v3.5.0.2
Document and Entity Information - shares
9 Months Ended
Jun. 30, 2016
Jul. 15, 2016
Document And Entity Information [Abstract]    
Entity Registrant Name FAIR ISAAC CORP  
Trading Symbol FICO  
Entity Central Index Key 0000814547  
Current Fiscal Year End Date --09-30  
Entity Filer Category Large Accelerated Filer  
Document Type 10-Q  
Document Period End Date Jun. 30, 2016  
Document Fiscal Year Focus 2016  
Document Fiscal Period Focus Q3  
Amendment Flag false  
Entity Common Stock, Shares Outstanding   30,854,567