Document and Entity Information - USD ($)
$ in Millions
12 Months Ended
Jul. 31, 2018
Aug. 31, 2018
Jan. 31, 2018
Document and Entity Information [Abstract]      
Entity Registrant Name Guidewire Software, Inc.    
Entity Central Index Key 0001528396    
Current Fiscal Year End Date --07-31    
Entity Filer Category Large Accelerated Filer    
Document Type 10-K    
Document Period End Date Jul. 31, 2018    
Document Fiscal Year Focus 2018    
Document Fiscal Period Focus FY    
Amendment Flag false    
Entity Common Stock, Shares Outstanding (in shares)   80,608,319  
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Public Float     $ 3,400