Share-Based Compensation (Details Textual) $ / shares in Units, $ in Millions	9 Months Ended
Sep. 30, 2020 USD ($) annual_installment $ / shares shares	Sep. 30, 2019 USD ($)
Director
Deferred Compensation Arrangement With Individual Share Based Payments [Line Items]
Compensation expense \| $	$ 0.1	$ 0.2
Restricted stock units
Deferred Compensation Arrangement With Individual Share Based Payments [Line Items]
Restricted stock (in shares)	304,332
Fair value grant (in dollars per share) \| $ / shares	$ 6.04
Number of annual installment in which stock option exercisable (in installments) \| annual_installment	3
Period from grant date for annual installment (in years)	1 year
PSUs \| Minimum
Deferred Compensation Arrangement With Individual Share Based Payments [Line Items]
Percent of original award granted	0.00%
PSUs \| Maximum
Deferred Compensation Arrangement With Individual Share Based Payments [Line Items]
Percent of original award granted	250.00%
Stock options
Deferred Compensation Arrangement With Individual Share Based Payments [Line Items]
Options granted (in shares)	0
Restricted Stock Units Settled in Cash
Deferred Compensation Arrangement With Individual Share Based Payments [Line Items]
Restricted stock (in shares)	263,998
Fair value grant (in dollars per share) \| $ / shares	$ 6.04
Number of annual installment in which stock option exercisable (in installments) \| annual_installment	3
Period from grant date for annual installment (in years)	1 year
Cash incentive award \| Suncoke LTCIP
Deferred Compensation Arrangement With Individual Share Based Payments [Line Items]
Grant date fair value of award \| $	$ 2.0
Percent of award allocation	50.00%
Measurement period	3 years

Number of annual Installment in which stock option exercisable.

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Share-based Compensation Arrangement by Share-base Payment Award, Terms of Award, Percentage Adjustment of Award Determined by Pre-Tax Return on Capital

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Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Measurement Period

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Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Fair Value

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Share-based Compensation Arrangement by Share-based Payment Award, Percent of Award Allocation

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

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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Net number of share options (or share units) granted during the period.

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