EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 25, 2022	Jun. 26, 2021	Jun. 25, 2022	Jun. 26, 2021
Basic EPS
Net earnings attributable to Valmont Industries, Inc.	$ 76,108	$ 62,110	$ 138,419	$ 117,124
Weighted average shares outstanding (in shares)	21,313,000	21,193,000	21,296,000	21,186,000
Per share amount basic (in dollars per share)	$ 3.57	$ 2.93	$ 6.50	$ 5.53
Dilutive Effect of Stock Options
Dilutive Effect of Stock Options	$ 0	$ 0	$ 0	$ 0
Dilutive effect of stock options number of shares (in shares)	228,000	276,000	220,000	263,000
Dilutive effect of stock options (in dollars per share)	$ (0.04)	$ (0.04)	$ (0.07)	$ (0.07)
Diluted EPS
Diluted EPS	$ 76,108	$ 62,110	$ 138,419	$ 117,124
Shares outstanding dilutive (in shares)	21,541,000	21,469,000	21,516,000	21,449,000
Per share amount diluted (in dollars per share)	$ 3.53	$ 2.89	$ 6.43	$ 5.46
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)			47,223	0