Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

GOODWILL AND INTANGIBLE ASSETS - Narrative (Details)		3 Months Ended			12 Months Ended
GOODWILL AND INTANGIBLE ASSETS - Narrative (Details)	Aug. 28, 2021 USD ($)	Dec. 25, 2021 USD ($)	Sep. 25, 2021 USD ($)	Jun. 26, 2021 USD ($)	Dec. 26, 2020 USD ($) tradeName
Indefinite-lived Intangible Assets
Number of trade names impaired \| tradeName					2
Goodwill impairment			$ 0		$ 12,575,000
Access Systems
Indefinite-lived Intangible Assets
Goodwill impairment				$ 12,575,000
Trade Name
Indefinite-lived Intangible Assets
Impairment of intangible assets	$ 0				$ 3,900,000
Valmont SM
Indefinite-lived Intangible Assets
Impairment of intangible assets		$ 2,013,000