EARNINGS PER SHARE - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 25, 2021	Dec. 26, 2020
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Loss from divestiture of offshore wind energy structures business	$ (33,273)
Associated tax benefit	0
Impairment of goodwill & intangible assets	27,900
Restructuring expenses	$ 23,149
Outstanding stock options with exercise prices exceeding the market price of common stock, excluded from the computation of diluted earnings per share (in shares)	40,564	47,223	0
Valmont SM, Offshore Wind Business [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Associated tax benefit	$ 0
Valuation allowance		$ 5,076
Valuation allowance (in dollars per share)		$ 0.24
Offshore and Other Complex Steel Structures | Valmont SM, Offshore Wind Business [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Loss from divestiture of offshore wind energy structures business	$ 33,273
Loss from divestiture of offshore wind energy structures business, per share	$ 1.54
Goodwill And Indefinite-lived Intangible Assets
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Impairment of goodwill & intangible assets			$ 16,220
Impairment of goodwill and intangible assets (in dollars per share)			$ 0.76
long | Valmont SM, Offshore Wind Business [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Impairment of goodwill & intangible assets		$ 21,678
Impairment of goodwill and intangible assets (in dollars per share)		$ 1.01
2020 Restructuring Plan
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Restructuring expenses			$ 17,324
Restructuring expenses, (in dollars per share)			$ 0.81