Description of Business and Basis of Presentation - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating income	$ 5.9	$ 20.2
Accounting Standards Update 2017-07, Year 2017 Effect
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating income	$ 0.3

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.

No definition available.

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