Document and Entity Information In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Oct. 18, 2012
Document and Entity Information Abstract
Entity Registrant Name	INTERNAP NETWORK SERVICES CORP
Entity Central Index Key	0001056386
Trading Symbol	inap
Entity Current Reporting Status	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock Shares Outstanding		53,455,807
Document Type	10-Q
Document Period End Date	Sep. 30, 2012
Amendment Flag	false
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q3