CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Net sales
Unrelated parties	$ 2,523,279	$ 3,220,891	$ 8,104,129	$ 8,902,025
Related parties	3,566	2,656	10,666	15,922
Total net sales	2,526,845	3,223,547	8,114,795	8,917,947
Costs of goods sold	2,167,006	2,537,466	6,900,220	7,116,368
Gross profit	359,839	686,081	1,214,575	1,801,579
Selling, general and administrative expenses	107,242	102,614	324,530	310,076
Profit sharing	17,848	45,304	64,396	114,301
Amortization of intangible assets	6,704	6,591	20,730	20,346
Operating income	228,045	531,572	804,919	1,356,856
Interest expense, net of capitalized interest	31,339	31,560	94,782	94,968
Other income, net	(4,545)	(7,103)	(15,137)	(16,601)
Income before income taxes	201,251	507,115	725,274	1,278,489
Income tax expense	48,643	109,209	171,093	292,536
Net income	152,608	397,906	554,181	985,953
Net (income) loss attributable to noncontrolling interests	(1,560)	469	(4,503)	2,422
Net income attributable to Steel Dynamics, Inc.	$ 151,048	$ 398,375	$ 549,678	$ 988,375
Basic earnings per share attributable to Steel Dynamics, Inc. stockholders	$ 0.69	$ 1.70	$ 2.49	$ 4.20
Weighted average common shares outstanding (in shares)	217,873	234,208	221,145	235,483
Diluted earnings per share attributable to Steel Dynamics, Inc. stockholders, including the effect of assumed conversions when dilutive (in dollars per share)	$ 0.69	$ 1.69	$ 2.47	$ 4.17
Weighted average common shares and share equivalents outstanding (in shares)	219,109	235,649	222,197	236,772
Dividends declared per share (in dollars per share)	$ 0.2400	$ 0.1875	$ 0.7200	$ 0.5625