EARNINGS PER SHARE (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 25, 2011	Jun. 30, 2012	Jun. 25, 2011
Basic EPS
Net earnings attributable to Valmont Industries, Inc, basic	$ 59,980	$ 45,827	$ 112,305	$ 71,436
Shares outstanding basic	26,467	26,333	26,432	26,302
Per share amount basic (in dollars per share)	$ 2.27	$ 1.74	$ 4.25	$ 2.72
Dilutive Effect of Stock Options
Dilutive effect of stock options number of shares	291	252	286	259
Dilutive effect of stock options (in dollars per share)	$ (0.03)	$ (0.02)	$ (0.05)	$ (0.03)
Diluted EPS
Net earnings attributable to Valmont Industries, Inc, diluted	$ 59,980	$ 45,827	$ 112,305	$ 71,436
Shares outstanding dilutive	26,758	26,585	26,718	26,561
Per share amount diluted (in dollars per share)	$ 2.24	$ 1.72	$ 4.20	$ 2.69
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)				16,828