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Significant Accounting Policies Revenue and Expense Recognition (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014
Significant Accounting Policies [Abstract] |  |  |
Fuel surcharge revenue | $ 58.4 | $ 91.8 | $ 170.4

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- Definition Fuel surcharge revenue + References No definition available. + Details
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- Definition Significant Accounting Policies [Abstract] + References No definition available. + Details
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