Segment Information - Results (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Segment Reporting Information
Net sales	$ 4,893,206	$ 5,569,902
Operating income (loss)	835,360	1,494,867
Income (loss) before income taxes	847,789	1,457,730
Depreciation and amortization	107,694	87,546
Capital expenditures	226,319	159,330
Assets	14,219,760		$ 14,159,984
U.S.
Segment Reporting Information
Net sales	4,451,020	5,248,208
Non-U.S.
Segment Reporting Information
Net sales	442,186	321,694
Operating Segment | Steel Operations
Segment Reporting Information
Net sales	3,185,631	3,931,653
Operating income (loss)	341,760	1,163,010
Income (loss) before income taxes	342,500	1,152,216
Depreciation and amortization	83,476	66,682
Capital expenditures	120,539	136,190
Assets	8,615,026
Operating Segment | Steel Operations | Other segments
Segment Reporting Information
Net sales	124,810	169,157
Operating Segment | Steel Operations | U.S.
Segment Reporting Information
Net sales	2,847,186	3,573,202
Operating Segment | Steel Operations | Non-U.S.
Segment Reporting Information
Net sales	213,635	189,294
Operating Segment | Metals Recycling Operations
Segment Reporting Information
Net sales	1,161,927	1,143,217
Operating income (loss)	39,688	44,960
Income (loss) before income taxes	45,549	45,730
Depreciation and amortization	14,365	13,254
Capital expenditures	19,697	11,557
Assets	1,416,914
Operating Segment | Metals Recycling Operations | Other segments
Segment Reporting Information
Net sales	578,459	563,592
Operating Segment | Metals Recycling Operations | U.S.
Segment Reporting Information
Net sales	382,803	448,043
Operating Segment | Metals Recycling Operations | Non-U.S.
Segment Reporting Information
Net sales	200,665	131,582
Operating Segment | Steel Fabrication Operations
Segment Reporting Information
Net sales	868,804	930,100
Operating income (loss)	551,272	466,875
Income (loss) before income taxes	551,412	465,199
Depreciation and amortization	2,331	2,430
Capital expenditures	4,496	3,690
Assets	1,180,335
Operating Segment | Steel Fabrication Operations | Other segments
Segment Reporting Information
Net sales	36	119
Operating Segment | Steel Fabrication Operations | U.S.
Segment Reporting Information
Net sales	868,702	929,842
Operating Segment | Steel Fabrication Operations | Non-U.S.
Segment Reporting Information
Net sales	66	139
Operating Segment | Other
Segment Reporting Information
Net sales	380,149	298,458
Operating income (loss)	(98,940)	(174,535)
Income (loss) before income taxes	(92,896)	(199,629)
Depreciation and amortization	7,522	5,180
Capital expenditures	81,587	7,893
Assets	3,157,475
Operating Segment | Other | Other segments
Segment Reporting Information
Net sales		658
Operating Segment | Other | U.S.
Segment Reporting Information
Net sales	352,329	297,121
Operating Segment | Other | Non-U.S.
Segment Reporting Information
Net sales	27,820	679
Eliminations
Segment Reporting Information
Net sales	(703,305)	(733,526)
Operating income (loss)	1,580	(5,443)
Income (loss) before income taxes	1,224	(5,786)
Assets	(149,990)
Eliminations | Other segments
Segment Reporting Information
Net sales	$ (703,305)	$ (733,526)