v2.4.0.6

Segment Information Major Customers (Details) | 3 Months Ended
--- | ---
Mar. 31, 2013 | Mar. 31, 2012
Revenue, Major Customer [Line Items] |  |
Segment Reporting, Disclosure of Major Customers | 0 | 1
Energy Operating Segment [Member] |  |
Revenue, Major Customer [Line Items] |  |
Major Customers Percentage Revenue Threshold | 10.00% | 10.00%
Number Of Major Customers | 0 | 2
Entity-Wide Revenue, Major Customer, Percentage |  | 11.00%
Water Operating Segment [Member] |  |
Revenue, Major Customer [Line Items] |  |
Major Customers Percentage Revenue Threshold | 10.00% | 10.00%
Number Of Major Customers | 0 | 0

X
- Definition Represents number of customers with revenues greater than 10% of total company and/or segment revenues for the periods presented. + References No definition available. + Details
Name: | itri_NumberOfMajorCustomers
Namespace Prefix: | itri_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage represents the concentration risk threshold for customer revenues as a percent of total company revenues and/or total segment revenues. Customer with revenues greater than this percentage threshold of total company revenues and/or segment revenues must be stated. + References No definition available. + Details
Name: | itri_PercentageOfRevenuesByMajorCustomers
Namespace Prefix: | itri_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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

X
- Definition Percentage of revenue generated from a single external customer that accounts for 10 percent or more of an entity's revenues. + References No definition available. + Details
Name: | us-gaap_EntityWideRevenueMajorCustomerPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Disclosure of the extent of enterprise reliance on its major customers. For example, includes revenues from transactions with a single external customer amounting to 10 percent or more of the entity's revenues, the total amount of revenues from each such customer, and the identity of the segment or segments reporting the revenues. A group of entities that the entity knows to be under common control generally will be considered a single customer for inclusion in this item. The federal government, a state government, a local government (for example, a county or municipality), or a foreign government each will generally be considered as a single customer for inclusion in this item. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 131 -Paragraph 39 -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. + Details
Name: | us-gaap_SegmentReportingDisclosureOfMajorCustomers
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration