TDRs Modified During Previous Twelve Months that Subsequently Defaulted (Detail) - Financial Services - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017
Financing Receivable, Modifications [Line Items]
Recorded Investment, subsequently defaulted	$ 0.8	$ 1.1
Customer Retail \| Fleet
Financing Receivable, Modifications [Line Items]
Recorded Investment, subsequently defaulted	0.8	1.0
Customer Retail \| Owner/Operator
Financing Receivable, Modifications [Line Items]
Recorded Investment, subsequently defaulted	$ 0.0	$ 0.1

Amount of investment related to financing receivables modified by troubled debt restructurings within the previous 12 months, for which there was a payment default.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953682-111524

Name:	us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration