Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

-Section 13

-Sentence Column B

+ Details

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Namespace Prefix:	invest_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 55

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=6584090&loc=d3e28878-108400

+ Details

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Face (par) amount of the original debt instrument that was repurchased.

+ References

No definition available.

+ Details

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

- Details

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

- Definition

Represents the amount of costs associated with refinancing of debt.

+ References

No definition available.

+ Details

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

- Definition

Represents the amount paid to counterparty to settle the interest rate derivative contract, designated as cash flow hedge.

+ References

No definition available.

+ Details

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Namespace Prefix:	vmi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the amount after tax of realized loss from accumulated other comprehensive income of accumulated gain (loss) realized from derivative instruments designated and qualifying as the effective portion of cash flow hedges and the entity's share of an equity investee's deferred hedging gain (loss).

+ References

No definition available.

+ Details

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Namespace Prefix:	vmi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details 4) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended					1 Months Ended			0 Months Ended
	Sep. 27, 2014	Sep. 27, 2014	Sep. 27, 2014 2044 Notes	Sep. 22, 2014 2044 Notes	Sep. 27, 2014 2054 Notes	Sep. 22, 2014 2054 Notes	Sep. 27, 2014 2020 Notes	Sep. 22, 2014 2020 Notes	Dec. 28, 2013 2020 Notes	Sep. 10, 2014 Interest rate contract Cash flow hedging	Jun. 28, 2014 Interest rate contract Cash flow hedging
Derivative Instrument
Aggregate principal amount				$ 250,000		$ 250,000	$ 250,000
Interest rate on notes (as a percent)			5.00%	5.00%	5.25%	5.25%	6.625%	6.625%	6.625%
Notional amount of derivative instrument											125,000
Payment to counterparty to settle the derivative contract										4,837
Repurchase amount through partial tender offer							199,800	199,800
Realized loss included in net earnings during the period							983
Costs associated with refinancing of debt	$ 38,705	$ 38,705					$ 983