ACQUISITION (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
KA Steel [Member]
Business Acquisition [Line Items]
Sales	$ 686.9	$ 656.2	$ 1,879.8	$ 1,803.4
Net income	39.3	44.5	124.9	220.4
Net income per common share-basic (in dollars per share)	$ 0.49	$ 0.56	$ 1.56	$ 2.76
Net income per common share-diluted (in dollars per share)	$ 0.48	$ 0.55	$ 1.54	$ 2.73
SunBelt [Member]
Business Acquisition [Line Items]
Sales				1,541.6
Net income				$ 121.9
Net income per common share-basic (in dollars per share)				$ 1.53
Net income per common share-diluted (in dollars per share)				$ 1.51