LONG-TERM DEBT AND FINANCING ARRANGEMENTS (Financing arrangements - Notes payable & Capital leases) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2017	Jun. 30, 2017
Revenue equipment and software \| Notes payable
Financing Arrangements
Equipment financed during the period under notes payable	$ 37.9	$ 38.6

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