Summary of Significant Accounting Policies, Textuals, Property, Plant and Equipment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Property, Plant and Equipment
Interest expense capitalized as construction in progress	$ 0.4	$ 0.3	$ 1.1	$ 2.2
Non-cash impairment charges		1.3	0.0	1.5
Depreciation expense			23.0	21.9
Fabricated Products
Property, Plant and Equipment
Depreciation expense	$ 7.5	$ 7.4	$ 22.6	$ 21.5