Accounts Receivable, Net (Details) (USD $) In Thousands	12 Months Ended
	Jul. 31, 2011	Jul. 31, 2010	Jul. 31, 2009
Accounts Receivable, Net, Current [Abstract]
Accounts Receivable, Gross, Current	$ 125,981	$ 111,902
Less allowance for doubtful accounts	(3,122)	(2,841)	(2,405)
Accounts receivable, net	122,859	109,061
The Movements In Allowance For Doubtful [Roll Forward]
Balance at Beginning of Year	2,841	2,405	2,600
Charged to Costs And Expenses	478	1,591	783
Deductions to Bad Debt	(197)	(1,155)	(978)
Balance at End of Year	3,122	2,841	2,405
Advance Charges Receivable
Accounts Receivable, Net, Current [Abstract]
Accounts Receivable, Gross, Current	71,961	72,841
Trade Accounts Receivable
Accounts Receivable, Net, Current [Abstract]
Accounts Receivable, Gross, Current	53,569	37,904
Other Receivables
Accounts Receivable, Net, Current [Abstract]
Accounts Receivable, Gross, Current	$ 451	$ 1,157