Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 Segment	Sep. 30, 2011	Dec. 31, 2011
Segment Information
Number of reporting segments			3
Segment Reporting Information
Net Sales, External	$ 1,580,628	$ 1,915,519	$ 5,249,997	$ 5,768,926
Net Sales, External Non-U.S.	112,762	127,936	335,236	370,229
Total net sales	1,693,390	2,043,455	5,585,233	6,139,155
Operating income (loss)	72,721	108,785	296,236	502,330
Income (loss) before income taxes	7,221	67,606	140,162	383,305
Depreciation and amortization	58,953	55,962	170,027	166,965
Capital expenditures	58,342	38,126	158,686	91,795
Assets	5,775,516	6,003,481	5,775,516	6,003,481	5,979,226
Liabilities	3,342,688	3,656,451	3,342,688	3,656,451
Steel Operations
Segment Reporting Information
Net Sales, External	985,524	1,183,665	3,279,344	3,551,626
Net Sales, External Non-U.S.	65,825	44,345	166,025	138,723
Net Sales, Other segments	48,157	49,854	148,839	163,991
Total net sales	1,099,506	1,277,864	3,594,208	3,854,340
Operating income (loss)	106,927	136,194	380,832	543,117
Income (loss) before income taxes	88,394	114,805	325,521	480,296
Depreciation and amortization	25,937	27,320	78,405	82,164
Capital expenditures	14,625	10,457	26,848	28,891
Assets	2,523,616	2,629,873	2,523,616	2,629,873
Liabilities	482,348	488,476	482,348	488,476
Metals Recycling and Ferrous Resources Operations
Segment Reporting Information
Net Sales, External	475,547	624,742	1,643,522	1,944,928
Net Sales, External Non-U.S.	46,684	83,296	168,818	230,954
Net Sales, Other segments	268,137	351,219	1,009,604	1,069,661
Total net sales	790,368	1,059,257	2,821,944	3,245,543
Operating income (loss)	(15,697)	(3,388)	(30,905)	39,987
Income (loss) before income taxes	(24,829)	(14,697)	(57,932)	8,033
Depreciation and amortization	26,449	25,164	78,114	75,784
Capital expenditures	42,370	26,575	127,133	58,458
Assets	2,586,568	2,557,147	2,586,568	2,557,147
Liabilities	507,367	531,827	507,367	531,827
Steel Fabrication Operations
Segment Reporting Information
Net Sales, External	102,401	83,094	273,060	197,112
Net Sales, Other segments	41	16	45	612
Total net sales	102,442	83,110	273,105	197,724
Operating income (loss)	3,141	(246)	666	(4,764)
Income (loss) before income taxes	1,225	(2,139)	(4,408)	(9,918)
Depreciation and amortization	2,100	1,847	6,007	4,969
Capital expenditures	1,005	503	3,502	1,454
Assets	249,988	234,452	249,988	234,452
Liabilities	18,143	16,820	18,143	16,820
Other
Segment Reporting Information
Net Sales, External	17,156	24,018	54,071	75,260
Net Sales, External Non-U.S.	253	295	393	552
Net Sales, Other segments	4,864	3,033	12,290	8,452
Total net sales	22,273	27,346	66,754	84,264
Operating income (loss)	(17,759)	(28,437)	(49,294)	(78,115)
Income (loss) before income taxes	(53,678)	(35,025)	(117,956)	(97,105)
Depreciation and amortization	4,518	1,682	7,654	4,201
Capital expenditures	342	591	1,203	2,992
Assets	597,297	757,275	597,297	757,275
Liabilities	2,505,036	2,785,613	2,505,036	2,785,613
Eliminations
Segment Reporting Information
Net Sales, Other segments	(321,199)	(404,122)	(1,170,778)	(1,242,716)
Total net sales	(321,199)	(404,122)	(1,170,778)	(1,242,716)
Operating income (loss)	(3,891)	4,662	(5,063)	2,105
Income (loss) before income taxes	(3,891)	4,662	(5,063)	1,999
Depreciation and amortization	(51)	(51)	(153)	(153)
Assets	(181,953)	(175,266)	(181,953)	(175,266)
Liabilities	$ (170,206)	$ (166,285)	$ (170,206)	$ (166,285)