EARNINGS PER SHARE (Details 2) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended	3 Months Ended	12 Months Ended
Dec. 31, 2011 Delta Ltd.	Dec. 28, 2013 EMD	Dec. 28, 2013 EMD
Deconsolidation
After-tax loss on deconsolidation			$ 12,011
After-tax loss on deconsolidation (in dollars per share)			$ 0.45
Asset impairment loss related to deconsolidation		4,569
Asset impairment loss related to deconsolidation (in dollars per share)		$ 0.17
Income tax benefit of reorganization included in earnings	$ 66,026
Income tax benefit of reorganization included in earnings (in dollars per share)	$ 2.49

The amount of the gain (loss) recognized by the parent and included in its attributable portion of net income for the period due to deconsolidation of a subsidiary or derecognition of a group of assets. The gain (loss) recognized and included in the net income attributable to the parent for the period is generally computed as the difference between: (a) the aggregate of: (1) the fair value of any consideration received; (2) the fair value of any retained noncontrolling investment in the former subsidiary at the date the subsidiary was deconsolidated; and (3) the carrying amount of any noncontrolling interest in the former subsidiary (including any accumulated other comprehensive income attributable to the noncontrolling interest) at the date the subsidiary was deconsolidated and (b) the carrying amount of the former subsidiary's assets and liabilities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 50

-Paragraph 1B

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=18733093&loc=SL4582445-111684

+ Details

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

- Definition

Amount of tax expense or benefit on gain (loss), not previously recognized, resulting from the sale of a business component.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 10

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32672-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 20

-Section 45

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6892542&loc=d3e957-107759

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1361-107760

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 20

-Section 45

-Paragraph 2

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=18498875&loc=d3e38679-109324

+ Details

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

- Details

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

- Definition

Represents the amount of write-down of assets related to deconsolidation recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

+ References

No definition available.

+ Details

Name:	vmi_AssetImpairmentChargesRelatedToDeconsolidation
Namespace Prefix:	vmi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the per share amount related to asset impairment loss.

+ References

No definition available.

+ Details

Name:	vmi_BasicAndDilutedEarningsPerShareAssetImpairmentCharges
Namespace Prefix:	vmi_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the amount of gain (loss) per share, after tax expense or benefit.

+ References

No definition available.

+ Details

Name:	vmi_DeconsolidationGainOrLossAmountPerShare
Namespace Prefix:	vmi_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the per share amount of income tax benefit of reorganization included in earnings.

+ References

No definition available.

+ Details

Name:	vmi_DiscontinuedOperationTaxEffectOfIncomeLossFromDisposalOfDiscontinuedOperationPerShare
Namespace Prefix:	vmi_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration