Cover Page - USD ($)	12 Months Ended
	Dec. 30, 2023	Feb. 23, 2024	Jul. 01, 2023
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 30, 2023
Current Fiscal Year End Date	--12-30
Document Transition Report	false
Entity File Number	1-31429
Entity Registrant Name	Valmont Industries, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-0351813
Entity Address, Address Line One	15000 Valmont Plaza,
Entity Address, City or Town	Omaha
Entity Address, State or Province	NE
Entity Address, Postal Zip Code	68154
City Area Code	402
Local Phone Number	963-1000
Title of 12(b) Security	Common Stock, $1.00 par value
Trading Symbol	VMI
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Smaller Reporting Company	false
Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction [Flag]	true
Document Financial Statement Restatement Recovery Analysis [Flag]	false
Shell Company	false
Entity Common Stock, Shares Outstanding		20,216,385
Entity Public Float			$ 5,766,436,565
Entity Central Index Key	0000102729
Amendment Flag	false
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Auditor Location	Omaha, Nebraska
Auditor Name	DELOITTE & TOUCHE LLP
Auditor Firm ID	34