Amount awarded to other party in judgment or settlement of litigation.

No definition available.

Name:	us-gaap_LitigationSettlementAmountAwardedToOtherParty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 275
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482861/275-10-50-9

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-4

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-9

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 720
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483359/720-20-50-1

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Topic 460
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 27
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482395/460-10-55-27

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-9

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-4

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 460
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482425/460-10-50-3

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-1

+ Details

Name:	us-gaap_LossContingenciesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of loss contingency liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-1

Reference 2: http://www.xbrl.org/2003/role/recommendedDisclosureRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-10

+ Details

Name:	us-gaap_LossContingencyAccrualAtCarryingValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Expected tariff rate.

+ References

No definition available.

+ Details

Name:	vmi_ExpectedTariffRate
Namespace Prefix:	vmi_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Expected maximum tariff rate on full value.

+ References

No definition available.

+ Details

Name:	vmi_MaximumTariffRateOnFullValue
Namespace Prefix:	vmi_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of customs and border protection inquiries.

+ References

No definition available.

+ Details

Name:	vmi_NumberOfCustomsAndBorderProtectionInquiries
Namespace Prefix:	vmi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of customs and border protection inquiries not responded.

+ References

No definition available.

+ Details

Name:	vmi_NumberOfCustomsAndBorderProtectionInquiriesNotResponded
Namespace Prefix:	vmi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Minimum percentage of content subject to higher tariff rates.

+ References

No definition available.

+ Details

Name:	vmi_PercentageOfContentSubjectToHigherTariffRates
Namespace Prefix:	vmi_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Indicates the Section 232 tariff rate applied to steel products that meet U.S. steel sourcing requirements, resulting in application of the reduced ad valorem rate.

+ References

No definition available.

+ Details

Name:	vmi_Section232PreferentialRate
Namespace Prefix:	vmi_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_LitigationCaseAxis=vmi_BrazilianCaseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_LitigationCaseAxis=vmi_UsCustomsAndBorderProtectionInquiryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

CONTINGENCIES (Details) R$ in Thousands, $ in Thousands		3 Months Ended
CONTINGENCIES (Details) R$ in Thousands, $ in Thousands	Apr. 02, 2026	Mar. 28, 2026 BRL (R$) item	Mar. 28, 2026 USD ($) item	Dec. 27, 2025 USD ($)
Subsequent Event [Member]
CONTINGENCIES
Section 232 preferential rate	10.00%
Minimum percentage of content subject to higher tariff rates	95.00%
Maximum tariff rate on full value	50.00%
Expected tariff rate	10.00%
Brazilian case
CONTINGENCIES
Litigation settlement amount		R$ 105,000	$ 20,036
Accrued amount \| $			$ 24,104	$ 24,165
U.S. Customs and Border Protection Inquiry
CONTINGENCIES
Number of CBP inquiries		2	2
Number of CBP inquiries not responded		1	1