EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 24, 2022	Sep. 25, 2021	Sep. 24, 2022	Sep. 25, 2021
Basic EPS
Net earnings attributable to Valmont Industries, Inc., Basic EPS	$ 72,112	$ 51,650	$ 210,531	$ 168,774
Weighted average shares outstanding, Basic EPS (in shares)	21,332,000	21,175,000	21,308,000	21,182,000
Per share amount, Basic EPS (in dollars per share)	$ 3.38	$ 2.44	$ 9.88	$ 7.97
Dilutive Effect of Stock Options
Weighted average shares outstanding, Dilutive Effect of Stock Options (in shares)	273,000	377,000	238,000	301,000
Per share amount, Dilutive effect of stock options (in dollars per share)	$ (0.04)	$ (0.04)	$ (0.11)	$ (0.11)
Diluted EPS
Net earnings attributable to Valmont Industries, Inc., Diluted EPS	$ 72,112	$ 51,650	$ 210,531	$ 168,774
Weighted average shares outstanding, Diluted EPS (in shares)	21,605,000	21,552,000	21,546,000	21,483,000
Per share amount, Diluted EPS (in dollars per share)	$ 3.34	$ 2.40	$ 9.77	$ 7.86
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)	0	0