v2.3.0.15
Entity Information (USD $)
9 Months Ended
Sep. 30, 2011
Oct. 31, 2011
Jun. 30, 2010
Entity Registrant NameOn Assignment Inc  
Entity Central Index Key0000890564  
Current Fiscal Year End Date--12-31  
Entity Well-known Seasoned IssuerNo  
Entity Voluntary FilersNo  
Entity Current Reporting StatusYes  
Entity Filer CategoryAccelerated Filer  
Entity Common Stock, Shares Outstanding 36,865,528 
Document Fiscal Year Focus2011  
Document Fiscal Period FocusQ3  
Entity Public Float  $ 134,513,487