Summary of Significant Accounting Policies, Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Significant accounting policies
Reclassification of deferred financing costs upon adoption of ASU 2015-03	$ 3.2
Inventory Write-down	4.9	$ 0.0
Fabricated Products
Significant accounting policies
(Shortfalls) excess of current cost over the stated LIFO value of inventory	$ 17.7		$ 24.1