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Income Taxes (Tax Examinations) (Details) - USD ($) $ in Millions | Dec. 31, 2017 | Dec. 31, 2016 | Jun. 30, 2016
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Income Tax Examination [Line Items] |  |  |
Increase in deferred tax assets | $ 137.1 | $ 178.9 |
Tax Year 2012 |  |  |
Income Tax Examination [Line Items] |  |  |
Increase in deferred tax assets |  |  | $ 0.6
Increase in valuation allowance |  |  | $ 0.6

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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319 + Details
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