Goodwill and Other Intangible Assets - Schedule of Changes in Carrying Amount of Goodwill (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Roll Forward]
Goodwill, Beginning Balance		$ 164.8	$ 164.0
Goodwill, Impairment Loss	$ (2.0)	(2.0)	0.0	$ 0.0
Foreign currency translation		(0.6)	0.8
Goodwill, Ending Balance	162.2	162.2	164.8	164.0
Truckload
Goodwill [Roll Forward]
Goodwill, Beginning Balance		138.2	138.2
Goodwill, Impairment Loss		0.0
Foreign currency translation		0.0	0.0
Goodwill, Ending Balance	138.2	138.2	138.2	138.2
Logistics
Goodwill [Roll Forward]
Goodwill, Beginning Balance		14.2	14.2
Goodwill, Impairment Loss		0.0
Foreign currency translation		0.0	0.0
Goodwill, Ending Balance	14.2	14.2	14.2	14.2
Other
Goodwill [Roll Forward]
Goodwill, Beginning Balance		12.4	11.6
Goodwill, Impairment Loss		(2.0)
Foreign currency translation		(0.6)	0.8
Goodwill, Ending Balance	$ 9.8	$ 9.8	$ 12.4	$ 11.6