Leases (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) lease	Dec. 31, 2018 USD ($) retail_property	Dec. 31, 2017 USD ($)
Lessee, Lease, Description [Line Items]
Operating lease undiscounted amount	$ 9.0
Finance lease undiscounted amount	$ 1.2
Number of operating leases, not yet commenced | lease	3
Number of finance leases, not yet commenced | lease	3
Number of retail stations under capital leases | retail_property		17
Operating lease, average remaining lease term		8 years
Rent expense		$ 41.6	$ 41.2
Minimum
Lessee, Lease, Description [Line Items]
Renewal term	1 year
Capital lease, renewal term		1 year
Maximum
Lessee, Lease, Description [Line Items]
Renewal term	30 years
Capital lease, renewal term		15 years