TDRs Modified During Previous Twelve Months that Subsequently Defaulted (Detail) - Financial Services - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Modifications [Line Items]
Recorded Investment, subsequently defaulted	$ 4.9	$ 0.7
Customer Retail \| Fleet
Financing Receivable, Modifications [Line Items]
Recorded Investment, subsequently defaulted	4.7	0.3
Customer Retail \| Owner/Operator
Financing Receivable, Modifications [Line Items]
Recorded Investment, subsequently defaulted	$ 0.2	$ 0.4

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://www.xbrl.org/2003/role/presentationRef
-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

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