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Defined Benefit Pension Plans Change in Benefit Obligation and Plan Assets (Details) (USD $)
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12 Months Ended | ||
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Dec. 31, 2014
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Dec. 31, 2013
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Dec. 31, 2012
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| Defined Benefit Plan Disclosure [Line Items] | |||
| Service cost | $ 3,559,000us-gaap_DefinedBenefitPlanServiceCost | $ 4,205,000us-gaap_DefinedBenefitPlanServiceCost | $ 2,700,000us-gaap_DefinedBenefitPlanServiceCost |
| Interest cost | 3,476,000us-gaap_DefinedBenefitPlanInterestCost | 3,355,000us-gaap_DefinedBenefitPlanInterestCost | 3,625,000us-gaap_DefinedBenefitPlanInterestCost |
| Fair value of plan assets at January 1, | 11,680,000us-gaap_DefinedBenefitPlanFairValueOfPlanAssets | ||
| Fair value of plan assets at December 31, | 10,761,000us-gaap_DefinedBenefitPlanFairValueOfPlanAssets | 11,680,000us-gaap_DefinedBenefitPlanFairValueOfPlanAssets | |
| Ending balance at fair value (net pension plan benefit liability) | 105,417,000us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet | 90,982,000us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet | |
| Defined Benefit Obligations [Member] | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Benefit obligation at January 1, | 102,662,000us-gaap_DefinedBenefitPlanBenefitObligation / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_DefinedBenefitObligationsMember |
101,766,000us-gaap_DefinedBenefitPlanBenefitObligation / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_DefinedBenefitObligationsMember |
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| Service cost | 3,559,000us-gaap_DefinedBenefitPlanServiceCost / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_DefinedBenefitObligationsMember |
4,205,000us-gaap_DefinedBenefitPlanServiceCost / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_DefinedBenefitObligationsMember |
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| Interest cost | 3,476,000us-gaap_DefinedBenefitPlanInterestCost / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_DefinedBenefitObligationsMember |
3,355,000us-gaap_DefinedBenefitPlanInterestCost / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_DefinedBenefitObligationsMember |
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| Actuarial (gain) loss | 25,838,000us-gaap_DefinedBenefitPlanActuarialGainLoss / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_DefinedBenefitObligationsMember |
(6,160,000)us-gaap_DefinedBenefitPlanActuarialGainLoss / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_DefinedBenefitObligationsMember |
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| Benefits paid | (5,519,000)us-gaap_DefinedBenefitPlanBenefitsPaid / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_DefinedBenefitObligationsMember |
(5,369,000)us-gaap_DefinedBenefitPlanBenefitsPaid / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_DefinedBenefitObligationsMember |
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| Foreign currency exchange rate changes | (13,921,000)us-gaap_DefinedBenefitPlanForeignCurrencyExchangeRateChangesBenefitObligation / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_DefinedBenefitObligationsMember |
2,698,000us-gaap_DefinedBenefitPlanForeignCurrencyExchangeRateChangesBenefitObligation / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_DefinedBenefitObligationsMember |
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| Other | 83,000us-gaap_DefinedBenefitPlanOtherCosts / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_DefinedBenefitObligationsMember |
2,167,000us-gaap_DefinedBenefitPlanOtherCosts / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_DefinedBenefitObligationsMember |
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| Benefit obligation at December 31, | 116,178,000us-gaap_DefinedBenefitPlanBenefitObligation / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_DefinedBenefitObligationsMember |
102,662,000us-gaap_DefinedBenefitPlanBenefitObligation / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_DefinedBenefitObligationsMember |
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| Benefits paid | (5,519,000)us-gaap_DefinedBenefitPlanBenefitsPaid / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_DefinedBenefitObligationsMember |
(5,369,000)us-gaap_DefinedBenefitPlanBenefitsPaid / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_DefinedBenefitObligationsMember |
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| Fair Value of Plan Assets [Member] | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Benefits paid | (433,000)us-gaap_DefinedBenefitPlanBenefitsPaid / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_FairValueOfPlanAssetsMember |
(537,000)us-gaap_DefinedBenefitPlanBenefitsPaid / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_FairValueOfPlanAssetsMember |
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| Fair value of plan assets at January 1, | 11,680,000us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_FairValueOfPlanAssetsMember |
8,561,000us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_FairValueOfPlanAssetsMember |
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| Actual return on plan assets | 494,000us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_FairValueOfPlanAssetsMember |
119,000us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_FairValueOfPlanAssetsMember |
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| Company contributions | 375,000us-gaap_DefinedBenefitPlanContributionsByEmployer / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_FairValueOfPlanAssetsMember |
