Summary of Significant Accounting Policies - Restructuring (Details)	12 Months Ended
Dec. 31, 2018
Accounting Policies [Abstract]
Remaining service period of terminated employees	60 days

Restructuring Costs, Employee Termination, Required Service Period

No definition available.

Name:	itri_RestructuringCostsEmployeeTerminationRequiredServicePeriod
Namespace Prefix:	itri_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration