v2.4.1.9

Stock-Based Compensation Stock-Based Compensation Expense and Related Tax Benefit (Details) (USD $) In Thousands, unless otherwise specified | 12 Months Ended
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Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Stock options | $ 2,333 us-gaap_StockOptionPlanExpense | $ 2,074 us-gaap_StockOptionPlanExpense | $ 1,547 us-gaap_StockOptionPlanExpense
Restricted stock units | 14,591 us-gaap_RestrictedStockExpense | 15,475 us-gaap_RestrictedStockExpense | 16,583 us-gaap_RestrictedStockExpense
Unrestricted stock awards | 936 itri_UnrestrictedStockAwardsCompensationExpense | 811 itri_UnrestrictedStockAwardsCompensationExpense | 769 itri_UnrestrictedStockAwardsCompensationExpense
ESPP | 0 itri_EmployeeStockPurchasePlanCompensationExpense | 490 itri_EmployeeStockPurchasePlanCompensationExpense | 613 itri_EmployeeStockPurchasePlanCompensationExpense
Total stock-based compensation | 17,860 us-gaap_ShareBasedCompensation | 18,850 us-gaap_ShareBasedCompensation | 19,512 us-gaap_ShareBasedCompensation
Related tax benefit | $ 4,994 us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense | $ 5,152 us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense | $ 5,377 us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense

X
- Definition The noncash expense that represents the cost of awards granted to employees as compensation under the employee stock purchase plan. + References No definition available. + Details
Name: | itri_EmployeeStockPurchasePlanCompensationExpense
Namespace Prefix: | itri_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The noncash expense that represents the cost of unrestricted stock distributed to board of directors as a portion of their compensation. + References No definition available. + Details
Name: | itri_UnrestrictedStockAwardsCompensationExpense
Namespace Prefix: | itri_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1)(i) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
Name: | us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The noncash expense that represents the cost of restricted stock or unit distributed to employees as compensation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585 + Details
Name: | us-gaap_RestrictedStockExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock or unit options, amortization of restricted stock or units, and adjustment for officers' compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585 + Details
Name: | us-gaap_ShareBasedCompensation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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

X
- Definition The noncash expense that accounts for the value of stock or unit options distributed to employees as compensation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585 + Details
Name: | us-gaap_StockOptionPlanExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration