Segments and Related Information (Product Information) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Major product category sales
Sales	$ 774.8	$ 929.6	$ 896.9	$ 851.3	$ 848.0	$ 953.5	$ 945.5	$ 750.5	$ 3,452.6	$ 3,497.5	$ 3,763.8
Product Concentration Risk
Major product category sales
Sales									$ 3,452.6	$ 3,497.5	$ 3,763.8
Concentration Risk, Percentage									100.00%	100.00%	100.00%
Product Concentration Risk | Specialty Product
Major product category sales
Sales									$ 1,354.1	$ 1,382.4	$ 1,300.4
Concentration Risk, Percentage									39.20%	39.50%	34.50%
Product Concentration Risk | Fuel Product
Major product category sales
Sales									$ 2,098.5	$ 2,115.1	$ 2,463.4
Concentration Risk, Percentage									60.80%	60.50%	65.50%
Lubricating oils | Product Concentration Risk | Specialty Product
Major product category sales
Sales									$ 593.1	$ 600.1	$ 584.2
Concentration Risk, Percentage									17.20%	17.20%	15.50%
Solvents | Product Concentration Risk | Specialty Product
Major product category sales
Sales									$ 325.9	$ 331.9	$ 274.4
Concentration Risk, Percentage									9.40%	9.50%	7.30%
Waxes | Product Concentration Risk | Specialty Product
Major product category sales
Sales									$ 119.3	$ 117.0	$ 117.2
Concentration Risk, Percentage									3.40%	3.30%	3.10%
Packaged and synthetic specialty products
Major product category sales
Sales									$ 230.9	$ 256.8	$ 260.7
Packaged and synthetic specialty products | Product Concentration Risk | Specialty Product
Major product category sales
Sales									$ 230.8	$ 256.8	$ 260.7
Concentration Risk, Percentage									6.70%	7.30%	6.90%
Other
Major product category sales
Sales									$ 1,123.2	$ 1,125.6	$ 1,039.7
Other | Product Concentration Risk | Specialty Product
Major product category sales
Sales									$ 85.0	$ 76.6	$ 63.9
Concentration Risk, Percentage									2.50%	2.20%	1.70%
Gasoline | Product Concentration Risk | Fuel Product
Major product category sales
Sales									$ 679.6	$ 683.1	$ 948.5
Concentration Risk, Percentage									19.70%	19.50%	25.20%
Diesel | Product Concentration Risk | Fuel Product
Major product category sales
Sales									$ 859.1	$ 910.0	$ 877.9
Concentration Risk, Percentage									24.90%	26.00%	23.40%
Jet fuel | Product Concentration Risk | Fuel Product
Major product category sales
Sales									$ 134.6	$ 100.1	$ 135.0
Concentration Risk, Percentage									3.90%	2.90%	3.60%
Asphalt, heavy fuel oils and other | Product Concentration Risk | Fuel Product
Major product category sales
Sales									$ 425.2	$ 421.9	$ 502.0
Concentration Risk, Percentage									12.30%	12.10%	13.30%