Accrued Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Accrued Liabilities [Abstract]
Compensation and benefits	$ 109.9	$ 130.8
Medical insurance and workers’ compensation	31.0	27.0
Franchise, property, and sales and use taxes	23.3	17.5
Customer volume discounts and rebates	14.6	13.9
Environmental liabilities and asset retirement obligations	9.1	7.1
Severance, retention, and relocation	9.5	8.3
Other	11.6	15.4
Total	$ 209.0	$ 220.0