v2.4.1.9

Summary of Significant Accounting Policies Basis of Consolidation Policy Additional Information (Details) | 12 Months Ended
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Dec. 31, 2014
Maximum [Member] |
Basis of Consolidation [Abstract] |
Ownership Interest To Use Equity Method | 50.00%itri_OwnershipInterestToUseEquityMethod / us-gaap_RangeAxis = us-gaap_MaximumMember
Ownership Interest To Use Cost Method | 20.00%itri_OwnershipInterestToUseCostMethod / us-gaap_RangeAxis = us-gaap_MaximumMember
Minimum [Member] |
Basis of Consolidation [Abstract] |
Ownership Interest to be Held for Consolidation | 50.00%itri_OwnershipInterestToBeHeldForConsolidation / us-gaap_RangeAxis = us-gaap_MinimumMember
Noncontrolling Interests [Abstract] |
Ownership Interest to be Held for Consolidation | 50.00%itri_OwnershipInterestToBeHeldForConsolidation / us-gaap_RangeAxis = us-gaap_MinimumMember

X
- Details
Name: | itri_BasisofConsolidationAbstract
Namespace Prefix: | itri_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Ownership Interest to be Held for Consolidation + References No definition available. + Details
Name: | itri_OwnershipInterestToBeHeldForConsolidation
Namespace Prefix: | itri_
Data Type: | num:percentItemType
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. + References No definition available. + 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. + References No definition available. + Details
Name: | itri_OwnershipInterestToUseEquityMethod
Namespace Prefix: | itri_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_NoncontrollingInterestAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |