CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Net sales
Unrelated parties	$ 1,978,984	$ 1,945,983	$ 3,676,988	$ 3,949,956
Related parties	44,918	59,024	88,215	102,486
Total net sales	2,023,902	2,005,007	3,765,203	4,052,442
Costs of goods sold	1,643,519	1,833,264	3,148,784	3,693,657
Gross profit	380,383	171,743	616,419	358,785
Selling, general and administrative expenses	96,853	82,660	184,383	159,010
Profit sharing	20,176	5,031	29,467	9,629
Amortization of intangible assets	7,232	6,493	14,482	12,816
Operating income	256,122	77,559	388,087	177,330
Interest expense, net of capitalized interest	36,646	37,163	73,689	80,250
Other expense (income), net	(1,818)	(1,212)	(3,610)	14,980
Income before income taxes	221,294	41,608	318,008	82,100
Income taxes	80,851	16,283	116,247	29,821
Net income	140,443	25,325	201,761	52,279
Net loss attributable to noncontrolling interests	1,526	6,225	2,945	10,032
Net income attributable to Steel Dynamics, Inc.	$ 141,969	$ 31,550	$ 204,706	$ 62,311
Basic earnings per share attributable to Steel Dynamics, Inc. stockholders	$ 0.58	$ 0.13	$ 0.84	$ 0.26
Weighted average common shares outstanding - basic (in shares)	243,655	241,900	243,429	241,718
Diluted earnings per share attributable to Steel Dynamics, Inc. stockholders, including the effect of assumed conversions when dilutive (in dollars per share)	$ 0.58	$ 0.13	$ 0.84	$ 0.26
Weighted average common shares and share equivalents outstanding (in shares)	245,392	243,491	245,000	243,179
Dividends declared per share (in dollars per share)	$ 0.1400	$ 0.1375	$ 0.2750	$ 0.2750