EARNINGS PER SHARE - Schedule of Reconciliation of Basic and Diluted Earnings Per Share (EPS) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 25, 2021	Dec. 26, 2020
Basic EPS
Net earnings attributable to Valmont Industries, Inc.	$ 250,863	$ 195,630	$ 140,693
Shares outstanding basic (in shares)	21,311	21,193	21,315
Per share amount basic (in dollars per share)	$ 11.77	$ 9.23	$ 6.60
Dilutive Effect of Stock Options
Dilutive Effect of Stock Options	$ 0	$ 0	$ 0
Dilutive effect of stock options number of shares (in shares)	269	300	110
Dilutive effect of stock options (in dollars per share)	$ (0.15)	$ (0.13)	$ (0.03)
Diluted EPS
Diluted EPS	$ 250,863	$ 195,630	$ 140,693
Shares outstanding dilutive (in shares)	21,580	21,493	21,425
Per share amount diluted (in dollars per share)	$ 11.62	$ 9.10	$ 6.57