Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Examination [Line Items]
Federal corporate tax rate	21.00%	35.00%	35.00%
Tax benefit recognized due to change in U.S. corporate income tax rate		$ (110.5)
Increase (decrease) in net liability for unrecognized tax benefits	$ (0.2)	(1.6)
Accrued interest expense	0.1	0.2
Unrecognized tax benefits that would impact our effective tax rate	2.0	2.3
Interest included in total liability	0.4	$ 0.4
Significant increases or decreases for uncertain tax positions	$ 0.0
State and Foreign Tax Authorities \| Minimum
Income Tax Examination [Line Items]
Period of statute of limitations (years)	3 years
State and Foreign Tax Authorities \| Maximum
Income Tax Examination [Line Items]
Period of statute of limitations (years)	4 years

Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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The amount of the unrecognized tax benefit of a position taken for which it is reasonably possible that the total amount thereof will significantly increase or decrease within twelve months of the balance sheet date.

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Amount of interest expense accrued for an underpayment of income taxes.

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Amount of interest expense for an underpayment of income taxes.

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Amount of increase (decrease) in unrecognized tax benefits attributable to uncertain tax positions taken in tax returns.

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The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.

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Income Tax Contingency, Period of Statute of Limitations

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Amount of income tax expense (benefit) related to the January 1, 2018 change in U.S. tax rate under the Tax Reform Act.

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