436,000us-gaap_DefinedBenefitPlanContributionsByEmployer / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_FairValueOfPlanAssetsMember |
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| Benefits paid | (433,000)us-gaap_DefinedBenefitPlanBenefitsPaid / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_FairValueOfPlanAssetsMember |
(537,000)us-gaap_DefinedBenefitPlanBenefitsPaid / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_FairValueOfPlanAssetsMember |
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| Foreign currency exchange rate changes | (1,355,000)us-gaap_DefinedBenefitPlanForeignCurrencyExchangeRateChangesPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_FairValueOfPlanAssetsMember |
(267,000)us-gaap_DefinedBenefitPlanForeignCurrencyExchangeRateChangesPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_FairValueOfPlanAssetsMember |
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| Defined Benefit Plan, Other Changes, Plan Assets | 0itri_DefinedBenefitPlanOtherChangesPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_FairValueOfPlanAssetsMember |
3,368,000itri_DefinedBenefitPlanOtherChangesPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_FairValueOfPlanAssetsMember |
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| Fair value of plan assets at December 31, | 10,761,000us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_FairValueOfPlanAssetsMember |
11,680,000us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_FairValueOfPlanAssetsMember |
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| Ending balance at fair value (net pension plan benefit liability) | $ 105,417,000us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_FairValueOfPlanAssetsMember |
$ 90,982,000us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = itri_FairValueOfPlanAssetsMember |
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| X | ||||||||||
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- Definition
Changes in plan assets for reasons other than those separately disclosed. No definition available.
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- Definition
The difference between fair value of plan assets at the end of the period and the fair value at the beginning of the period, adjusted for contributions and payments of benefits during the period, and after adjusting for taxes and other expenses, as applicable. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Amount of gain (loss) related to change in benefit obligation resulting from changes in actuarial assumptions, for example, but not limited to, interest, mortality, employee turnover, salary, and temporary deviation from the substantive plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
The aggregate net amount recognized in the balance sheet associated with the defined benefit plan(s). Will normally be the same as the Defined Benefit Plan, Funded Status of Plan, Total. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
1) For defined benefit pension plans, the benefit obligation is the projected benefit obligation, which is the actuarial present value as of a date of all benefits attributed by the pension benefit formula to employee service rendered prior to that date. 2) For other postretirement defined benefit plans, the benefit obligation is the accumulated postretirement benefit obligation, which is the actuarial present value of benefits attributed to employee service rendered to a particular date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
The amount of payments made for which participants are entitled under a pension plan, including pension benefits, death benefits, and benefits due on termination of employment. Also includes payments made under a postretirement benefit plan, including prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services. This item represents a periodic decrease to the plan obligations and a decrease to plan assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The increase in the fair value of plan assets from contributions made by the employer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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- Definition
Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Amount of gain (loss) from foreign currency exchange rate changes for benefit obligation for plans of a foreign operation whose functional currency is not the reporting currency. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The amount of increase or decrease in plan assets attributed to foreign currency changes. The effects of foreign currency exchange rate changes that are to be disclosed are those applicable to plans of a foreign operation whose functional currency is not the reporting currency. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The increase in a defined benefit pension plan's projected benefit obligation or a defined benefit postretirement plan's accumulated postretirement benefit obligation due to the passage of time. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Amount of other defined benefit plan costs. No definition available.
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- Definition
The actuarial present value of benefits attributed by the pension benefit formula to services rendered by employees during the period. The portion of the expected postretirement benefit obligation attributed to employee service during the period. The service cost component is a portion of the benefit obligation and is unaffected by the funded status of the plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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- Details
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