Share-Based Compensation (Details Textual) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended			9 Months Ended	3 Months Ended	9 Months Ended		3 Months Ended	9 Months Ended	3 Months Ended			3 Months Ended					3 Months Ended	9 Months Ended		3 Months Ended
	Mar. 31, 2013	Mar. 31, 2013 Options granted current period [Member] installment	Mar. 31, 2013 Performance Shares [Member]	Sep. 30, 2012 Performance Shares [Member]	Mar. 31, 2013 Restricted Stock Units (RSUs) [Member] installment	Sep. 30, 2012 Restricted Stock Units (RSUs) [Member]	Sep. 30, 2011 Restricted Stock Units (RSUs) [Member]	Mar. 31, 2013 Stock Options [Member]	Sep. 30, 2012 Stock Options [Member]	Mar. 31, 2013 Distribution first [Member] Modified Options Sunoco Employees [Member]	Dec. 31, 2012 Distribution first [Member] Modified Options Sunoco Employees [Member]	Jan. 17, 2012 Distribution first [Member] Modified Options Sunoco Employees [Member]	Mar. 31, 2013 Distribution first [Member] Performance Shares [Member] Units Awarded During Period [Member]	Mar. 31, 2013 Distribution first [Member] Restricted Stock Units (RSUs) [Member] Units Awarded During Period [Member]	Mar. 31, 2013 Distribution Second [Member] Modified Options [Member]	Mar. 31, 2012 Distribution Second [Member] Modified Options [Member]	Jan. 17, 2012 Distribution Second [Member] Modified Options [Member]	Mar. 31, 2013 Distribution Second [Member] Restricted Stock Units (RSUs) [Member] Modified Units [Member]	Sep. 30, 2012 Distribution Second [Member] Restricted Stock Units (RSUs) [Member] Modified Units [Member]	Jan. 17, 2012 Distribution Second [Member] Restricted Stock Units (RSUs) [Member] Modified Units [Member]	Mar. 31, 2013 Minimum [Member] Performance Shares [Member]	Mar. 31, 2013 Maximum [Member] Performance Shares [Member]
Share-based compensation (Textual) [Abstract]
Granted Stock Options		444,377
Number of annual installment in which stock option exercisable		3			3
Period from grant date for annual installment		1 year			1 year
Stock Option Time Until Expiration		10 years								10 years					10 years
Weighted-average fair value stock option		$ 6.00
Forfeiture Rate	3.00%				3.00%
Nonvested, Number			96,073															7,897
Stock option outstanding								2,317,785
Compensation expense				$ 0.1		$ 0.3	$ 0.4		$ 0.9										$ 0.1
Unrecognized compensation cost			1.8		7.3			8.5
Weighted average remaining contractual term			2 years 9 months 18 days		2 years 8 months 12 days			2 years							5 years 6 months
Restricted Stock													96,073	268,982
Fair value grant													$ 19.56	$ 16.55
Percentage of Award Determined by the Company's Three Year Tsr			50.00%
Number of Years of Total Shareholder Return			3 years
Terms of Award, Percentage Adjustment of Award Determined by TSR																					0.00%	200.00%
Percentage of Award Determined by Pre-Tax Return on Capital			50.00%
Number of Years of Pre-Tax Return on Capital			3 years
Percentage Adjustment of Award Determined by Pre-Tax Return on Capital																					0.00%	200.00%
Restricted units outstanding					545,782
Weighted average period																		1 year
Modified Options Granted Sonoco Employees												1,219,842
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number											638,669
Modified Options SunCoke Employees																	295,854
Stock option range lower										$ 4.77					$ 8.93
Stock option range upper										$ 29.35					$ 22.31
Anti-dilution provision																$ 0.5
Stock option vested															282,277
Weighted average remaining life										4 years
Stock option exercised										61,847
Sonoco Units Converted to SunCoke Units																				95,984
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested, Number																		88,087