Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 segment	Jun. 30, 2012	Dec. 31, 2012
Segment Information
Number of reporting segments			3
Segment Reporting Information
Net Sales, External	$ 1,701,890	$ 1,803,699	$ 3,383,864	$ 3,669,369
Net Sales, External Non-U.S.	99,450	106,104	213,172	222,474
Total net sales	1,801,340	1,909,803	3,597,036	3,891,843
Operating income (loss)	69,198	103,699	165,430	223,515
Income (loss) before income taxes	38,979	64,485	101,628	132,941
Depreciation and amortization	56,826	55,502	113,887	111,074
Capital expenditures	49,236	54,789	94,582	100,344
Assets	5,735,910	5,971,380	5,735,910	5,971,380	5,815,416
Liabilities	3,220,439	3,539,820	3,220,439	3,539,820
Steel Operations
Segment Reporting Information
Net Sales, External	1,038,868	1,157,908	2,050,063	2,293,820
Net Sales, External Non-U.S.	52,148	49,392	102,265	100,200
Net Sales, Other segments	52,897	52,923	113,945	100,682
Total net sales	1,143,913	1,260,223	2,266,273	2,494,702
Operating income (loss)	85,545	136,597	204,846	273,905
Income (loss) before income taxes	71,732	118,049	176,739	237,127
Depreciation and amortization	26,496	26,384	52,883	52,468
Capital expenditures	34,533	6,275	59,259	12,223
Assets	2,582,168	2,604,810	2,582,168	2,604,810
Liabilities	512,634	464,861	512,634	464,861
Metals Recycling and Ferrous Resources Operations
Segment Reporting Information
Net Sales, External	538,599	533,841	1,096,210	1,167,975
Net Sales, External Non-U.S.	46,893	56,668	110,410	122,134
Net Sales, Other segments	275,666	329,947	552,030	741,467
Total net sales	861,158	920,456	1,758,650	2,031,576
Operating income (loss)	(7,251)	(19,371)	(17,075)	(15,208)
Income (loss) before income taxes	(14,439)	(28,830)	(32,293)	(33,103)
Depreciation and amortization	26,704	25,591	53,840	51,665
Capital expenditures	13,545	46,857	32,614	84,763
Assets	2,490,215	2,607,834	2,490,215	2,607,834
Liabilities	522,306	574,204	522,306	574,204
Steel Fabrication Operations
Segment Reporting Information
Net Sales, External	103,595	95,767	197,392	170,659
Net Sales, Other segments	564		1,142	4
Total net sales	104,159	95,767	198,534	170,663
Operating income (loss)	2,330	193	3,860	(2,475)
Income (loss) before income taxes	800	(1,449)	724	(5,633)
Depreciation and amortization	2,179	2,059	4,236	3,907
Capital expenditures	822	1,329	1,703	2,497
Assets	261,556	255,967	261,556	255,967
Liabilities	16,136	14,807	16,136	14,807
Other
Segment Reporting Information
Net Sales, External	20,828	16,183	40,199	36,915
Net Sales, External Non-U.S.	409	44	497	140
Net Sales, Other segments	6,885	4,164	12,280	7,426
Total net sales	28,122	20,391	52,976	44,481
Operating income (loss)	(14,434)	(14,673)	(30,873)	(31,535)
Income (loss) before income taxes	(22,122)	(24,238)	(48,214)	(64,278)
Depreciation and amortization	1,498	1,519	3,030	3,136
Capital expenditures	336	328	1,006	861
Assets	604,195	725,717	604,195	725,717
Liabilities	2,362,721	2,699,661	2,362,721	2,699,661
Eliminations
Segment Reporting Information
Net Sales, Other segments	(336,012)	(387,034)	(679,397)	(849,579)
Total net sales	(336,012)	(387,034)	(679,397)	(849,579)
Operating income (loss)	3,008	953	4,672	(1,172)
Income (loss) before income taxes	3,008	953	4,672	(1,172)
Depreciation and amortization	(51)	(51)	(102)	(102)
Assets	(202,224)	(222,948)	(202,224)	(222,948)
Liabilities	$ (193,358)	$ (213,713)	$ (193,358)	$ (213,713)