OTHER CURRENT AND NON-CURRENT ASSETS (Details 3) (USD $) In Thousands	Jul. 31, 2011	Jul. 31, 2010
Available for sale securities continuous unrealized loss position less than twelve months fair value	$ 3,487	$ 1,357
Available for sale securities continuous unrealized loss position less than 12 months aggregate losses	63	10
Available for sale securities continuous unrealized loss position twelve months or longer fair value	0	0
Available for sale securities continuous unrealized loss position 12 months or longer aggregate losses	0	0
Available for sale securities continuous unrealized loss position fair value	3,487	1,357
Available for sale securities continuous unrealized loss position aggregate losses	63	10
Other U.S. government [Member]
Available for sale securities continuous unrealized loss position less than twelve months fair value		723
Available for sale securities continuous unrealized loss position less than 12 months aggregate losses		5
Available for sale securities continuous unrealized loss position twelve months or longer fair value		0
Available for sale securities continuous unrealized loss position 12 months or longer aggregate losses		0
Available for sale securities continuous unrealized loss position fair value		723
Available for sale securities continuous unrealized loss position aggregate losses		5
Corporate Debt Securities [Member]
Available for sale securities continuous unrealized loss position less than twelve months fair value	3,487	634
Available for sale securities continuous unrealized loss position less than 12 months aggregate losses	63	5
Available for sale securities continuous unrealized loss position twelve months or longer fair value	0	0
Available for sale securities continuous unrealized loss position 12 months or longer aggregate losses	0	0
Available for sale securities continuous unrealized loss position fair value	3,487	634
Available for sale securities continuous unrealized loss position aggregate losses	$ 63	$ 5