Segment Reporting Information by Segment (Parenthetical) (Detail) € in Millions, $ in Millions	3 Months Ended	6 Months Ended	9 Months Ended
Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2016 EUR (€)	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)
Truck, Parts and Other
Segment Reporting Information [Line Items]
European Commission charge	$ 0.0	$ 0.0	$ 833.0	€ 752.7	$ 833.0	$ 0.0

Amount of other expense that is infrequent in occurrence or unusual in nature.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 20
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=64828382&loc=d3e15138-107781

Name:	us-gaap_OtherNonrecurringExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration