Restructuring (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Jul. 31, 2012	Apr. 30, 2012	Jan. 31, 2012	Oct. 31, 2011	Jul. 31, 2011	Apr. 30, 2011	Jan. 31, 2011	Oct. 31, 2010	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2010
Restructuring reserve roll forward
Beginning balance				$ 2,256				$ 6,161	$ 2,256	$ 6,161	$ 5,322
Restructuring charges	8,670	3,440			2,202	1,211	2,134	3,641	12,110	9,188	15,314
Non-cash write-offs									(458)	(2,155)	(2,260)
Cash payments									(4,834)	(10,938)	(12,215)
Ending balance	9,074				2,256				9,074	2,256	6,161
Employee Related [Member]
Restructuring reserve roll forward
Beginning balance				2,207				6,055	2,207	6,055	4,445
Restructuring charges									10,944	6,341	10,850
Cash payments									(4,342)	(10,189)	(9,240)
Ending balance	8,809				2,207				8,809	2,207	6,055
Asset Write-offs [Member]
Restructuring reserve roll forward
Restructuring charges									458	2,155	2,260
Non-cash write-offs									(458)	(2,155)	(2,260)
Other [Member]
Restructuring reserve roll forward
Beginning balance				49				106	49	106	877
Restructuring charges									708	692	2,204
Cash payments									(492)	(749)	(2,975)
Ending balance	$ 265				$ 49				$ 265	$ 49	$ 106