Business Combinations - Assets Acquired and Liabilities & Equity Assumed (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 01, 2017
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract]
Goodwill	$ 170,153	$ 170,153
RidgeWorth
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract]
Accounts receivable			$ 20,311
Furniture, equipment and leasehold improvements			5,505
Intangible assets			275,700
Goodwill			163,365
Deferred taxes, net			6,590
Total Assets			1,476,026
Liabilities
Accrued compensation and benefits			18,263
Accounts payable and accrued liabilities			11,858
Other liabilities			2,601
Noncontrolling Interests of CIP			16,181
Total Liabilities & Noncontrolling Interests			928,944
Total Net Assets Acquired			547,082
Consolidated entity excluding consolidated investment products | RidgeWorth
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract]
Cash and cash equivalents			39,343
Investments			5,516
Other assets			3,003
Consolidated investment products | RidgeWorth
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract]
Cash and cash equivalents			38,261
Investments			899,274
Other assets			19,158
Liabilities
Notes payable of CIP			770,160
Securities purchased payable and other liabilities of CIP			$ 109,881