Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $)	Jan. 31, 2014	Jul. 31, 2013
Assets
Contract receivables, allowance for doubtful accounts and contract adjustments	$ 5,336,972	$ 5,592,800
Property, building and equipment, accumulated depreciation	$ 26,470,095	$ 24,569,139
Shareholders' equity:
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	2,000,000	2,000,000
Preferred stock, issued (in shares)	0	0
Class A [Member]
Shareholders' equity:
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	6,000,000	6,000,000
Common stock, issued (in shares)	2,685,151	2,685,151
Treasury stock (in shares)	39,224	79,110
Class B [Member]
Shareholders' equity:
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	10,000,000	10,000,000
Common stock, issued (in shares)	1,708,574	1,708,574
Treasury stock (in shares)	64,801	64,801