EARNINGS PER SHARE (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 25, 2016	Jun. 27, 2015	Jun. 25, 2016	Jun. 27, 2015
Basic EPS
Net earnings attributable to Valmont Industries, Inc.	$ 42,026,000	$ 27,873,000	$ 74,995,000	$ 58,612,000
Shares outstanding basic (in shares)	22,602,000	23,336,000	22,651,000	23,602,000
Per share amount basic (in dollars per share)	$ 1.86	$ 1.19	$ 3.31	$ 2.48
Dilutive Effect of Stock Options
Dilutive Effect of Stock Options	$ 0	$ 0	$ 0	$ 0
Dilutive effect of stock options number of shares (in shares)	147,000	114,000	131,000	114,000
Dilutive effect of stock options (in dollars per share)	$ (0.01)	$ 0.00	$ (0.02)	$ (0.01)
Diluted EPS
Diluted EPS	$ 42,026,000	$ 27,873,000	$ 74,995,000	$ 58,612,000
Shares outstanding dilutive (in shares)	22,749,000	23,450,000	22,782,000	23,716,000
Per share amount diluted (in dollars per share)	$ 1.85	$ 1.19	$ 3.29	$ 2.47
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)			381,973	452,459