Discontinued Operations and Divestitures (Details) $ in Millions	1 Months Ended				3 Months Ended	12 Months Ended
	Jan. 31, 2016 item	Dec. 31, 2015 USD ($) item	Sep. 30, 2015	Jun. 30, 2015 item	Mar. 31, 2015 USD ($)	Dec. 31, 2015 USD ($) entity	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Discontinued Operations and Divestitures
Number of entities newly classified as held for sale | entity						0
Balance Sheet information regarding entities accounted for as discontinued operations
Total assets		$ 13.1				$ 13.1	$ 155.6
Total liabilities		6.2				6.2	108.2
Max Cycles
Divestitures
Ownership interest sold (as a percent)			50.00%
Held-for-sale
Combined financial information regarding entities accounted for as discontinued operations
Revenues						75.8	206.8	$ 486.1
Pre-tax loss						(6.7)	(31.5)	(4.9)
Pre-tax gain on disposal						2.9	14.8	0.8
Balance Sheet information regarding entities accounted for as discontinued operations
Inventories		6.2				6.2	17.5
Other assets		6.9				6.9	138.1
Total assets		13.1				13.1	155.6
Floor plan notes payable (including non-trade)		4.3				4.3	14.6
Other liabilities		1.9				1.9	93.6
Total liabilities		$ 6.2				6.2	108.2
Disposal group reclassified as held and used
Discontinued Operation, Reclassified as Held and Used
Revenue						64.7	54.8	38.6
Pre-tax loss						$ (3.1)	$ (2.3)	$ (1.3)
Hertz car rental franchise | Disposed of by sale
Divestitures
Proceeds from sale of business					$ 17.8
Retail Automotive Franchise | Disposed of by sale
Divestitures
Number of franchises disposed | item				2
Retail Commercial Truck Used Truck Locations | Disposal group, not discontinued operations
Divestitures
Number of locations disposed of | item		1
Retail Commercial Truck Parts Locations | Disposal group, not discontinued operations
Divestitures
Number of locations disposed of | item	1