Contract Receivables, net (Details) (USD $)	3 Months Ended
	Oct. 31, 2012	Oct. 29, 2011	Jul. 31, 2012
Contracts Receivable [Line Items]
Billed Contracts Receivable	$ 40,781,996		$ 42,977,016
Unbilled Contracts Receivable	31,193,272		28,829,818
Contracts Recevable, Gross	71,975,268		71,806,834
Allowance for doubtful accounts and contract adjustments	(11,322,000)		(10,238,391)
Contract Receivable, net	60,653,268		61,568,443
Contract receivable retainage	246,000		248,000
Provision for allowance for doubtful accounts and contract adjustments	1,100,000	200,000
Contracts receivable from Kuwait	14,500,000		14,500,000
Billings in excess of revenue	1,700,000		1,900,000
China [Member]
Contracts Receivable [Line Items]
Billed Contracts Receivable	$ 4,700,000		$ 2,800,000