Employee Benefit Plans - Additional Information (Detail) (USD $)	12 Months Ended
	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Intrinsic value of options exercised	$ 207,708	$ 1,307	$ 26,160
Profit Sharing Plan
Defined Benefit Plan Disclosure [Line Items]
Profit sharing expenses	300,000	100,000	100,000
Executive Profit Sharing Plan
Defined Benefit Plan Disclosure [Line Items]
Profit sharing expenses	3,200,000	0	0
401(k) Growth and Investment Program
Defined Benefit Plan Disclosure [Line Items]
Percentage employees contribution to 401(k) plan of their annual compensation	20.00%
Percentage of contribution by the company	50.00%
Percentage of contribution by employee	6.00%
Percentage of employer contribution vested per year	20.00%
Percentage of employee contribution vested	100.00%
Employee contribution vesting period	5 years
Defined contribution match funded by company	1,200,000	1,100,000	1,100,000
Bonus Plan
Defined Benefit Plan Disclosure [Line Items]
Profit sharing expenses	1,300,000
Restricted stock units (RSU's)
Defined Benefit Plan Disclosure [Line Items]
Fair value of RSUs vested	4,700,000	4,100,000	4,000,000
Stock Option Plan 2010
Defined Benefit Plan Disclosure [Line Items]
Number of share that can be issued to employees under the plan	4,675,582
2004 ESPP
Defined Benefit Plan Disclosure [Line Items]
Percentage of price paid for common stock	85.00%
Common stock offering period	6 months
Additional number of shares issuable to employees	400,000
Number of shares issued under employee stock purchase plan	114,346	165,572	146,897
Remaining shares to be issued under employee stock purchase plan	598,540
2004 ESPP | October 2012
Defined Benefit Plan Disclosure [Line Items]
Additional number of shares issuable to employees	800,000
2004 ESPP | Maximum
Defined Benefit Plan Disclosure [Line Items]
Employee contribution of annual compensation for purchase of common stock	15.00%
Annual limit for purchase of common stock	$ 25,000
Number of share that can be issued to employees under the plan	400,000