. 30, 2014 Warrants and Rights	Jun. 30, 2014 Warrants and Rights	Dec. 31, 2013 Warrants and Rights	Sep. 30, 2013 Warrants and Rights	Jun. 30, 2013 Warrants and Rights	Dec. 31, 2012 Warrants and Rights	Sep. 30, 2014 Warrants and Rights Level 3 Market Approach Valuation Technique	Sep. 30, 2014 Warrants and Rights Level 3 Market Approach Valuation Technique Minimum	Sep. 30, 2014 Warrants and Rights Level 3 Market Approach Valuation Technique Maximum	Sep. 30, 2014 Common and Preferred Stock	Sep. 30, 2014 Common and Preferred Stock Level 3 Income Approach and Market Approach Valuation Techniques Minimum	Sep. 30, 2014 Common and Preferred Stock Level 3 Income Approach and Market Approach Valuation Techniques Maximum	Sep. 30, 2014 Common and Preferred Stock Level 3 Market Approach Valuation Technique
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value	$ 244,474												$ 212,757	[1]	$ 28,785			$ 2,608	$ 3,346	$ 5,805	$ 2,667	$ 2,136	$ 1,713				$ 324
DCF discount rate											6.00%	9.00%
Market multiple																												2	3
Volatility			30.00%	45.00%												30.00%	45.00%								20.00%	60.00%				45.00%
Balance Liability Value	$ 35,204	$ 28,785			$ 6,419	$ 6,783	$ 6,937	$ 7,834	$ 7,928	$ 8,116
Fair Value Assumptions, Weighted Average Volatility Rate																								39.00%
Fair Value Assumptions, Credit Spread			6.00%	7.50%												6.00%	7.50%

[1] Quantitative disclosures of unobservable inputs and assumptions are not required for investments for which NAV per share is used as a practical expedient to determine fair value, as their redemption features rather than observability of inputs cause them to be classified as a level 3 type asset within the fair value hierarchy. In addition, the fair value of the Consolidated Funds' investments are determined based on net asset value and therefore quantitative disclosures are not included in the table above. The quantitative disclosures also exclude financial instruments for which the determination of fair value is based on prices from prior transactions.