Segment Reporting (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jan. 26, 2019	Jan. 27, 2018	Jan. 26, 2019	Jan. 27, 2018	Jul. 31, 2018
Segment Reporting Information [Abstract]
Gross revenue		$ 20,252	$ 21,289	$ 42,004	$ 47,394
Net income (loss) attributable to EEI		(309)	(519)	(429)	69
Depreciation and amortization expense		264	259	541	519
Total assets		51,529		51,529		$ 52,829
U.S. Operations [Member]
Segment Reporting Information [Abstract]
Gross revenue		16,303	16,384	34,313	37,219
Net income (loss) attributable to EEI	[1]	(294)	(480)	(402)	(176)
Depreciation and amortization expense		200	200	400	400
Total assets		43,991		43,991		43,823
U.S. Operations [Member] | Government Contracts [Member]
Segment Reporting Information [Abstract]
Gross revenue		2,900	4,400	6,000	8,000
South American Operations [Member]
Segment Reporting Information [Abstract]
Gross revenue		3,949	4,905	7,691	10,175
Net income (loss) attributable to EEI	[2]	(15)	(39)	(27)	245
Depreciation and amortization expense		100	$ 100	200	$ 100
Total assets		$ 7,538		$ 7,538		$ 9,006

[1] Includes depreciation and amortization expense of $0.2 million for the three months ended January 26, 2019 and January 27, 2018, and $0.4 million for the six months ended January 26, 2019 and January 27, 2018.

[2] Includes depreciation and amortization expense of $0.1 million three months ended January 26, 2019 and January 27, 2018, and $0.2 million and $0.1million for the six months ended January 26, 2019 and January 27, 2018, respectively.