Fair Value (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2016 USD ($) investment acquisition	Dec. 31, 2015 USD ($)
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Number of private equity investments measured using practical expedient | investment	1
Private equity investments measured at fair value using net asset value	$ 31,700	$ 32,100
Private Equity Investment Venture Capital Fund
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair value of investments	6,500
Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Contingent payment arrangements	$ 31,119	31,399
Contingent Payment Arrangements
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Number of acquisition | acquisition	3
Contingent Payment Arrangements | Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Contingent payment arrangements	$ 31,100	31,400
Contingent Payment Arrangements | Weighted Average
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
AUM growth rate	46.00%
Revenue growth rate	43.00%
Contingent Payment Arrangements | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount rate	3.00%
Cost-method Investments
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Number of private equity investments | investment	1
Private equity investments measured at fair value using net asset value		10,200
Level 3 | Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Contingent payment arrangements	$ 31,119	$ 31,399
Luxembourg Funds | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Number of consolidated VIEs | investment	3
Fair value of investments	$ 5,100