Segment Information - Results (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information
Total net sales	$ 18,795,316	$ 22,260,774	$ 18,408,850
Operating income (loss)	3,151,181	5,091,822	4,301,105
Income (loss) before income taxes	3,218,943	5,021,069	4,209,070
Depreciation and amortization	437,804	384,202	347,653
Capital expenditures	1,657,905	908,902	1,006,239
Assets	14,908,420	14,159,984
U.S.
Segment Reporting Information
Total net sales	16,967,684	20,851,771	17,290,933
Non-U.S.
Segment Reporting Information
Total net sales	1,827,632	1,409,003	1,117,917
Operating Segment | Steel Operations
Segment Reporting Information
Total net sales	13,067,622	15,100,996	14,023,133
Operating income (loss)	1,881,600	3,092,689	4,358,300
Income (loss) before income taxes	1,888,611	3,057,446	4,327,032
Depreciation and amortization	331,225	295,468	263,125
Capital expenditures	453,955	613,678	940,838
Assets	8,650,450	8,616,142
Operating Segment | Steel Operations | Other segments
Segment Reporting Information
Total net sales	427,071	537,647	823,991
Operating Segment | Steel Operations | U.S.
Segment Reporting Information
Total net sales	11,603,139	13,783,666	12,618,917
Operating Segment | Steel Operations | Non-U.S.
Segment Reporting Information
Total net sales	1,037,412	779,683	580,225
Operating Segment | Metals Recycling Operations
Segment Reporting Information
Total net sales	4,360,127	4,395,668	4,590,121
Operating income (loss)	88,654	116,497	181,986
Income (loss) before income taxes	105,797	117,034	181,579
Depreciation and amortization	70,705	53,934	55,620
Capital expenditures	190,864	68,690	46,360
Assets	1,458,500	1,320,871
Operating Segment | Metals Recycling Operations | Other segments
Segment Reporting Information
Total net sales	2,175,470	2,230,928	2,406,649
Operating Segment | Metals Recycling Operations | U.S.
Segment Reporting Information
Total net sales	1,401,341	1,545,379	1,658,843
Operating Segment | Metals Recycling Operations | Non-U.S.
Segment Reporting Information
Total net sales	783,316	619,361	524,629
Operating Segment | Steel Fabrication Operations
Segment Reporting Information
Total net sales	2,806,777	4,257,207	1,764,710
Operating income (loss)	1,593,261	2,424,655	365,250
Income (loss) before income taxes	1,593,275	2,417,752	362,473
Depreciation and amortization	9,787	9,727	9,961
Capital expenditures	22,044	17,519	12,939
Assets	790,399	1,349,138
Operating Segment | Steel Fabrication Operations | Other segments
Segment Reporting Information
Total net sales	7,843	11,221	3,063
Operating Segment | Steel Fabrication Operations | U.S.
Segment Reporting Information
Total net sales	2,798,262	4,245,803	1,761,078
Operating Segment | Steel Fabrication Operations | Non-U.S.
Segment Reporting Information
Total net sales	672	183	569
Operating Segment | Aluminum Operations
Segment Reporting Information
Operating income (loss)	(23,773)	(2,355)
Income (loss) before income taxes	(23,600)	(2,341)
Depreciation and amortization	15	44
Capital expenditures	962,778	185,082
Assets	1,320,224	186,254
Operating Segment | Other
Segment Reporting Information
Total net sales	1,171,901	1,287,980	1,266,971
Operating income (loss)	(394,577)	(594,045)	(549,537)
Income (loss) before income taxes	(349,626)	(621,813)	(605,753)
Depreciation and amortization	26,072	25,029	18,947
Capital expenditures	28,264	23,933	6,102
Assets	3,248,822	2,813,020
Operating Segment | Other | Other segments
Segment Reporting Information
Total net sales	727	1,281	2,382
Operating Segment | Other | U.S.
Segment Reporting Information
Total net sales	1,164,942	1,276,923	1,252,095
Operating Segment | Other | Non-U.S.
Segment Reporting Information
Total net sales	6,232	9,776	12,494
Eliminations
Segment Reporting Information
Total net sales	(2,611,111)	(2,781,077)	(3,236,085)
Operating income (loss)	6,016	54,381	(54,894)
Income (loss) before income taxes	4,486	52,991	(56,261)
Assets	(559,975)	(125,441)
Eliminations | Other segments
Segment Reporting Information
Total net sales	$ (2,611,111)	$ (2,781,077)	$ (3,236,085)