EARNINGS PER SHARE (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2012	Mar. 26, 2011
Basic EPS
Net earnings attributable to Valmont Industries, Inc, basic	$ 52,325	$ 25,609
Shares outstanding basic (in shares)	26,396	26,271
Per share amount basic (in dollars per share)	$ 1.98	$ 0.98
Dilutive Effect of Stock Options
Dilutive effect of stock options number of shares	282	266
Dilutive effect of stock options (in dollars per share)	$ (0.02)	$ (0.01)
Diluted EPS
Net earnings attributable to Valmont Industries, Inc, diluted	$ 52,325	$ 25,609
Shares outstanding dilutive (in shares)	26,678	26,537
Per share amount diluted (in dollars per share)	$ 1.96	$ 0.97
Antidilutive Securities
Outstanding stock options with exercise prices exceeding the market price of common stock, excluded from the computation of diluted earnings per share (in shares)		8,962

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