EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 26, 2022	Mar. 27, 2021
Basic EPS
Net earnings attributable to Valmont Industries, Inc.	$ 62,311	$ 55,014
Weighted average shares outstanding (in shares)	21,279,000	21,179,000
Per share amount basic (in dollars per share)	$ 2.93	$ 2.60
Dilutive Effect of Stock Options
Dilutive Effect of Stock Options	$ 0	$ 0
Dilutive effect of stock options number of shares (in shares)	213,000	250,000
Dilutive effect of stock options (in dollars per share)	$ (0.03)	$ (0.03)
Diluted EPS
Diluted EPS	$ 62,311	$ 55,014
Shares outstanding dilutive (in shares)	21,492,000	21,429,000
Per share amount diluted (in dollars per share)	$ 2.90	$ 2.57
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