Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014
Earnings Per Share [Abstract]
Net (loss) income attributable to Ecology and Environment, Inc.	$ 886	$ 3,396	$ (1,383)
Dividend declared	1,895	2,066	2,066
Undistributed earnings	$ (1,009)	$ 1,330	$ (3,449)
Weighted-average common shares outstanding (basic and diluted) (in shares)	4,289,993	4,287,775	4,283,984
Distributed earnings per share (in dollars per share)	$ 0.44	$ 0.48	$ 0.48
Undistributed earnings per share (in dollars per share)	(0.23)	0.31	(0.80)
Total earnings per share (in dollars per share)	$ 0.21	$ 0.79	$ (0.32)