ACQUISITION (Details 2) (KA Steel [Member], USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2012
KA Steel [Member]
Business Acquisition [Line Items]
Sales	$ 648.9	$ 1,879.8
Net income	$ 38.7	$ 125.6
Net income per common share-basic (in dollars per share)	$ 0.48	$ 1.57
Net income per common share-diluted (in dollars per share)	$ 0.48	$ 1.55