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Income Taxes (Narrative) (Details) - USD ($) $ in Millions | 12 Months Ended |
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Dec. 31, 2017 | Dec. 31, 2018
Income Taxes [Line Items] |  |
Income Tax Benefit - Impact of Tax Legislation | $ 60.1 |
Equity Method Investment, Ownership Percentage |  | 50.00%

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- Definition [Line Items] for Income Taxes [Table] + References No definition available. + Details
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- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571 + Details
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