Borrowings and Debt - Long Term Debt Excluding Consolidated Funds (Details) - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Face Amount	$ 450,000,000
Fair Value, Inputs, Level 2
Debt Instrument [Line Items]
Carrying value	545,700,000	$ 568,800,000
Fair Value	546,500,000	588,600,000
Line of Credit \| Non-recourse Seed Capital Facility \| Fair Value, Inputs, Level 2
Debt Instrument [Line Items]
Carrying value	21,700,000	35,000,000.0
Fair Value	21,700,000	35,000,000.0
Line of Credit \| Revolving credit facility \| Fair Value, Inputs, Level 2
Debt Instrument [Line Items]
Carrying value	130,000,000.0	140,000,000.0
Fair Value	130,000,000.0	140,000,000.0
Senior notes \| Senior Notes, 4.80%, due 2026
Debt Instrument [Line Items]
Face Amount	$ 275,000,000
Interest rate	4.80%
Senior notes \| Senior Notes, 4.80%, due 2026 \| Fair Value, Inputs, Level 2
Debt Instrument [Line Items]
Carrying value	$ 272,600,000	272,400,000
Fair Value	273,800,000	287,200,000
Senior notes \| Senior Notes, 5.125%, due 2031
Debt Instrument [Line Items]
Face Amount	$ 125,000,000
Interest rate	5.125%
Senior notes \| Senior Notes, 5.125%, due 2031 \| Fair Value, Inputs, Level 2
Debt Instrument [Line Items]
Carrying value	$ 121,400,000	121,400,000
Fair Value	121,000,000.0	126,400,000
Total third party borrowings \| Fair Value, Inputs, Level 2
Debt Instrument [Line Items]
Carrying value	524,000,000.0	533,800,000
Fair Value	524,800,000	553,600,000
Non-recourse Seed Capital Facility \| Fair Value, Inputs, Level 2
Debt Instrument [Line Items]
Carrying value	21,700,000	35,000,000.0
Fair Value	$ 21,700,000	$ 35,000,000.0

Face (par) amount of debt instrument at time of issuance.

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

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