CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Total net sales	$ 4,341,615	$ 4,587,057	$ 13,668,252	$ 14,561,893
Costs of goods sold	3,736,398	3,635,038	11,307,400	11,246,894
Gross profit	605,217	952,019	2,360,852	3,314,999
Selling, general and administrative expenses	167,692	145,896	487,215	431,414
Profit sharing	34,444	64,413	145,149	224,978
Amortization of intangible assets	7,644	8,160	22,953	25,962
Operating income	395,437	733,550	1,705,535	2,632,645
Interest expense, net of capitalized interest	17,071	18,415	41,768	61,689
Other (income) expense, net	(29,659)	(39,464)	(75,151)	(105,748)
Income before income taxes	408,025	754,599	1,738,918	2,676,704
Income tax expense	87,131	174,817	398,834	636,412
Net income	320,894	579,782	1,340,084	2,040,292
Net income attributable to noncontrolling interests	(3,092)	(2,587)	(10,243)	(13,680)
Net income attributable to Steel Dynamics, Inc.	$ 317,802	$ 577,195	$ 1,329,841	$ 2,026,612
Basic earnings per share attributable to Steel Dynamics, Inc. stockholders (in dollars per share)	$ 2.06	$ 3.49	$ 8.50	$ 12.04
Weighted average common shares outstanding (in shares)	154,061	165,170	156,528	168,259
Diluted earnings per share attributable to Steel Dynamics, Inc. stockholders, including the effect of assumed conversions when dilutive (in dollars per share)	$ 2.05	$ 3.47	$ 8.46	$ 11.98
Weighted average common shares and share equivalents outstanding (in shares)	154,810	166,105	157,248	169,150
Dividends declared per share (in dollars per share)	$ 0.46	$ 0.425	$ 1.38	$ 1.275
Unrelated parties
Total net sales	$ 4,162,651	$ 4,408,861	$ 13,103,464	$ 14,061,569
Related parties
Total net sales	$ 178,964	$ 178,196	$ 564,788	$ 500,324