Accounting Policies - Additional Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) Segment	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Accounting Policies [Line items]
Number of reportable segments | Segment	1
Restricted amounts held in escrow-current	$ 4.1	$ 38.7
Percentage of workforce covered by collective bargaining agreements	80.00%
Allowance for doubtful accounts	$ 13.2	13.8
Rerate reserve as a reduction to accounts receivable	14.1	12.6
Deferred revenue	$ 41.3	$ 31.9
Risk-free rate for maturities of workers' compensation claims	0.40%	0.50%	2.00%
Risk-free rate for property damage and liability claims	0.20%	0.50%	2.10%
Depreciation	$ 137.1	$ 133.0	$ 150.5
Cargo Claims And Other Insurance Related Amounts
Accounting Policies [Line items]
Undiscounted amount	$ 17.1	$ 11.1