Additional Balance Sheet Information (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Inventories
Crude stockpile inventories	$ 58.4	$ 54.6
In-process and finished goods inventories	67.3	66.0
Other raw material, container, and supplies inventories	24.9	26.0
Inventory, Net, Total	$ 150.6	$ 146.6	[1]

[1] *Condensed from audited financial statements.