Pre- and Post-Modification Amortized Cost Basis Balances for Finance Receivables Modified by Portfolio Class (Detail) - Financial Services - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Financing Receivable, Modifications [Line Items]
Pre-Modification, Amortized Cost Basis	$ 23.5	$ 0.8
Post-Modification, Amortized Cost Basis	23.5	0.8
Customer Retail | Fleet
Financing Receivable, Modifications [Line Items]
Pre-Modification, Amortized Cost Basis	23.4	0.6
Post-Modification, Amortized Cost Basis	23.4	0.6
Customer Retail | Owner/Operator
Financing Receivable, Modifications [Line Items]
Pre-Modification, Amortized Cost Basis	0.1	0.2
Post-Modification, Amortized Cost Basis	$ 0.1	$ 0.2