Income Taxes (Deferred Tax Liability) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014
Deferred income tax assets:
Inventory	$ 0.2
Accrued expenses	0.3
Asset retirement obligations	2.2
Net operating loss carryforward-non current	23.9
Total deferred tax assets	26.6
Deferred income tax liabilities:
Property, plant, equipment, and intangibles assets-long term	515.1
Other assets	8.1
Total deferred tax liabilities	523.2
Net deferred tax liability	$ 496.6