Stock-Based Compensation and Employee Benefit Plan - Restricted Stock Units (Additional Information) (Details) - Restricted Stock - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of RSUs grants in period	$ 219.1	$ 1.5	$ 220.4	$ 16.4
Unrecognized stock-based compensation cost	$ 238.6		$ 238.6
Expense expected to be recognized over a weighted-average period			1 year 29 days

Employee and Non-Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options

No definition available.

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- Definition

Share-based Compensation Arrangement By Share-based Payment Award, Equity Instruments Other Than Options, Grants in Period, Aggregate Fair Value

+ References

No definition available.

+ Details

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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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- Definition

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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