EARNINGS PER SHARE (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 29, 2012	Sep. 24, 2011	Sep. 29, 2012	Sep. 24, 2011
Basic EPS
Net earnings attributable to Valmont Industries, Inc, basic	$ 56,731	$ 42,141	$ 169,036	$ 113,577
Shares outstanding basic	26,502	26,351	26,455	26,318
Per share amount basic (in dollars per share)	$ 2.14	$ 1.60	$ 6.39	$ 4.32
Dilutive Effect of Stock Options
Dilutive effect of stock options number of shares	304	228	293	249
Dilutive effect of stock options (in dollars per share)	$ (0.02)	$ (0.01)	$ (0.07)	$ (0.04)
Diluted EPS
Net earnings attributable to Valmont Industries, Inc, diluted	$ 56,731	$ 42,141	$ 169,036	$ 113,577
Shares outstanding dilutive	26,806	26,579	26,748	26,567
Per share amount diluted (in dollars per share)	$ 2.12	$ 1.59	$ 6.32	$ 4.28
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)		218,007		218,007

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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