| **Income Taxes (Tables)**                   | 9 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
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| **Income Tax Disclosure [Abstract]**        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
| Reconciliation of Unrecognized Tax Benefits | A reconciliation of the beginning and ending liability for unrecognized tax benefits is as follows (in millions): Gross Unrecognized Income Tax BenefitsBalance at December 31, 2015$2.9Gross amount of increases in unrecognized tax benefits related to prior periods0.3Gross amount of decreases in unrecognized tax benefits related to prior periods(0.4)Gross amount of increases in unrecognized tax benefits related to current periods0.1Gross amount of decreases in unrecognized tax benefits related to current periods(0.1)Balance at September 30, 2016$2.8 |

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| - References
No definition available.
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| - Definition
Tabular disclosure for tax positions taken in the tax returns filed or to be filed for which it is more likely than not that the tax position will not be sustained upon examination by taxing authorities and other income tax contingencies. Includes, but is not limited to, interest and penalties, reconciliation of unrecognized tax benefits, unrecognized tax benefits that would affect the effective tax rate, tax years that remain subject to examination by tax jurisdictions, and information about positions for which it is reasonably possible that amounts unrecognized will significantly change within 12 months.
+ References
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