Investments of Operating Entities and Consolidated Funds - Equity Method Investments - (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Schedule of Equity Method Investments [Line Items]
Other investments	$ 157,279	$ 141,647
Net Gains (Losses) on Securities, Derivatives and Other Investments
Schedule of Equity Method Investments [Line Items]
Income (Loss) from Equity Method Investments	14,400	3,400	$ 49,100
Equity Method Investments
Schedule of Equity Method Investments [Line Items]
Other investments	36,991	$ 27,067
Starboard Value LP | Equity Method Investments
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Realized Gain (Loss) on Disposal	$ 9,600
Effective interest rate	5.00%	5.00%
Other investments	$ 12,501	$ 15,769
Surf House Ocean Views Holdings, LLC | Equity Method Investments
Schedule of Equity Method Investments [Line Items]
Other investments	13,522	0
RCG Longview Debt Fund V Partners, LLC | Equity Method Investments
Schedule of Equity Method Investments [Line Items]
Other investments	7,256	4,655
Urban American Real Estate Fund II, LLC | Equity Method Investments
Schedule of Equity Method Investments [Line Items]
Other investments	0	1,211
Healthcare Royalty GP II, LLC | Equity Method Investments
Schedule of Equity Method Investments [Line Items]
Other investments	354	1,017
Healthcare Royalty GP, LLC | Equity Method Investments
Schedule of Equity Method Investments [Line Items]
Other investments	583	989
RCG Longview Management, LLC | Equity Method Investments
Schedule of Equity Method Investments [Line Items]
Other investments	656	656
RCG Urban American Management, LLC | Equity Method Investments
Schedule of Equity Method Investments [Line Items]
Other investments	0	379
RCG Longview Debt Fund IV Management, LLC | Equity Method Investments
Schedule of Equity Method Investments [Line Items]
Other investments	331	331
RCG Kennedy House, LLC | Equity Method Investments
Schedule of Equity Method Investments [Line Items]
Other investments	183	304
Healthcare Royalty GP III, LLC | Equity Method Investments
Schedule of Equity Method Investments [Line Items]
Other investments	208	88
RCG Longview Equity Management, LLC | Equity Method Investments
Schedule of Equity Method Investments [Line Items]
Other investments	114	114
RCG Urban American, LLC | Equity Method Investments
Schedule of Equity Method Investments [Line Items]
Other investments	0	120
Healthcare Overflow Fund GP, LLC [Member] | Equity Method Investments
Schedule of Equity Method Investments [Line Items]
Other investments	68	0
Equity Method Investee, Other | Equity Method Investments
Schedule of Equity Method Investments [Line Items]
Other investments	$ 1,215	1,434
Minimum
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	20.00%
Maximum
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	57.00%
Clawback Obligation [Member]
Schedule of Equity Method Investments [Line Items]
Other Commitment	$ 6,200	6,200
Clawback Obligation [Member] | RCG Longview Partners II, LLC
Schedule of Equity Method Investments [Line Items]
Other Commitment	$ 6,200	6,200
Operating Companies [Member] | Equity Method Investee, Exceeded Threshold for Income Test [Member]
Schedule of Equity Method Investments [Line Items]
number of investments	1
Equity Method Investment, Summarized Financial Information, Cash	$ 1,176	213
Equity Method Investment, Summarized Financial Information, Performance Fee Receivable	10,146	16,839
Equity Method Investment, Summarized Financial Information, Investments in Portfolio Funds	2,490	3,425
Equity Method Investment, Summarized Financial Information, Total Liabilities	5,604	0
Equity Method Investment, Summarized Financial Information, Equity Excluding Noncontrolling Interests	8,208	20,477
Equity Method Investment, Summarized Financial Information, Revenue	24,008	(19,246)	90,905
Equity Method Investment, Summarized Financial Information, Expenses	0	0	0
Equity Method Investment, Summarized Financial Information, Gain (Loss) on Investments	301	(221)	734
Equity Method Investment, Summarized Financial Information, Net Income (Loss)	24,309	(19,467)	91,639
Equity method investment, summarized financial information,in aggregate [Member] | Operating Companies [Member] | Equity Method Investee, Exceeded Threshold for Income Test [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investment, summarized financial information total assets	88,965	96,529
Equity Method Investment, Summarized Financial Information, Total Liabilities	22,504	10,669
Equity Method Investment, Summarized Financial Information, Equity Excluding Noncontrolling Interests	66,461	85,860
Equity Method Investment, Summarized Financial Information, Revenue	90,337	38,571	139,360
Equity Method Investment, Summarized Financial Information, Expenses	(34,490)	(20,658)	(20,044)
Equity Method Investment, Summarized Financial Information, Gain (Loss) on Investments	(6,305)	9,715	12,342
Equity Method Investment, Summarized Financial Information, Net Income (Loss)	$ 49,542	$ 27,628	$ 131,658