Commitments and Contingencies Warranty Account Activity (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011
WarrantiesActivity [Line Items]
Beginning balance	$ 79,536	$ 51,283
New product warranties	2,129	1,883
Other changes/adjustments to warranties	5,831	9,012
Claims activity	(11,320)	(4,447)
Effect of change in exchange rates	1,075	1,432
Ending balance	77,251	59,163
Less: current portion of warranty	48,235	26,260	52,588
Long-term warranty	$ 29,016	$ 32,903

Represents the aggregate decrease in the liability related to payments to satisfy claims for product warranties.

No definition available.

Name:	itri_ClaimsActivity
Namespace Prefix:	itri_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Carrying value as of the balance sheet date of obligations incurred through that date and payable for estimated warranty claims based on historical and projected product performance trends and costs. For classified balance sheets, represents the current portion of the liabilities (due within one year or within the normal operating cycle, if longer).

+ References

No definition available.

+ Details

Name:	itri_CurrentPortionOfWarranty
Namespace Prefix:	itri_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Total Increase or Decrease in the warranty liability due to currency translation.

+ References

No definition available.

+ Details

Name:	itri_EffectOfChangeInExchangeRatesWarranty
Namespace Prefix:	itri_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	itri_WarrantiesactivityLineItems
Namespace Prefix:	itri_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Carrying value as of the balance sheet date of obligations incurred through that date and payable for estimated warranty claims based on historical and projected product performance trends and costs.

+ References

No definition available.

+ Details

Name:	itri_WarrantyAccrual
Namespace Prefix:	itri_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the aggregate Increase or Decrease in the liability during the reporting period for accruals related to preexisting product warranties (including adjustments for changes in estimates).

+ References

No definition available.

+ Details

Name:	itri_WarrantyChangesAndAdjustments
Namespace Prefix:	itri_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Carrying value as of the balance sheet date of obligations incurred through that date and due after one year for estimated warranty claims based on historical and projected product performance trends and costs.

+ References

No definition available.

+ Details

Name:	itri_WarrantyNoncurrent
Namespace Prefix:	itri_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the aggregate increase in the liability for accruals related to standard product warranties issued during the reporting period. Does not include any increase in the liability for accruals related to extended product warranties.

+ References

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

-Publisher FASB

-Name FASB Interpretation (FIN)

-Number 45

-Paragraph 14

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 50

-Paragraph 8

-Subparagraph ((c)(3))

-URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12565-110249

+ Details

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