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Income Taxes (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Income Tax Examination [Line Items] |  |  |  |
Federal corporate tax rate |  | 35.00% | 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 |  | (1.6) | $ (1.1) |
Accrued interest expense |  | 0.2 | 0.2 |
Unrecognized tax benefits that would impact our effective tax rate |  | 2.3 | 3.9 |
Interest included in total liability |  | 0.4 | $ 1.1 |
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 |  |
Statutory federal income tax rate [Domain] |  |  |  |
Income Tax Examination [Line Items] |  |  |  |
Federal corporate tax rate | 21.00% |  |  |

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- Definition 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. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=65882285&loc=d3e32718-109319 + Details
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