DEBT (Detail Textuals) (USD $) In Millions, unless otherwise specified	12 Months Ended								1 Months Ended		12 Months Ended														12 Months Ended		12 Months Ended		12 Months Ended			12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2010 Recovery Zone Tax-Exempt Bonds due 2035 [Member]	Dec. 31, 2010 Recovery Zone tax Exempt Bonds due 2033 [Member]	Dec. 31, 2012 Recovery Zone tax Exempt Bonds due 2033 [Member]	Dec. 31, 2010 Tax Exempt Bonds Go Zone due 2024 [Member]	Dec. 31, 2010 Tax Exempt Bonds Recovery Zone due 2024 [Member]	Oct. 31, 2010 Industrial Revenue Bond [Member]	Sep. 30, 2010 Industrial Revenue Bond [Member]	Dec. 31, 2012 Industrial Revenue Bond [Member]	Dec. 31, 2012 SunBelt Notes [Member]	Dec. 31, 2011 SunBelt Notes [Member]	Dec. 31, 2012 Notes payable due 2011 [Member]	Dec. 31, 2011 Tax Exempt Bond [Member]	Dec. 31, 2010 Tax Exempt Bond [Member]	Dec. 31, 2011 Variable Interest Rate Swaps $75M [Member]	Jan. 01, 2009 Variable Interest Rate Swaps $75M [Member]	Dec. 31, 2012 Variable Interest Rate Swaps $125M [Member]	Oct. 31, 2011 Variable Interest Rate Swaps $125M [Member]	Dec. 31, 2011 Fixed Interest Rate Swaps 75M [Member]	Dec. 31, 2012 Fixed Interest Rate Swaps $125M [Member]	Dec. 31, 2012 SunBelt Notes [Member]	Jun. 30, 2012 SunBelt Notes [Member]	Dec. 31, 2012 Guaranteed Senior Secured Notes due 2017, Series G [Member]	Dec. 22, 1997 Guaranteed Senior Secured Notes due 2017, Series G [Member]	Dec. 31, 2012 Guaranteed Senior Secured Notes due 2017, Series O [Member]	Dec. 22, 1997 Guaranteed Senior Secured Notes due 2017, Series O [Member]	Dec. 31, 2012 SunBelt [Member]	Feb. 28, 2011 SunBelt [Member]	Dec. 22, 1997 SunBelt [Member]	Dec. 31, 2012 KA Steel [Member]	Aug. 22, 2012 KA Steel [Member]
Debt Instrument [Line Items]
Long Term Debt Net Proceeds																																$ 196.0
Payments of Debt Issuance Costs	6.0	0	1.0																													4.0
Underlying debt instrument [Abstract]
Swap Amount																	75.0		125.0		75.0	125.0	73.1
Amount of gain included in long-term debt										0.3	0.2							7.9	8.4	11.0			1.8	2.2
Reduction in interest expense due to interest rate swaps	3.4	7.2	7.0
Revolving credit facility [Abstract]
Maximum amount of senior revolving credit facility	265
Available credit under senior revolving credit facility	233.3
Previous Maximum borrowing capacity under credit facility	240
Previous Letter of Credit Subfacility	25
Amount of letters of credit issued under subfacility	31.7
SubfacilityOfSeniorCreditFacitility	110
CanadianSubfacilityOfSeniorCreditFacitility	50
Total letters of credit outstanding	35.8
Long-term debt [Abstract]
Notes payable	713.7	536.4		41.0	42.0		50.0	20.0				63.9	76.6			70.0
Interest rate swap												1.8	1.9
Interest rate												7.23%	7.23%																7.23%		7.23%
Amounts due within one year	23.6	12.2
Total long-term debt	690.1	524.2
Drawings on notes				41.0	42.0										36.0	34.0
Amount of bond proceeds with trustee classified as noncurrent assets	11.9	51.7				11.9
Unamortized fair value premium												1.1	1.6
Industrial revenue bond activity [Abstract]
Redemption of industrial revenue bonds									1.8	18.9	7.7
Premium paid to the bond holders										0.4	0.2
Deferred gain recognized										0.3	0.2							7.9	8.4	11.0			1.8	2.2
Long Term Debt Repayments [Abstract]
Long-Term Debt Repayments												12.2	12.2	75.0
Long Term Debt Repayment [Abstract]
Face amount of senior secured notes																										97.5		97.5					200.0
Interest rate												7.23%	7.23%																7.23%		7.23%
Required annual debt repayment for Series O and Series G notes																									6.1		6.1		12.2
Fair value of acquired debt																														87.3
Remaining principal balance of consolidated notes																														85.3
Long-Term Debt Repayments												12.2	12.2	75.0
Expected maturities of long-term debt [Abstract]
2013	23.6
2014	12.2
2015	12.2
2016	145.6
2017	15.1
Thereafter	$ 505.0