CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Net sales
Unrelated parties	$ 2,319,663	$ 1,698,004
Related parties	48,553	43,297
Total net sales	2,368,216	1,741,301
Costs of goods sold	1,896,062	1,505,265
Gross profit	472,154	236,036
Selling, general and administrative expenses	102,933	87,530
Profit sharing	27,231	9,291
Amortization of intangible assets	7,424	7,250
Operating income	334,566	131,965
Interest expense, net of capitalized interest	33,973	37,043
Other expense (income), net	(3,659)	(1,792)
Income before income taxes	304,252	96,714
Income tax expense	105,586	35,396
Net income	198,666	61,318
Net loss attributable to noncontrolling interests	2,151	1,419
Net income attributable to Steel Dynamics, Inc.	$ 200,817	$ 62,737
Basic earnings per share attributable to Steel Dynamics, Inc. stockholders	$ 0.83	$ 0.26
Weighted average common shares outstanding - basic (in shares)	242,943	243,202
Diluted earnings per share attributable to Steel Dynamics, Inc. stockholders, including the effect of assumed conversions when dilutive (in dollars per share)	$ 0.82	$ 0.26
Weighted average common shares and share equivalents outstanding (in shares)	244,546	244,608
Dividends declared per share (in dollars per share)	$ 0.155	$ 0.140