TDRs Modified During Previous Twelve Months that Subsequently Defaulted (Detail) - Financial Services - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Modifications [Line Items]
Recorded Investment, subsequently defaulted	$ 0	$ 4,900,000
Customer Retail | Fleet
Financing Receivable, Modifications [Line Items]
Recorded Investment, subsequently defaulted		4,700,000
Customer Retail | Owner/Operator
Financing Receivable, Modifications [Line Items]
Recorded Investment, subsequently defaulted		$ 200,000