FLOOR PLAN NOTES PAYABLE (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Debt Disclosure [Abstract]
Floor plan notes payable—trade	$ 143.1	$ 120.0
Floor plan notes payable offset account	(13.7)	(11.7)
Total floor plan notes payable—trade, net	129.4	108.3
Floor plan notes payable—non-trade	691.3	732.7
Floor plan notes payable offset account	0.0	(59.2)
Total floor plan notes payable—non-trade, net	691.3	673.5
Floor plan notes payable, offsets	$ 13.7	$ 70.9