Pre- and Post-Modification Recorded Investment Balances for Finance Receivables Modified by Portfolio Class (Detail) (Financial Services, USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Investment	$ 26.7	$ 13.8
Post-Modification Recorded Investment	26.4	13.6
Customer Retail | Fleet
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Investment	24.4	11.4
Post-Modification Recorded Investment	24.1	11.2
Customer Retail | Owner/Operator
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Investment	2.3	2.4
Post-Modification Recorded Investment	$ 2.3	$ 2.4