Estimated Value of Returned Goods Assets and Related Return Liabilities (Detail) - Truck, Parts and Other - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Trucks
Entity Wide Information Revenue From External Customer [Line Items]
Other current assets	$ 109.9	$ 116.7
Accounts payable, accrued expenses and other	114.5	121.7
Other noncurrent assets, net	143.6	135.9
Other liabilities	150.8	144.7
Assets	253.5	252.6
Liabilities	265.3	266.4
Parts Subsegment
Entity Wide Information Revenue From External Customer [Line Items]
Other current assets	100.8	101.7
Accounts payable, accrued expenses and other	240.3	244.4
Assets	100.8	101.7
Liabilities	$ 240.3	$ 244.4