Segment Reporting (Details) - USD ($) $ in Thousands		3 Months Ended
		Oct. 27, 2018	Oct. 28, 2017	Jul. 31, 2018
Segment Reporting Information [Abstract]
Gross revenue		$ 21,752	$ 26,105
Net income (loss) attributable to EEI		(120)	588
Depreciation and amortization expense		277	260
Total assets		53,411		$ 52,829
U.S. Operations [Member]
Segment Reporting Information [Abstract]
Gross revenue		18,011	20,835
Net income (loss) attributable to EEI	[1]	(107)	306
Depreciation and amortization expense		200	200
Total assets		44,485		43,823
U.S. Operations [Member] | Government Contracts [Member]
Segment Reporting Information [Abstract]
Gross revenue		3,100	4,000
South American Operations [Member]
Segment Reporting Information [Abstract]
Gross revenue		3,741	5,270
Net income (loss) attributable to EEI	[2]	(13)	282
Depreciation and amortization expense		100	$ 100
Total assets		$ 8,926		$ 9,006

[1] Includes depreciation and amortization expense of $0.2 million for the three months ended October 27, 2018 and October 28, 2017.

[2] Includes depreciation and amortization expense of $0.1 million for the three months ended October 27, 2018 and October 28, 2017.