Restructuring Accrual Activity (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended											12 Months Ended
	Jul. 31, 2014	Apr. 30, 2014	Jan. 31, 2014	Jul. 31, 2013	Apr. 30, 2013	Jan. 31, 2013	Oct. 31, 2012	Jul. 31, 2012	Apr. 30, 2012	Jan. 31, 2012	Oct. 31, 2011	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Restructuring Cost and Reserve [Line Items]
Beginning Balance							$ 4,060				$ 4,767	$ 2,774	$ 4,060	$ 4,767
Balance assumed from Dover acquisition												447
Restructuring expense	363	1,422	2,159	(180)	356	69	231	178	739	141	46	3,944	476	1,103
Accretion												274	229	182
Stock based compensation													(47)	(84)
Cash paid												(4,887)	(1,944)	(1,908)
Ending Balance	2,552			2,774				4,060				2,552	2,774	4,060
Employee Severance
Restructuring Cost and Reserve [Line Items]
Beginning Balance							363				6	2	363	6
Balance assumed from Dover acquisition												447
Restructuring expense												3,534	216	812
Stock based compensation													(47)	(84)
Cash paid												(3,562)	(530)	(371)
Ending Balance	421			2				363				421	2	363
Facility Lease
Restructuring Cost and Reserve [Line Items]
Beginning Balance							3,697				4,761	2,772	3,697	4,761
Restructuring expense												410	260	291
Accretion												274	229	182
Cash paid												(1,325)	(1,414)	(1,537)
Ending Balance	$ 2,131			$ 2,772				$ 3,697				$ 2,131	$ 2,772	$ 3,697