Leases - Additional Information (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019 USD ($) Location Lease	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) Location Lease	Jun. 30, 2018 USD ($)
Lessee Lease Description [Line Items]
Cash payment for lease costs	$ 19.9		$ 35.7
Operating lease not yet commenced, future lease payments	$ 123.0		$ 123.0
Minimum
Lessee Lease Description [Line Items]
Fleet operating costs period			2 years
Initial term of operating lease not yet commenced	3 years		3 years
Maximum
Lessee Lease Description [Line Items]
Fleet operating costs period			3 years
Initial term of operating lease not yet commenced	10 years		10 years
Real Estate Lease
Lessee Lease Description [Line Items]
Number of locations | Location	145		145
Number of leases commenced having initial lease term of twelve months or longer | Lease	79		79
Number of lease not yet commenced having initial lease term of twelve months or longer | Lease	8		8
Lessee, operating lease, Option to extend, description			For certain leases the Company has options to extend the lease term for periods varying from one to five years.
Lessee, operating lease, existence of option to extend			true
Lessee, operating lease, description			The Company leases real estate property at approximately 145 locations with 79 commenced leases and 8 not yet commenced leases having an initial term of 12 months or longer as of June 30, 2019. These leases are classified as operating leases. As of June 30, 2019, the remaining lease terms vary from four months to 11 years. For certain leases the Company has options to extend the lease term for periods varying from one to five years. These renewal options are not considered in the remaining lease term unless it is reasonably certain that the Company will exercise such options. For leases with an initial term of 12 months or longer, the Company has recorded a right-of-use asset and lease liability representing the fixed component of the lease payment.
Real Estate Lease | Minimum
Lessee Lease Description [Line Items]
Lessee, operating lease, term of contract			4 months
Lessee, operating lease, option to extend term			1 year
Real Estate Lease | Maximum
Lessee Lease Description [Line Items]
Lessee, operating lease, term of contract			11 years
Lessee, operating lease, option to extend term			5 years
Select Express Drive Partner Program
Lessee Lease Description [Line Items]
Sublease revenue	$ 26.7	$ 11.6	$ 44.2	$ 14.1
Select Express Drive Partner Program | Minimum
Lessee Lease Description [Line Items]
Fleet operating costs period			2 years
Select Express Drive Partner Program | Maximum
Lessee Lease Description [Line Items]
Fleet operating costs period			3 years