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Acquisition of Shoal Creek Mine - Pro Forma Financial Information (Details) - Shoal Creek $ / shares in Units, $ in Millions | 9 Months Ended
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Dec. 31, 2017 USD ($) $ / shares
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items] |
Revenue | $ | $ 1,567.7
Income from continuing operations, net of income taxes | $ | $ 251.2
Basic earnings per share from continuing operations | $ / shares | $ 1.17
Diluted earnings per share from continuing operations | $ / shares | $ 1.15

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- Definition The pro forma basic net income per share for a period as if the business combination or combinations had been completed at the beginning of a period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(2)-(3) -URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463 + Details
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