Fair Value Measurements (Details 2) (Recurring basis, USD $)	Oct. 31, 2013	Jul. 31, 2013
Level 1
Assets:
Money markets	$ 4,571,000	$ 4,241,000
Total assets	4,571,000	4,241,000
Level 2
Accrued expenses:
Interest rate swap agreements	112,000	133,000
Total accrued expenses	112,000	133,000
Other long-term liabilities:
Interest rate swap agreements	35,000	29,000
Total other long-term liabilities		29,000
Total liabilities	147,000	162,000
Level 3
Accrued expenses:
Price floor	1,000
Total accrued expenses	1,000
Other long-term liabilities:
Price floor		45,000
Total other long-term liabilities		45,000
Total liabilities	1,000	45,000
Total
Assets:
Money markets	4,571,000	4,241,000
Total assets	4,571,000	4,241,000
Accrued expenses:
Interest rate swap agreements	112,000	133,000
Price floor	1,000
Total accrued expenses	113,000	133,000
Other long-term liabilities:
Price floor		45,000
Interest rate swap agreements	35,000	29,000
Total other long-term liabilities		74,000
Total liabilities	$ 148,000	$ 207,000