Long-term Compensation Plans - Schedule of Compensation Expense (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 19.3	$ 11.8	$ 7.3
Weighted average remaining vesting period (months)	13 months
Equity classified RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average remaining vesting period (months)	13 months
Continuing Operations
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 15.4	9.6	6.2
Unrecognized compensation expense for awards expected to vest	14.7
Continuing Operations \| Equity classified RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	13.9	8.3	5.4
Continuing Operations \| Liability classified RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	0.7	0.6	0.4
Continuing Operations \| Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	0.8	0.7	0.4
Discontinued Operations
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	3.9	$ 2.2	$ 1.1
Unrecognized compensation expense for awards expected to vest	$ 3.6

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Unrecognized cost of unvested share-based compensation awards.

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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.

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