Segment Reporting (Details) (USD $)	3 Months Ended				6 Months Ended
	Jan. 31, 2014		Jan. 31, 2013		Jan. 31, 2014		Jan. 31, 2013		Jul. 31, 2013
United States [Member]
Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Line Items]
Revenue	$ 18,512,418		$ 21,888,483		$ 41,607,364		$ 45,978,251
Gross Long-Lived Assets	30,165,443				30,165,443				29,508,055
Foreign Countries [Member]
Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Line Items]
Revenue	10,564,854	[1]	14,263,000	[1]	22,219,199	[1]	26,995,000	[1]
Gross Long-Lived Assets	5,142,756				5,142,756				5,183,885
Peru [Member]
Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Line Items]
Revenue	4,100,000		2,200,000		8,500,000		5,800,000
Brazil [Member]
Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Line Items]
Revenue	2,600,000		3,700,000		6,600,000		7,800,000
Chile [Member]
Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Line Items]
Revenue	$ 2,400,000		$ 3,200,000		$ 4,800,000		$ 5,800,000

[1] (1)     Significant foreign revenues included revenues in Peru ($4.1 million and $2.2 million for the three months ended January 31, 2014 and 2013, respectively, and $8.5 million and $5.8 million for the six months ended January 31, 2014 and 2013, respectively), Brazil ($2.6 million and $3.7 million for the three months ended January 31, 2014 and 2013, respectively, and $6.6 million and $7.8 million for the six months ended January 31, 2014 and 2013, respectively) and Chile ($2.4 million and $3.2 million for the three months ended January 31, 2014 and 2013, respectively, and $4.8 million and $5.8 million for the six months ended January 31, 2014 and 2013, respectively).