Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.F)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479830/718-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Share-Based Compensation - Schedule of Compensation Expense, Unrecognized Compensation Costs, and Unrecognized Compensation Cost is Expected to be Recognized (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Total equity awards \| Selling, General and Administrative Expenses
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Compensation expense	$ 1.1	$ 1.1	$ 4.0	$ 4.0
RSUs
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Unrecognized Compensation Cost	1.4		$ 1.4
Weighted Average Remaining Recognition Period			2 years
RSUs \| Selling, General and Administrative Expenses
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Compensation expense	0.3	0.8	$ 2.1	2.2
PSUs
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Unrecognized Compensation Cost	1.3		$ 1.3
Weighted Average Remaining Recognition Period			1 year 10 months 24 days
PSUs \| Selling, General and Administrative Expenses
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Compensation expense	0.8	0.3	$ 1.9	1.8
Total liability awards \| Selling, General and Administrative Expenses
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Compensation expense	1.3	1.5	3.5	4.2
Cash RSUs
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Unrecognized Compensation Cost	1.5		$ 1.5
Weighted Average Remaining Recognition Period			1 year 8 months 12 days
Cash RSUs \| Selling, General and Administrative Expenses
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Compensation expense	0.2	0.9	$ 1.0	1.9
Cash incentive award \| Suncoke LTCIP
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Unrecognized Compensation Cost	2.4		$ 2.4
Weighted Average Remaining Recognition Period			1 year 10 months 24 days
Cash incentive award \| Selling, General and Administrative Expenses \| Suncoke LTCIP
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Compensation expense	$ 1.1	$ 0.6	$ 2.5	$ 2.3