Employee Benefit Plans (Details Textual) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jul. 31, 2012 Claims Age	Jul. 31, 2011	Jul. 31, 2010
Employee Benefit Plans (Textual) [Abstract]
Retirement age on credited service	55
Period of credited service	15 years
Minimum age for accrual credit service	40
Elimination of dental benefits	$ (1,105)
Estimated actuarial gain to be amortized from accumulated other comprehensive income into net periodic postretirement benefit cost over the next fiscal year	45
Estimated prior service credit to be amortized from accumulated other comprehensive income into net periodic postretirement benefit cost over the next fiscal year	203
Accrued profit-sharing included in other current liabilities and other long-term liabilities	4,371	4,752
Deferred compensation included in current and other long-term liabilities	13,738	12,299
Expense for retirement and profit sharing	14,458	14,911	12,547
Age of excluding dental and vision benefits for retirees	65
Benefit payments for retirees	2,062	671
Large claims realized within the self-insured retiree population	4
Discount rate utilized in preparing the accumulated postretirement benefit obligation liability	3.25%	4.50%	4.50%
Pre-tax amounts recognized in accumulated other comprehensive income	(828)	525
Accumulated pension obligation related to benefit pension plans	4,021	2,612
Net periodic benefit cost for benefit pension plans	$ 885	$ 1,202	$ 1,187