EARNINGS PER SHARE (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013
Basic EPS
Net earnings attributable to Valmont Industries, Inc, basic	$ 23,559	$ 56,489	$ 143,515	$ 223,621
Shares outstanding, basic	25,287	26,665	26,208	26,632
Per share amount, basic (in dollars per share)	$ 0.93	$ 2.12	$ 5.48	$ 8.40
Dilutive Effect of Stock Options
Dilutive effect of stock options number of shares	226	254	231	264
Dilutive effect of stock options (in dollars per share)	$ (0.01)	$ (0.02)	$ (0.05)	$ (0.09)
Diluted EPS
Net earnings attributable to Valmont Industries, Inc, diluted	$ 23,559	$ 56,489	$ 143,515	$ 223,621
Shares outstanding dilutive	25,513	26,919	26,439	26,896
Per share amount, diluted (in dollars per share)	$ 0.92	$ 2.10	$ 5.43	$ 8.31
Antidilutive Securities
Outstanding stock options with exercise prices exceeding the market price of common stock (in shares)	273,170		273,170	1,172