Commitments and Contingencies (Details) $ in Thousands	12 Months Ended
	Jul. 31, 2017 USD ($) Employee	Jul. 31, 2017 BRL	Jul. 31, 2016 USD ($)
Loss Contingencies [Line Items]
Other accrued liabilities | $	$ 2,645		$ 3,445
Pending Litigation [Member] | Ecology and Environment do Brasil LTDA [Member]
Loss Contingencies [Line Items]
Loss contingency, estimate of possible loss | BRL		BRL 520,000
Number of employees individually served with notices of infraction	4
Settled Litigation [Member] | Ecology and Environment do Brasil LTDA [Member]
Loss Contingencies [Line Items]
Number of employees individually served with claim of violations dismissed	1
Number of employees that have fines assessed against them, which are being appealed	3
Other accrued liabilities | $	$ 400