Recorded Investment for Finance Receivables that are on Non-accrual Status (Detail) - Financial Services - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded investment of finance receivables that are on non-accrual status	$ 48.9	$ 56.5
Dealer | Wholesale
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded investment of finance receivables that are on non-accrual status	0.1	0.1
Customer Retail | Fleet
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded investment of finance receivables that are on non-accrual status	41.5	49.5
Customer Retail | Owner/Operator
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded investment of finance receivables that are on non-accrual status	$ 7.3	$ 6.9