Accumulated Other Comprehensive Income (Loss) (Details) (USD $)	12 Months Ended
	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2011
Components and changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period	$ 8,175,000	$ 9,283,000	$ 8,045,000
Other comprehensive gain (loss)		(1,493,000)	1,558,000
Income tax effect on other comprehensive gain (loss)		385,000	(320,000)
Other comprehensive loss before reclassifications	(485,000)
Income tax effect on other comprehensive loss before reclassifications	3,148,000
Reclassification adjustments to interest expense for losses on interest rate swaps included in net income during the period	222,000
Income tax effect on reclassification adjustments	(83,000)
Balance at the end of the period	10,977,000	8,175,000	9,283,000
Foreign Currency Translation Adjustments
Components and changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period	8,385,000	9,283,000	8,045,000
Other comprehensive gain (loss)		(1,158,000)	1,558,000
Income tax effect on other comprehensive gain (loss)		260,000	(320,000)
Other comprehensive loss before reclassifications	(435,000)
Income tax effect on other comprehensive loss before reclassifications	3,130,000
Balance at the end of the period	11,080,000	8,385,000	9,283,000
Interest Rate Swap Agreements
Components and changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period	(210,000)
Other comprehensive gain (loss)		(335,000)
Income tax effect on other comprehensive gain (loss)		125,000
Other comprehensive loss before reclassifications	(50,000)
Income tax effect on other comprehensive loss before reclassifications	18,000
Reclassification adjustments to interest expense for losses on interest rate swaps included in net income during the period	222,000
Income tax effect on reclassification adjustments	(83,000)
Balance at the end of the period	$ (103,000)	$ (210,000)