Document and Entity Information	6 Months Ended
	Jan. 31, 2013	Mar. 01, 2013 Class A [Member]	Mar. 01, 2013 Class B [Member]
Document and Entity Information [Abstract]
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	Yes
Entity Filer Category	Smaller Reporting Company
Statement [Line Items]
Entity Common Stock, Shares Outstanding		2,607,427	1,643,773
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q2
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jan. 31, 2013