Summary of Significant Accounting Policies - Marketable Software (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Decrease to amortization expense	$ (9.5)	$ (14.7)
Increase to operating income	42.9	101.8
Decrease to consolidated net loss	$ (19.4)	$ 40.6
Decrease to diluted loss per share (in dollars per share)	$ (0.38)	$ 0.62
Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Decrease to amortization expense	$ 4.4
Decrease to consolidated net loss	$ 4.4
Decrease to diluted loss per share (in dollars per share)	$ 0.08
Marketable Software
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Typical renewal period (on average)	5 years
Finite-lived intangible asset in process	$ 90.1
Finite-lived intangible asset remaining	$ 80.6
Weighted-average remaining life	3 years 11 days
Enterprise Software
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated revenue-producing lives of enterprise software	5 years
Enterprise software product as percentage of total marketable software	64.00%
Enterprise Software \| Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated revenue-producing lives of enterprise software	3 years
Remaining Products Classified as Marketable Software
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated revenue-producing lives of enterprise software	3 years

Finite-Lived Intangible Assets, Percentage of Total Computer Software Intangible Asset

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Finite-Lived Intangible Assets, Typical Renewal Period

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Remaining amortization period of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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.

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The net result for the period of deducting operating expenses from operating revenues.

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