Share-Based Compensation - Performance Share Units (Details) - PSUs - Suncoke LTPEP	6 Months Ended
	Jun. 30, 2017 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted (in shares) | shares	237,610
Fair Value per Share (in dollars per share) | $ / shares	$ 11.40
Measurement period	3 years
Pre-tax return of capital for Coke and Coal Logistics businesses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of award allocation	50.00%
Measurement period	3 years
TSR
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Measurement period	3 years
TSR | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Measurement results payout percentage	50.00%
TSR | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Measurement results payout percentage	150.00%