Consolidated Company-Sponsored Investment Funds - Offsetting of Derivative Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Derivative Asset [Abstract]
Cash Collateral Received	$ (800)	$ (300)
VIEs
Derivative Asset [Abstract]
Gross Amounts of Recognized Assets	1,332	4,833
Gross Amounts Offset in the Statement of Financial Condition	0	0
Net Amounts of Assets Presented in the Statement of Financial Condition	1,332	4,833
Financial Instruments	0	0
Cash Collateral Received	(270)	(1,631)
Net Amount	1,062	3,202
Derivative Liability [Abstract]
Gross Amounts of Recognized Liabilities	4,309	4,559
Gross Amounts Offset in the Statement of Financial Condition	0	0
Net Amounts of Liabilities Presented in the Statement of Financial Condition	4,309	4,559
Financial Instruments	0	0
Cash Collateral Pledged	(3,800)	(3,155)
Net Amount	509	1,404
VOEs
Derivative Asset [Abstract]
Gross Amounts of Recognized Assets	698	4,339
Gross Amounts Offset in the Statement of Financial Condition	0	0
Net Amounts of Assets Presented in the Statement of Financial Condition	698	4,339
Financial Instruments	0	0
Cash Collateral Received	(698)	(534)
Net Amount	0	3,805
Derivative Liability [Abstract]
Gross Amounts of Recognized Liabilities	1,746	5,083
Gross Amounts Offset in the Statement of Financial Condition	0	0
Net Amounts of Liabilities Presented in the Statement of Financial Condition	1,746	5,083
Financial Instruments	0	0
Cash Collateral Pledged	(1,746)	(1,201)
Net Amount	0	$ 3,882
Variable Interest Entity, Not Primary Beneficiary
Derivative [Line Items]
Net Assets	$ 63,500,000