Business Combination - Schedule of Finite-Lived and Indefinite-Lived Intangible Assets (Details) - RidgeWorth $ in Thousands	Jun. 01, 2017 USD ($)
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 267,000
Mutual Fund Investment Contracts
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 189,200
Weighted Average of Useful Life	16 years
Institutional and Retail Separate Account Investment Contracts
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 77,000
Weighted Average of Useful Life	10 years 4 months 24 days
Trademarks/Trade Names
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 800
Weighted Average of Useful Life	10 years