Fair Value (Details) $ in Thousands	6 Months Ended	12 Months Ended
Jun. 30, 2016 USD ($) investment acquisition	Dec. 31, 2015 USD ($) investment
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Private equity investments measured at cost	$ 31,200	$ 32,000
Number of private equity investments measured using practical expedient \| investment	1	1
Contingent Payment Arrangements
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Number of acquisitions \| acquisition	3
Private Equity Investment Energy Fund
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair value of investments	$ 4,800	$ 6,500
Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Contingent payment arrangements	30,861	31,399
Recurring \| Contingent Payment Arrangements
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Contingent payment arrangements	$ 30,900	31,400
Weighted Average \| Contingent Payment Arrangements
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
AUM growth rate	46.00%
Revenue growth rate	43.00%
Minimum \| Contingent Payment Arrangements
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount rate	3.00%
Level 3 \| Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Contingent payment arrangements	$ 30,861	$ 31,399
Luxembourg Funds
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Number of variable interest entities consolidated \| investment	3
Luxembourg Funds \| Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Number of variable interest entities consolidated \| investment	3
Fair value of investments	$ 2,400
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 cost		$ 10,200

Percentage of assumed growth under assets management, used as an input to measure fair value.

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Number of Private Equity Investments

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Number of Private Equity Investments Measured Using Net Asset Value

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Number of Variable Interest Entities Consolidated

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Fair value of investments in certain entities that calculate net asset value per share, including, but not limited to, by unit, membership interest, or other ownership interest. Investments include, but are not limited to, investments in certain hedge funds, venture capital funds, private equity funds, real estate partnerships or funds.

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-Publisher FASB
-Name Accounting Standards Codification
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Amount of liability recognized arising from contingent consideration in a business combination.

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Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt.

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Percentage of assumed long-term growth in revenues, used as an input to measure fair value.

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Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

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The number of businesses acquired by the entity during the period.

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