Commitments and Contingencies - Additional Information (Detail) € in Millions, $ in Millions			3 Months Ended					6 Months Ended
	Jul. 19, 2016 USD ($)	Jul. 19, 2016 EUR (€)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2016 EUR (€)	Mar. 31, 2016 USD ($)	Mar. 31, 2016 EUR (€)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)
Commitments and Contingencies Disclosure [Line Items]
European Commission charge				$ (109.6)				$ 0.0	$ 833.0
Truck, Parts and Other
Commitments and Contingencies Disclosure [Line Items]
European Commission charge			$ 0.0	$ (109.6)	€ (97.3)	$ 942.6	€ 850.0	$ 0.0	$ 833.0
Litigation settlement amount	$ 833.0	€ 752.7