Related Party Transactions (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Fees receivable, net of allowance	$ 45,883				$ 34,413				$ 45,883	$ 34,413
Reimbursable to affiliated funds									200		$ 100
Due from related parties	39,629				39,659				39,629	39,659
Redeemable non-controlling interests, Related Party	379,205				186,911				379,205	186,911
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds	(9,406)	$ (18,478)	$ 16,705	$ 4,297	(4,266)	$ (4,344)	$ (3,916)	$ (2,720)	(6,882)	(15,246)	(15,564)
Employees
Related Party Transaction [Line Items]
Redeemable non-controlling interests, Related Party	32,900				21,300				32,900	21,300
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds									$ (5,700)	(10,400)	(10,600)
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	12,600				6,300				$ 12,600	6,300
Affiliated Entity | Fees Payable
Related Party Transaction [Line Items]
Fees payable to related parties	300				100				300	100
Employees
Related Party Transaction [Line Items]
Due from employees	9,200				5,500				9,200	5,500
Forgivable Loan Balances	3,300				1,200				3,300	1,200
Amortization on Forgivable Loans									1,200	3,200	$ 4,400
Investor
Related Party Transaction [Line Items]
Due to Affiliate	700				300				700	300
Other Funds
Related Party Transaction [Line Items]
Due from related parties	11,800				19,700				$ 11,800	$ 19,700
Starboard Value LP | Equity Method Investments
Related Party Transaction [Line Items]
Effective interest rate									5.00%	5.00%
Interest Income, Related Party	600
Due from related parties	$ 18,700				$ 14,400				$ 18,700	$ 14,400