Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014 segment	Jun. 30, 2013	Dec. 31, 2013
Segment Information
Number of reporting segments			3
Segment Reporting Information
Total net sales	$ 2,069,761	$ 1,801,340	$ 3,899,843	$ 3,597,036
Operating income (loss)	131,905	69,198	212,837	165,430
Income (loss) before income taxes	103,609	38,979	154,603	101,628
Depreciation and amortization	58,441	56,826	116,009	113,887
Capital expenditures	33,534	49,236	58,375	94,582
Assets	5,985,202	5,735,910	5,985,202	5,735,910	5,933,006
Liabilities	3,025,992	3,220,439	3,025,992	3,220,439
U [S]
Segment Reporting Information
Total net sales	1,960,665	1,701,890	3,676,183	3,383,864
Foreign Countries [Member]
Segment Reporting Information
Total net sales	109,096	99,450	223,660	213,172
Steel Operations [Member]
Segment Reporting Information
Capital expenditures	16,332	34,533	34,938	59,259
Metals Recycling And Ferrous Resources Operations [Member]
Segment Reporting Information
Capital expenditures	16,384	13,545	22,163	32,614
Steel Fabrication Operations [Member]
Segment Reporting Information
Capital expenditures	536	822	847	1,703
Corporate And Other [Member]
Segment Reporting Information
Capital expenditures	282	336	427	1,006
Operating Segments [Member]
Segment Reporting Information
Total net sales	2,069,761	1,801,340	3,899,843	3,597,036
Operating Segments [Member] | Steel Operations [Member]
Segment Reporting Information
Total net sales	1,334,906	1,143,913	2,496,236	2,266,273
Operating income (loss)	155,949	85,545	261,592	204,846
Income (loss) before income taxes	142,594	71,732	234,592	176,739
Depreciation and amortization	28,869	26,496	56,246	52,883
Assets	2,732,388	2,582,168	2,732,388	2,582,168
Liabilities	578,124	512,634	578,124	512,634
Operating Segments [Member] | Steel Operations [Member] | Other Segments [Member]
Segment Reporting Information
Total net sales	69,802	52,897	113,534	113,945
Operating Segments [Member] | Steel Operations [Member] | U [S]
Segment Reporting Information
Total net sales	1,214,247	1,038,868	2,275,326	2,050,063
Operating Segments [Member] | Steel Operations [Member] | Foreign Countries [Member]
Segment Reporting Information
Total net sales	50,857	52,148	107,376	102,265
Operating Segments [Member] | Metals Recycling And Ferrous Resources Operations [Member]
Segment Reporting Information
Total net sales	948,833	861,158	1,868,535	1,758,650
Operating income (loss)	(6,053)	(7,251)	(21,572)	(17,075)
Income (loss) before income taxes	(12,634)	(14,439)	(35,330)	(32,293)
Depreciation and amortization	25,870	26,704	52,491	53,840
Assets	2,551,899	2,490,215	2,551,899	2,490,215
Liabilities	640,459	522,306	640,459	522,306
Operating Segments [Member] | Metals Recycling And Ferrous Resources Operations [Member] | Other Segments [Member]
Segment Reporting Information
Total net sales	303,617	275,666	647,545	552,030
Operating Segments [Member] | Metals Recycling And Ferrous Resources Operations [Member] | U [S]
Segment Reporting Information
Total net sales	587,385	538,599	1,105,342	1,096,210
Operating Segments [Member] | Metals Recycling And Ferrous Resources Operations [Member] | Foreign Countries [Member]
Segment Reporting Information
Total net sales	57,831	46,893	115,648	110,410
Operating Segments [Member] | Steel Fabrication Operations [Member]
Segment Reporting Information
Total net sales	134,852	104,159	250,713	198,534
Operating income (loss)	7,590	2,330	10,716	3,860
Income (loss) before income taxes	6,099	800	7,751	724
Depreciation and amortization	2,401	2,179	4,623	4,236
Assets	297,149	261,556	297,149	261,556
Liabilities	20,879	16,136	20,879	16,136
Operating Segments [Member] | Steel Fabrication Operations [Member] | Other Segments [Member]
Segment Reporting Information
Total net sales		564		1,142
Operating Segments [Member] | Steel Fabrication Operations [Member] | U [S]
Segment Reporting Information
Total net sales	134,852	103,595	250,713	197,392
Operating Segments [Member] | Corporate And Other [Member]
Segment Reporting Information
Total net sales	31,898	28,122	59,420	52,976
Operating income (loss)	(24,159)	(14,434)	(40,704)	(30,873)
Income (loss) before income taxes	(31,028)	(22,122)	(55,215)	(48,214)
Depreciation and amortization	1,352	1,498	2,751	3,030
Assets	624,518	604,195	624,518	604,195
Liabilities	1,996,306	2,362,721	1,996,306	2,362,721
Operating Segments [Member] | Corporate And Other [Member] | Other Segments [Member]
Segment Reporting Information
Total net sales	7,309	6,885	13,982	12,280
Operating Segments [Member] | Corporate And Other [Member] | U [S]
Segment Reporting Information
Total net sales	24,181	20,828	44,802	40,199
Operating Segments [Member] | Corporate And Other [Member] | Foreign Countries [Member]
Segment Reporting Information
Total net sales	408	409	636	497
Intersegment Elimination [Member]
Segment Reporting Information
Total net sales	(380,728)	(336,012)	(775,061)	(679,397)
Operating income (loss)	(1,422)	3,008	2,805	4,672
Income (loss) before income taxes	(1,422)	3,008	2,805	4,672
Depreciation and amortization	(51)	(51)	(102)	(102)
Assets	(220,752)	(202,224)	(220,752)	(202,224)
Liabilities	(209,776)	(193,358)	(209,776)	(193,358)
Intersegment Elimination [Member] | Other Segments [Member]
Segment Reporting Information
Total net sales	$ (380,728)	$ (336,012)	$ (775,061)	$ (679,397)