Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Segment Information
Number of reporting segments (as a number)			3
Segment Reporting Information
Net Sales, External	$ 1,956,974	$ 1,558,155	$ 3,853,407	$ 3,027,829
Net Sales, External Non-U.S.	122,757	74,644	242,293	160,760
Total net sales	2,079,731	1,632,799	4,095,700	3,188,589
Operating income	188,219	116,635	393,545	248,932
Income (loss) before income taxes	149,152	76,708	315,699	174,571
Depreciation and amortization	56,257	55,398	111,003	111,670
Capital expenditures	34,976	40,960	53,669	71,644
Assets	5,900,453	5,545,805	5,900,453	5,545,805	5,589,934
Liabilities	3,588,965	3,448,206	3,588,965	3,448,206
Steel Operations
Segment Reporting Information
Net Sales, External	1,221,472	954,589	2,367,961	1,897,807
Net Sales, External Non-U.S.	45,803	22,048	94,378	51,397
Net Sales, Other segments	62,191	43,292	114,137	83,221
Total net sales	1,329,466	1,019,929	2,576,476	2,032,425
Operating income	213,968	131,146	406,923	265,884
Income (loss) before income taxes	192,782	111,778	365,491	229,666
Depreciation and amortization	27,651	28,138	54,844	56,298
Capital expenditures	11,155	17,146	18,434	29,217
Assets	2,712,461	2,548,149	2,712,461	2,548,149
Liabilities	467,195	409,311	467,195	409,311
Metals Recycling and Ferrous Resources Operations
Segment Reporting Information
Net Sales, External	647,845	537,519	1,320,186	1,012,936
Net Sales, External Non-U.S.	76,834	52,406	147,658	109,052
Net Sales, Other segments	353,192	258,442	718,442	482,682
Total net sales	1,077,871	848,367	2,186,286	1,604,670
Operating income	3,885	6,939	43,375	31,073
Income (loss) before income taxes	(6,354)	(7,238)	22,730	6,175
Depreciation and amortization	25,706	24,443	50,620	50,127
Capital expenditures	21,632	13,682	31,883	31,358
Assets	2,536,751	2,438,573	2,536,751	2,438,573
Liabilities	563,908	569,956	563,908	569,956
Steel Fabrication Operations
Segment Reporting Information
Net Sales, External	61,939	42,266	114,018	66,227
Net Sales, Other segments	23	1	596	38
Total net sales	61,962	42,267	114,614	66,265
Operating income	(1,635)	(4,713)	(4,518)	(11,293)
Income (loss) before income taxes	(3,334)	(6,021)	(7,779)	(13,777)
Depreciation and amortization	1,620	1,739	3,122	3,112
Capital expenditures	419	43	951	150
Assets	229,988	194,125	229,988	194,125
Liabilities	16,715	20,957	16,715	20,957
Other
Segment Reporting Information
Net Sales, External	25,718	23,781	51,242	50,859
Net Sales, External Non-U.S.	120	190	257	311
Net Sales, Other segments	2,948	2,501	5,419	4,720
Total net sales	28,786	26,472	56,918	55,890
Operating income	(25,422)	(16,820)	(49,678)	(35,695)
Income (loss) before income taxes	(31,338)	(21,816)	(62,080)	(45,739)
Depreciation and amortization	1,331	1,136	2,519	2,218
Capital expenditures	1,770	10,089	2,401	11,557
Assets	632,242	628,888	632,242	628,888
Liabilities	2,740,245	2,705,058	2,740,245	2,705,058
Eliminations
Segment Reporting Information
Net Sales, Other segments	(418,354)	(304,236)	(838,594)	(570,661)
Total net sales	(418,354)	(304,236)	(838,594)	(570,661)
Operating income	(2,577)	83	(2,557)	(1,037)
Income (loss) before income taxes	(2,604)	5	(2,663)	(1,754)
Depreciation and amortization	(51)	(58)	(102)	(85)
Capital expenditures				(638)
Assets	(210,989)	(263,930)	(210,989)	(263,930)
Liabilities	$ (199,098)	$ (257,076)	$ (199,098)	$ (257,076)