Other Accrued Liabilities (Details) (USD $)
In Millions, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Other accrued liabilities    
Compensation and other employee benefits $ 13.1 $ 22.1
Construction in progress accruals 9.4 2.8
Accrued interest 8.7 16.6
Other accrued expense 20.0 20.7
Total other accrued liabilities $ 51.2 $ 62.2