Consolidated Company-Sponsored Investment Funds - Offsetting of Derivative Assets and Liabilities (Details) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Derivative Asset [Abstract]
Cash Collateral Received	$ (2,700,000)	$ (400,000)
Derivative Liability [Abstract]
Cash Collateral Pledged	(3,400,000)	(6,400,000)
VIEs
Derivative Asset [Abstract]
Gross Amounts of Recognized Assets	4,481,000	3,224,000
Gross Amounts Offset in the Statement of Financial Condition	0	0
Net Amounts of Assets Presented in the Statement of Financial Condition	4,481,000	3,224,000
Financial Instruments Collateral	0	0
Cash Collateral Received	(1,005,000)	(513,000)
Net Amount	3,476,000	2,711,000
Derivative Liability [Abstract]
Gross Amounts of Recognized Liabilities	21,667,000	6,893,000
Gross Amounts Offset in the Statement of Financial Condition	0	0
Net Amounts of Liabilities Presented in the Statement of Financial Condition	21,667,000	6,893,000
Financial Instruments Collateral	0	0
Cash Collateral Pledged	(1,075,000)	(4,201,000)
Net Amount	20,592,000	2,692,000
VOEs
Derivative Asset [Abstract]
Gross Amounts of Recognized Assets		464,000
Gross Amounts Offset in the Statement of Financial Condition		0
Net Amounts of Assets Presented in the Statement of Financial Condition		464,000
Financial Instruments Collateral		0
Cash Collateral Received	0	0
Net Amount		464,000
Derivative Liability [Abstract]
Gross Amounts of Recognized Liabilities		664,000
Gross Amounts Offset in the Statement of Financial Condition		0
Net Amounts of Liabilities Presented in the Statement of Financial Condition		664,000
Financial Instruments Collateral		0
Cash Collateral Pledged	$ 0	(138,000)
Net Amount		$ 526,000