Revenues - Commercial Vehicle Distribution and Other (Details) - Commercial Vehicle Distribution and Other - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues
Total revenues	$ 124.8		$ 429.3
Penske Commercial Vehicles Australia
Revenues
Total revenues	50.4		169.6
Penske Power Systems
Revenues
Total revenues	73.3		256.8
Other
Revenues
Total revenues	$ 1.1		$ 2.9
Without Adoption of ASC 606
Revenues
Total revenues		$ 139.4		$ 366.6
Without Adoption of ASC 606 | Penske Commercial Vehicles Australia
Revenues
Total revenues		70.7		191.6
Without Adoption of ASC 606 | Penske Power Systems
Revenues
Total revenues		67.6		171.8
Without Adoption of ASC 606 | Other
Revenues
Total revenues		$ 1.1		$ 3.2