Segment Information - Results (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Segment Reporting Information
Net sales	$ 4,587,057	$ 5,651,707	$ 14,561,893	$ 17,434,487
Operating income (loss)	733,550	1,219,844	2,632,645	4,332,774
Income (loss) before income taxes	754,599	1,208,472	2,676,704	4,262,619
Depreciation and amortization	107,418	98,714	326,082	281,961
Capital expenditures	558,361	241,229	1,142,960	564,701
Assets	14,928,956		14,928,956		$ 14,159,984
U.S.
Segment Reporting Information
Net sales	4,116,294	5,294,765	13,098,688	16,364,996
Non-U.S.
Segment Reporting Information
Net sales	470,763	356,942	1,463,205	1,069,491
Operating Segment | Steel Operations
Segment Reporting Information
Net sales	3,261,067	3,873,544	10,054,931	12,051,813
Operating income (loss)	470,335	654,677	1,514,741	2,920,412
Income (loss) before income taxes	472,051	646,426	1,518,438	2,885,437
Depreciation and amortization	81,517	76,453	246,583	217,097
Capital expenditures	111,843	131,753	334,188	403,807
Assets	8,665,334		8,665,334
Operating Segment | Steel Operations | Other segments
Segment Reporting Information
Net sales	124,622	152,719	460,156	426,470
Operating Segment | Steel Operations | U.S.
Segment Reporting Information
Net sales	2,904,204	3,512,202	8,874,866	11,015,050
Operating Segment | Steel Operations | Non-U.S.
Segment Reporting Information
Net sales	232,241	208,623	719,909	610,293
Operating Segment | Metals Recycling Operations
Segment Reporting Information
Net sales	1,052,305	984,625	3,382,357	3,483,824
Operating income (loss)	13,981	6,735	86,674	106,138
Income (loss) before income taxes	15,319	5,415	99,093	104,591
Depreciation and amortization	17,195	12,932	52,321	39,207
Capital expenditures	83,858	11,137	128,814	37,893
Assets	1,475,378		1,475,378
Operating Segment | Metals Recycling Operations | Other segments
Segment Reporting Information
Net sales	531,559	512,559	1,685,770	1,782,398
Operating Segment | Metals Recycling Operations | U.S.
Segment Reporting Information
Net sales	334,922	328,187	1,086,286	1,252,323
Operating Segment | Metals Recycling Operations | Non-U.S.
Segment Reporting Information
Net sales	185,824	143,879	610,301	449,103
Operating Segment | Steel Fabrication Operations
Segment Reporting Information
Net sales	633,207	1,145,826	2,281,609	3,166,124
Operating income (loss)	330,020	676,726	1,343,372	1,742,792
Income (loss) before income taxes	329,554	674,718	1,343,173	1,736,680
Depreciation and amortization	2,448	2,454	7,201	7,317
Capital expenditures	5,581	4,975	17,215	13,234
Assets	972,462		972,462
Operating Segment | Steel Fabrication Operations | Other segments
Segment Reporting Information
Net sales	3,023	5,554	3,248	10,117
Operating Segment | Steel Fabrication Operations | U.S.
Segment Reporting Information
Net sales	630,045	1,140,272	2,278,121	3,155,824
Operating Segment | Steel Fabrication Operations | Non-U.S.
Segment Reporting Information
Net sales	139		240	183
Operating Segment | Other
Segment Reporting Information
Net sales	299,854	318,544	992,611	952,741
Operating income (loss)	(95,638)	(137,160)	(315,389)	(473,889)
Income (loss) before income taxes	(76,801)	(136,613)	(286,104)	(500,385)
Depreciation and amortization	6,258	6,875	19,977	18,340
Capital expenditures	357,079	93,364	662,743	109,767
Assets	3,947,177		3,947,177
Operating Segment | Other | Other segments
Segment Reporting Information
Net sales	172		441	1,030
Operating Segment | Other | U.S.
Segment Reporting Information
Net sales	247,123	314,104	859,415	941,799
Operating Segment | Other | Non-U.S.
Segment Reporting Information
Net sales	52,559	4,440	132,755	9,912
Eliminations
Segment Reporting Information
Net sales	(659,376)	(670,832)	(2,149,615)	(2,220,015)
Operating income (loss)	14,852	18,866	3,247	37,321
Income (loss) before income taxes	14,476	18,526	2,104	36,296
Assets	(131,395)		(131,395)
Eliminations | Other segments
Segment Reporting Information
Net sales	$ (659,376)	$ (670,832)	$ (2,149,615)	$ (2,220,015)