Summary of Significant Accounting Policies, Textuals, Property, Plant and Equipment (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Property, Plant and Equipment
Interest expense capitalized as construction in progress	$ 0.3	$ 1.0	$ 2.2	$ 2.1
Other operating charges, net	(1.3)	0	(1.5)	0
Depreciation expense			21.9	19.6
Fabricated Products
Property, Plant and Equipment
Depreciation expense	$ 7.4	$ 6.3	$ 21.5	$ 19.3