Commitments and Contingencies Warranty Expense (Details) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Warranty charge	$ 4,000,000itri_WarrantyCharge
Warranty Expense	10,170,000itri_WarrantyExpense	15,904,000itri_WarrantyExpense	13,186,000itri_WarrantyExpense
Product Warranty Expense, Change	$ 5,700,000itri_ProductWarrantyExpenseChange	$ 2,700,000itri_ProductWarrantyExpenseChange

This tag represents specific cases of warranty charges (adjustments) disclosed. This is a subset of the tag itri_WarrantyChangesAndAdjustments, which is defined as "Represents the aggregate Increase or Decrease in the liability during the reporting period for accruals related to preexisting product warranties (including adjustments for changes in estimates)."

No definition available.

Name:	itri_WarrantyCharge
Namespace Prefix:	itri_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration