Related Party Transactions (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Related Party Transaction [Line Items]
Due from related parties	$ 35,525	$ 39,659		$ 35,525		$ 39,659
Fees receivable, net of allowance	45,352	34,413		45,352		34,413
Redeemable non-controlling interests, Related Party	315,123	186,911		315,123		186,911
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds	16,705		$ (3,916)	21,002	$ (6,636)
Employees
Related Party Transaction [Line Items]
Redeemable non-controlling interests, Related Party	27,000	21,300		27,000		21,300
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds	(700)		(3,400)	$ (1,300)	(4,700)
Employee Loans | Minimum
Related Party Transaction [Line Items]
Forgivable Loans, Vesting Period				1 year
Employee Loans | Maximum
Related Party Transaction [Line Items]
Forgivable Loans, Vesting Period				3 years
Affiliated Entity
Related Party Transaction [Line Items]
Fees receivable, net of allowance	6,000	6,300		$ 6,000		6,300
Affiliated Entity | Fees Payable
Related Party Transaction [Line Items]
Fees payable to related parties	100	100		100		100
Employees
Related Party Transaction [Line Items]
Due from employees	7,200	5,500		7,200		5,500
Forgivable Loan Balances	1,200	1,200		1,200		1,200
Amortization on Forgivable Loans	100		$ 700	700	$ 2,000
Investor
Related Party Transaction [Line Items]
Due to Affiliate	300	300		300		300
Other Funds
Related Party Transaction [Line Items]
Due from related parties	15,500	20,000		15,500		$ 20,000
Starboard Value LP | Equity Method Investments
Related Party Transaction [Line Items]
Interest Income, Related Party	$ 200			$ 300
Equity Method Investment, Realized Gain (Loss) on Disposal		$ 12,800
Effective interest rate						5.00%