Schedule of Balance Sheet Information Related to Leases (Detail) $ in Millions	Sep. 30, 2019 USD ($)
OPERATING LEASES
Total right-of-use assets	$ 39.7
Total lease liabilities	40.8
FINANCE LEASES
Total right-of-use assets	1.5
Total lease liabilities	1.6
Truck, Parts and Other
OPERATING LEASES
Accounts payable, accrued expenses and other	$ 12.6
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:AccountsPayableAndOtherAccruedLiabilitiesCurrent
Other liabilities	$ 22.8
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesNoncurrent
FINANCE LEASES
Accounts payable, accrued expenses and other	$ 0.9
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:AccountsPayableAndOtherAccruedLiabilitiesCurrent
Other liabilities	$ 0.7
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesNoncurrent
Truck, Parts and Other | Other Noncurrent Assets
OPERATING LEASES
Total right-of-use assets	$ 34.4
FINANCE LEASES
Total right-of-use assets	1.5
Financial Services | Other Assets
OPERATING LEASES
Total right-of-use assets	5.3
Financial Services | Accounts Payable, Accrued Expense and Other
OPERATING LEASES
Total lease liabilities	1.5
Financial Services | Deferred Taxes and Other Liabilities
OPERATING LEASES
Total lease liabilities	$ 3.9