Commitments and Contingencies - Additional Information (Detail) $ in Millions		3 Months Ended		9 Months Ended
	Mar. 06, 2015 claimant class_action	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) claimant claim operator	Sep. 30, 2014 USD ($)
Loss Contingencies [Line Items]
Operating leases, future minimum payments due		$ 1,739.4		$ 1,739.4
Operating leases, future minimum payments due, next twelve months		420.0		420.0
Operating leases, future minimum payments, due in two years		325.9		325.9
Operating leases, future minimum payments, due in three years		266.8		266.8
Operating leases, future minimum payments, due in four years		205.0		205.0
Operating leases, future minimum payments, due thereafter		521.7		521.7
Operating leases, rent expense		$ 200.0	$ 25.1	$ 295.9	$ 48.9
Pacer International
Loss Contingencies [Line Items]
Number of owner-operators | operator				153
Number of claims heard by court | claimant	200			7
Amount claimed				$ 2.0
Number of class actions related to remaining claimants | class_action	3
Maximum | Pacer International
Loss Contingencies [Line Items]
Number of claims heard by court | claim				600