Document and Entity Information Document - USD ($)	12 Months Ended
	Dec. 31, 2015	May 31, 2016	Jun. 30, 2015
Entity Information [Line Items]
Entity Registrant Name	ITRON INC /WA/
Entity Central Index Key	0000780571
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	FY
Amendment Flag	false
Trading Symbol	ITRI
Entity Common Stock, Shares Outstanding		38,243,435
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	No
Entity Public Float			$ 1,309,640,099