Defined Contribution Bonus and Profit Sharing Plans Schedule of Bonus and Profit Sharing Plans Expense (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Bonus and Profit Sharing Plans and Awards Expense	$ 14,192	$ 34,989	$ 18,602

Expense recognized in the period related to bonus and profit sharing plans and other awards for employee achievement.

No definition available.

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