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Fair Value Measurements - Investments Measured at Net Asset Value as Practical Expedient (Details) - USD ($)
$ in Millions

9 Months Ended

Sep. 30, 2018

Dec. 31, 2017

NAV of investments at fair value

Life of funds (in years)

15 years

Other Investments

NAV of investments at fair value

Unfunded Commitments

^[1]

$ 130.4

$ 98.8

Other Investments | Fair Value Measured at NAV

NAV of investments at fair value

Fair Value

^[1]

192.8

165.0

Other Investments | Controlling Interest

NAV of investments at fair value

Fair Value

115.0

80.1

Private Equity Funds

NAV of investments at fair value

Unfunded Commitments

^[2]

130.4

98.8

Private Equity Funds | Fair Value Measured at NAV

NAV of investments at fair value

Fair Value

^[2]

185.4

156.1

Other Funds

NAV of investments at fair value

Unfunded Commitments

^[3]

0.0

0.0

Other Funds | Fair Value Measured at NAV

NAV of investments at fair value

Fair Value

^[3]

$ 7.4

$ 8.9

[1]	Fair value attributable to the controlling interest was $80.1 million and $115.0 million as of December 31, 2017 and September 30, 2018, respectively.
[2]	The Company uses NAV as a practical expedient one quarter in arrears (adjusted for current period calls and distributions) to determine the fair value. These funds primarily invest in a broad range of private equity funds, as well as making direct investments. Distributions will be received as the underlying assets are liquidated over the life of the funds, which is generally up to 15 years
[3]	These are multi-disciplinary funds that invest across various asset classes and strategies, including long/short equity, credit and real estate. Investments are generally redeemable on a daily, monthly or quarterly basis.

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-Publisher FASB
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