Segment Reporting (Details) (USD $)	3 Months Ended				6 Months Ended
	Jan. 31, 2015		Jan. 31, 2014		Jan. 31, 2015		Jan. 31, 2014		Jul. 31, 2014
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 17,566,091		$ 18,512,418		$ 39,418,613		$ 41,607,364
Long-Lived Assets	27,089,787				27,089,787				31,170,634
Foreign Countries [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	10,595,570	[1]	10,564,854	[1]	21,933,699	[1]	22,219,199	[1]
Long-Lived Assets	5,108,630				5,108,630				5,386,736
Peru [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	5,700,000		4,100,000		12,300,000		8,500,000
Brazil [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	2,500,000		2,600,000		5,200,000		6,600,000
Chile [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 1,700,000		$ 2,400,000		$ 3,200,000		$ 4,800,000

[1] Significant foreign revenues included revenues in Peru ($5.7 million and $4.1 million for the three months ended January 31, 2015 and 2014, respectively, and $12.3 million and $8.5 million for the six months ended January 31, 2015 and 2014, respectively), Brazil ($2.5 million and $2.6 million for the three months ended January 31, 2015 and 2014, respectively, and $5.2 million and $6.6 million for the six months ended January 31, 2015 and 2014, respectively) and Chile ($1.7 million and $2.4 million for the three months ended January 31, 2015 and 2014, respectively, and $3.2 million and $4.8 million for the six months ended January 31, 2015 and 2014, respectively).