Document and Entity Information - shares	6 Months Ended
	Jun. 27, 2015	Jul. 22, 2015
Document and Entity Information
Entity Registrant Name	VALMONT INDUSTRIES INC
Entity Central Index Key	0000102729
Document Type	10-Q
Document Period End Date	Jun. 27, 2015
Amendment Flag	false
Current Fiscal Year End Date	--12-26
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		23,248,776
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q2