Balance Sheet Accounts - Schedule of Estimated Fair Value and Principal Amount of Outstanding Debt (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Fair Value	$ 782.1	$ 874.1
Principal Amount	615.0	628.1
Term loan
Debt Instrument [Line Items]
Fair Value	304.0	328.1
Principal Amount	315.0	328.1
2 1/4% Notes
Debt Instrument [Line Items]
Fair Value	478.1	546.0
Principal Amount	300.0	300.0
Convertible Debt \| 2 1/4% Notes
Debt Instrument [Line Items]
Principal Amount	$ 269.4	$ 263.0
Debt instrument interest rate stated percentage	2.25%

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

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
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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.

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