Lines of Credit (Details) (USD $)	6 Months Ended		12 Months Ended
	Jan. 31, 2013	Oct. 29, 2011	Jul. 31, 2012
Line of Credit Facility [Line Items]
Cash draws, recorded as lines of credit on the consolidated balance sheet	$ 6,758,538		$ 12,309,335
Letters of credit	1,577,931		2,615,415
Total amounts drawn under lines of credit	8,336,469		14,924,750
Remaining amounts available under lines of credit	26,032,531		19,444,250
Total approved unsecured lines of credit	$ 34,369,000		$ 34,369,000
Interest rate, minimum (in hundredths)	2.50%	5.00%	2.50%
Interest rate, maximum (in hundredths)	3.00%	14.00%	5.00%