Business Segment Information - Segment Assets (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Total assets	$ 1,679.8	$ 1,615.4
Operating Segments | Domestic Coke
Segment Reporting Information [Line Items]
Total assets	1,444.3	1,370.6
Operating Segments | Brazil Coke
Segment Reporting Information [Line Items]
Total assets	12.9	18.0
Operating Segments | Logistics
Segment Reporting Information [Line Items]
Total assets	193.7	202.9
Corporate and Other
Segment Reporting Information [Line Items]
Total assets	$ 28.9	$ 23.9