Sales and Revenues - Additional Information (Detail) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Entity Wide Information Revenue From External Customer [Line Items]
Term used to calculate historical weighted average return rate	5 years
Estimated value of trucks to be returned	$ 492,500,000		$ 473,000,000.0
Estimated sales returned liabilities	526,100,000		503,400,000
Payment to acquire commitment value	924,400,000
Payment to acquire commitment related to lease value	411,500,000
Estimated value of returned goods	59,700,000		56,300,000
Sales returns liabilities in estimated returns	136,100,000		126,300,000
Financial Services
Entity Wide Information Revenue From External Customer [Line Items]
Total operating lease income	202,800,000	$ 200,700,000
Financing receivable, recorded investment, 90 days past due and still accruing	0		$ 0
Trucks | Truck Sales
Entity Wide Information Revenue From External Customer [Line Items]
Total operating lease income	27,000,000.0	$ 41,700,000
Deferred revenue	131,400,000
Deferred revenue recognize, in 2020	57,800,000
Deferred revenue recognize, in 2021	43,600,000
Deferred revenue recognize, in 2022	19,100,000
Deferred revenue recognize, in 2023	8,800,000
Deferred revenue recognize, in 2024	2,000,000.0
Deferred revenue recognize, thereafter	$ 100,000
Minimum
Entity Wide Information Revenue From External Customer [Line Items]
Lease and guarantee periods (in years)	3 years
Minimum | Financial Services
Entity Wide Information Revenue From External Customer [Line Items]
Operating lease term	3 years
Minimum | Trucks | Financial Services
Entity Wide Information Revenue From External Customer [Line Items]
Finance leases, lease term	3 years
Maximum
Entity Wide Information Revenue From External Customer [Line Items]
Lease and guarantee periods (in years)	5 years
Warranty period	5 years
Maximum | Financial Services
Entity Wide Information Revenue From External Customer [Line Items]
Operating lease term	5 years
Maximum | Trucks | Financial Services
Entity Wide Information Revenue From External Customer [Line Items]
Finance leases, lease term	5 years