EARNINGS PER SHARE (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Basic EPS
Net earnings attributable to Valmont Industries, Inc, basic	$ 56,489	$ 56,731	$ 223,621	$ 169,036
Shares outstanding basic	26,665,000	26,502,000	26,632,000	26,455,000
Per share amount basic (in dollars per share)	$ 2.12	$ 2.14	$ 8.40	$ 6.39
Dilutive Effect of Stock Options
Dilutive effect of stock options number of shares	254,000	304,000	264,000	293,000
Dilutive effect of stock options (in dollars per share)	$ (0.02)	$ (0.02)	$ (0.09)	$ (0.07)
Diluted EPS
Net earnings attributable to Valmont Industries, Inc, diluted	$ 56,489	$ 56,731	$ 223,621	$ 169,036
Shares outstanding dilutive	26,919,000	26,806,000	26,896,000	26,748,000
Per share amount diluted (in dollars per share)	$ 2.10	$ 2.12	$ 8.31	$ 6.32
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)	1,172		1,172	0