Share-Based Compensation (Details Textual) $ / shares in Units, $ in Millions	9 Months Ended
Sep. 30, 2019 USD ($) annual_installment $ / shares shares	Sep. 30, 2018 USD ($)
Director
Deferred Compensation Arrangement With Individual Share Based Payments [Line Items]
Compensation expense \| $	$ 0.2	$ 0.3
Stock options \| Suncoke LTPEP
Deferred Compensation Arrangement With Individual Share Based Payments [Line Items]
Number of annual installment in which stock option exercisable (in installments)	3
Period from grant date for annual installment (in years)	1 year
Stock options, time until expiration (in years)	10 years
Restricted stock units
Deferred Compensation Arrangement With Individual Share Based Payments [Line Items]
Number of annual installment in which stock option exercisable (in installments)	3
Period from grant date for annual installment (in years)	1 year
Restricted stock (in shares) \| shares	136,425
Fair value grant (in dollars per share) \| $ / shares	$ 9.87
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%
Restricted Stock Units Settled in Cash
Deferred Compensation Arrangement With Individual Share Based Payments [Line Items]
Number of annual installment in which stock option exercisable (in installments)	3
Period from grant date for annual installment (in years)	1 year
Restricted stock (in shares) \| shares	147,851
Fair value grant (in dollars per share) \| $ / shares	$ 9.66
Cash incentive award \| Suncoke LTCIP
Deferred Compensation Arrangement With Individual Share Based Payments [Line Items]
Grant date fair value of award \| $	$ 0.6
Percent of award allocation	50.00%
Measurement period	3 years
Cash incentive award \| Maximum \| Suncoke LTCIP
Deferred Compensation Arrangement With Individual Share Based Payments [Line Items]
Percent of original award granted	250.00%

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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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Stock option expiration period.

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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
-Paragraph 1
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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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