Summary of Significant Accounting Policies, Textuals, Property, Plant and Equipment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Property, Plant and Equipment
Interest expense capitalized as construction in progress	$ 0.4	$ 0.8	$ 0.7	$ 1.9
Depreciation expense			15.3	14.3
Fabricated Products
Property, Plant and Equipment
Depreciation expense	$ 7.6	$ 7.3	$ 15.1	$ 14.1