Leases - Additional Information (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($) Location	Mar. 31, 2018 USD ($)
Lessee Lease Description [Line Items]
Cash payment for lease costs	$ 15.8
Operating lease not yet commenced, future lease payments	$ 145.6
Minimum
Lessee Lease Description [Line Items]
Fleet operating costs period	2 years
Initial term of operating lease not yet commenced	2 years
Maximum
Lessee Lease Description [Line Items]
Fleet operating costs period	3 years
Initial term of operating lease not yet commenced	10 years
Real Estate Lease
Lessee Lease Description [Line Items]
Number of locations | Location	140
Number of locations having initial lease term of twelve months or longer | Location	80
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 primarily for office space at approximately 140 locations with approximately 80 locations having an initial term of 12 months or longer. These leases are classified as operating leases. The remaining lease terms vary from few 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, option to extend term	1 year
Real Estate Lease | Maximum
Lessee Lease Description [Line Items]
Lessee, operating lease, option to extend term	5 years
Select Express Drive Partner Program
Lessee Lease Description [Line Items]
Sublease revenue	$ 17.5	$ 2.6
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