Document and Entity Information
9 Months Ended
Apr. 30, 2013
Jun. 01, 2013
Class A [Member]
Jun. 01, 2013
Class B [Member]
Class of Stock [Line Items]      
Entity Registrant Name ECOLOGY & ENVIRONMENT INC    
Entity Central Index Key 0000809933    
Current Fiscal Year End Date --07-31    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status No    
Entity Filer Category Smaller Reporting Company    
Entity Common Stock, Shares Outstanding   2,606,041 1,643,773
Document Fiscal Year Focus 2013    
Document Fiscal Period Focus Q3    
Document Type 10-Q    
Amendment Flag false    
Document Period End Date Apr. 30, 2013