Commitments and Contingencies (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended	12 Months Ended		3 Months Ended	9 Months Ended	0 Months Ended			3 Months Ended
	Jun. 30, 2010	Dec. 31, 2012	Mar. 31, 2014	Mar. 31, 2014 Environmental Matters Walter Coke, Inc. item	Sep. 30, 2013 Environmental Matters Walter Coke, Inc. item	May 30, 2012 Securities Class Actions and Shareholder Derivative Actions item	Mar. 15, 2012 Securities Class Actions and Shareholder Derivative Actions item	Jan. 26, 2012 Securities Class Actions and Shareholder Derivative Actions item	Mar. 31, 2014 Securities Class Actions and Shareholder Derivative Actions item
Commitments and contingencies
Extension period to submit proposed final order	90 days
Comment letter period	30 days	30 days
Accruals for unrecognized tax benefits related to disposition			$ 35.0
Number of properties that the entity has agreed to remediate				23
Number of other PRP's in which "Offer to Conduct Work" letter was sent to					4
Number of residential properties whose sampling has been completed by EPA					1,100
Number of properties exceeding Regional Removal Management Levels (RML's)					400
Number of Phase I properties offered to Potentially Responsible Parties PRP's for cleanup					50
Number of executive directors as defendants							3	3
Number of actions						2
Number of complaints									3