Crude Oil Supply and Inventory Purchase Agreement - Recurring Cash Fee Paid (Details) - Interest expense - J. Aron - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Oil and Gas, Delivery Commitment [Line Items]
Recurring cash fees paid	$ 5.2	$ 6.1
El Dorado Refinery
Oil and Gas, Delivery Commitment [Line Items]
Recurring cash fees paid	3.2	2.4
Krotz Spring Refinery
Oil and Gas, Delivery Commitment [Line Items]
Recurring cash fees paid	1.0	2.3
Big Spring refinery
Oil and Gas, Delivery Commitment [Line Items]
Recurring cash fees paid	$ 1.0	$ 1.4