Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 segment	Sep. 30, 2012	Dec. 31, 2012
Segment Information
Number of reporting segments			3
Segment Reporting Information
Net Sales, External	$ 1,803,540	$ 1,580,628	$ 5,187,404	$ 5,249,997
Net Sales, External Non-U.S.	108,198	112,762	321,370	335,236
Total net sales	1,911,738	1,693,390	5,508,774	5,585,233
Operating income (loss)	113,273	72,721	278,703	296,236
Income (loss) before income taxes	84,155	7,221	185,783	140,162
Depreciation and amortization	58,202	58,953	172,089	170,027
Capital expenditures	52,162	58,342	146,744	158,686
Assets	5,874,305	5,775,516	5,874,305	5,775,516	5,815,416
Liabilities	3,316,517	3,342,688	3,316,517	3,342,688
Steel Operations
Segment Reporting Information
Net Sales, External	1,102,048	985,524	3,152,111	3,279,344
Net Sales, External Non-U.S.	60,381	65,825	162,646	166,025
Net Sales, Other segments	54,537	48,157	168,482	148,839
Total net sales	1,216,966	1,099,506	3,483,239	3,594,208
Operating income (loss)	146,564	106,927	351,410	380,832
Income (loss) before income taxes	133,041	88,394	309,780	325,521
Depreciation and amortization	26,815	25,937	79,698	78,405
Capital expenditures	33,985	14,625	93,244	26,848
Assets	2,581,798	2,523,616	2,581,798	2,523,616
Liabilities	533,966	482,348	533,966	482,348
Metals Recycling and Ferrous Resources Operations
Segment Reporting Information
Net Sales, External	557,765	475,547	1,653,975	1,643,522
Net Sales, External Non-U.S.	47,616	46,684	158,026	168,818
Net Sales, Other segments	313,113	268,137	865,143	1,009,604
Total net sales	918,494	790,368	2,677,144	2,821,944
Operating income (loss)	(17,135)	(15,697)	(34,210)	(30,905)
Income (loss) before income taxes	(24,567)	(24,829)	(56,860)	(57,932)
Depreciation and amortization	27,713	26,449	81,553	78,114
Capital expenditures	17,385	42,370	49,999	127,133
Assets	2,530,979	2,586,568	2,530,979	2,586,568
Liabilities	593,674	507,367	593,674	507,367
Steel Fabrication Operations
Segment Reporting Information
Net Sales, External	119,134	102,401	316,526	273,060
Net Sales, Other segments	134	41	1,276	45
Total net sales	119,268	102,442	317,802	273,105
Operating income (loss)	3,265	3,141	7,125	666
Income (loss) before income taxes	1,751	1,225	2,475	(4,408)
Depreciation and amortization	2,219	2,100	6,455	6,007
Capital expenditures	297	1,005	2,000	3,502
Assets	272,786	249,988	272,786	249,988
Liabilities	22,908	18,143	22,908	18,143
Other
Segment Reporting Information
Net Sales, External	24,593	17,156	64,792	54,071
Net Sales, External Non-U.S.	201	253	698	393
Net Sales, Other segments	7,918	4,864	20,198	12,290
Total net sales	32,712	22,273	85,688	66,754
Operating income (loss)	(17,274)	(17,759)	(48,147)	(49,294)
Income (loss) before income taxes	(23,922)	(53,678)	(72,136)	(117,956)
Depreciation and amortization	1,506	4,518	4,536	7,654
Capital expenditures	495	342	1,501	1,203
Assets	699,244	597,297	699,244	597,297
Liabilities	2,366,273	2,505,036	2,366,273	2,505,036
Eliminations
Segment Reporting Information
Net Sales, Other segments	(375,702)	(321,199)	(1,055,099)	(1,170,778)
Total net sales	(375,702)	(321,199)	(1,055,099)	(1,170,778)
Operating income (loss)	(2,147)	(3,891)	2,525	(5,063)
Income (loss) before income taxes	(2,148)	(3,891)	2,524	(5,063)
Depreciation and amortization	(51)	(51)	(153)	(153)
Assets	(210,502)	(181,953)	(210,502)	(181,953)
Liabilities	$ (200,304)	$ (170,206)	$ (200,304)	$ (170,206)