Summary of Impaired Loans (Cash Basis Method) (Detail) - Financial Services - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Interest income recognized:
Interest income recognized on a cash basis	$ 0.6	$ 0.6	$ 1.3	$ 1.6
Dealer | Retail
Interest income recognized:
Interest income recognized on a cash basis	0.1		0.1
Customer Retail | Fleet
Interest income recognized:
Interest income recognized on a cash basis	0.4	$ 0.6	1.0	$ 1.6
Customer Retail | Owner/Operator
Interest income recognized:
Interest income recognized on a cash basis	$ 0.1		$ 0.2