CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Per Share data	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Net sales
Unrelated parties	$ 1,976,296	$ 1,520,346	$ 5,922,243	$ 4,584,285
Related parties	67,159	63,818	216,912	188,468
Total net sales	2,043,455	1,584,164	6,139,155	4,772,753
Costs of goods sold	1,844,212	1,444,632	5,367,772	4,230,755
Gross profit	199,243	139,532	771,383	541,998
Selling, general and administrative expenses	72,876	54,679	201,648	167,796
Profit sharing	7,428	4,562	37,085	21,833
Amortization of intangible assets	10,154	11,291	30,320	34,437
Total selling, general and administrative expenses	90,458	70,532	269,053	224,066
Operating income	108,785	69,000	502,330	317,932
Interest expense, net of capitalized interest	44,702	44,286	132,860	125,249
Other income, net	(3,523)	(6,215)	(13,835)	(12,817)
Income before income taxes	67,606	30,929	383,305	205,500
Income taxes	27,749	15,574	143,392	79,959
Net income	39,857	15,355	239,913	125,541
Net loss attributable to noncontrolling interests	3,447	3,386	8,004	7,376
Net income attributable to Steel Dynamics, Inc.	$ 43,304	$ 18,741	$ 247,917	$ 132,917
Basic earnings per share attributable to Steel Dynamics, Inc. stockholders (in dollars per share)	$ 0.20	$ 0.09	$ 1.14	$ 0.61
Weighted average common shares outstanding (in shares)	218,674	216,881	218,389	216,600
Diluted earnings per share attributable to Steel Dynamics, Inc. stockholders, including the effect of assumed conversions when dilutive (in dollars per share)	$ 0.19	$ 0.09	$ 1.08	$ 0.60
Weighted average common shares and share equivalents outstanding (in shares)	235,759	234,543	236,083	234,601
Dividends declared per share (in dollars per share)	$ 0.10	$ 0.075	$ 0.30	$ 0.225