Summary of Impaired Loans (Cash Basis Method) (Detail) - Financial Services - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Financing Receivable, Impaired [Line Items]
Interest income recognized on a cash basis	$ 0.3	$ 0.5	$ 0.7	$ 1.0
Customer Retail | Fleet
Financing Receivable, Impaired [Line Items]
Interest income recognized on a cash basis	$ 0.3	$ 0.5	0.6	$ 1.0
Customer Retail | Owner/Operator
Financing Receivable, Impaired [Line Items]
Interest income recognized on a cash basis			$ 0.1