v2.3.0.15

Summary of Significant Accounting Policies Basis of Consolidation Policy Additional Information (Details)	9 Months Ended
	Sep. 30, 2011
Ownership Interest to be Held for Consolidation [Line Items]
Ownership Interest To Use Cost Method	20.00%
Maximum [Member]
Ownership Interest to be Held for Consolidation [Line Items]
Ownership Interest to be Held for Consolidation	50.00%
Minimum [Member]
Ownership Interest to be Held for Consolidation [Line Items]
Ownership Interest To Use Equity Method	50.00%

X

- Definition

Ownership Interest to be Held for Consolidation

+ Details

Name:	itri_OwnershipInterestToBeHeldForConsolidation
Namespace Prefix:	itri
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Ownership Interest to be Held for Consolidation [Line Items]

+ Details

Name:	itri_OwnershipInterestToBeHeldForConsolidationLineItems
Namespace Prefix:	itri
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Entities in which the company has less than 20% investment and where they do not excercise significant influence are accounted for under the cost method.

+ Details

Name:	itri_OwnershipInterestToUseCostMethod
Namespace Prefix:	itri
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The equity method of accounting is used for entities in which the company has a 50% or less invesment and exercises significant influence.

+ Details

Name:	itri_OwnershipInterestToUseEquityMethod
Namespace Prefix:	itri
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration