Commitments and Contingencies (Details)	3 Months Ended
	Oct. 31, 2013 City of Denver [Member] USD ($)	Oct. 31, 2013 Walsh Environmental Scientists and Engineers [Member] USD ($)	Oct. 31, 2013 Pending Litigation [Member] Ecology and Environment do Brasil LTDA [Member] USD ($) Employee	Oct. 31, 2013 Pending Litigation [Member] Ecology and Environment do Brasil LTDA [Member] BRL Employee
Loss Contingencies [Line Items]
Penalty	$ 200,000	$ 100,000
Supplemental Environmental Project		100,000
Loss Contingency, Estimate of Possible Loss			$ 200,000	520,000
Number of employees individually served with Notices of Infraction			4	4