Segments and Related Information - Schedule of Product Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Major product category sales
Sales	$ 1,078.0	$ 1,100.4	$ 3,098.5	$ 3,239.9
Product Concentration Risk | Sales
Major product category sales
Sales	$ 1,078.0	$ 1,100.4	$ 3,098.5	$ 3,239.9
Concentration risk, percentage	100.00%	100.00%	100.00%	100.00%
Product Concentration Risk | Specialty Products and Solutions | Sales
Major product category sales
Sales	$ 679.1	$ 714.0	$ 1,957.1	$ 2,141.8
Concentration risk, percentage	63.00%	64.90%	63.10%	66.10%
Product Concentration Risk | Montana/Renewables | Sales
Major product category sales
Sales	$ 319.2	$ 306.1	$ 898.9	$ 842.0
Concentration risk, percentage	29.60%	27.80%	29.10%	26.00%
Product Concentration Risk | Performance Brands | Sales
Major product category sales
Sales	$ 79.7	$ 80.3	$ 242.5	$ 256.1
Concentration risk, percentage	7.40%	7.30%	7.80%	7.90%
Lubricating oils | Product Concentration Risk | Specialty Products and Solutions | Sales
Major product category sales
Sales	$ 183.5	$ 192.5	$ 576.0	$ 598.1
Concentration risk, percentage	17.00%	17.50%	18.60%	18.50%
Solvents | Product Concentration Risk | Specialty Products and Solutions | Sales
Major product category sales
Sales	$ 97.7	$ 106.1	$ 303.9	$ 318.0
Concentration risk, percentage	9.10%	9.60%	9.80%	9.80%
Waxes | Product Concentration Risk | Specialty Products and Solutions | Sales
Major product category sales
Sales	$ 37.0	$ 38.8	$ 115.4	$ 117.9
Concentration risk, percentage	3.40%	3.50%	3.70%	3.60%
Fuels, asphalt and other by-products | Product Concentration Risk | Specialty Products and Solutions | Sales
Major product category sales
Sales	$ 360.9	$ 376.6	$ 961.8	$ 1,107.8
Concentration risk, percentage	33.50%	34.30%	31.00%	34.20%
Gasoline | Product Concentration Risk | Montana/Renewables | Sales
Major product category sales
Sales	$ 35.8	$ 40.8	$ 101.8	$ 110.0
Concentration risk, percentage	3.30%	3.70%	3.30%	3.40%
Diesel | Product Concentration Risk | Montana/Renewables | Sales
Major product category sales
Sales	$ 29.6	$ 31.0	$ 79.4	$ 87.9
Concentration risk, percentage	2.70%	2.80%	2.60%	2.70%
Jet fuel | Product Concentration Risk | Montana/Renewables | Sales
Major product category sales
Sales	$ 6.5	$ 5.3	$ 15.4	$ 14.8
Concentration risk, percentage	0.60%	0.50%	0.50%	0.50%
Asphalt, heavy fuel oils and other | Product Concentration Risk | Montana/Renewables | Sales
Major product category sales
Sales	$ 42.9	$ 51.3	$ 123.5	$ 118.5
Concentration risk, percentage	4.00%	4.70%	4.00%	3.70%
Renewable fuels | Product Concentration Risk | Montana/Renewables | Sales
Major product category sales
Sales	$ 204.4	$ 177.7	$ 578.8	$ 510.8
Concentration risk, percentage	19.00%	16.10%	18.70%	15.70%