Warranty (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jul. 31, 2014	Jul. 31, 2013
Warranty [Abstract]
Beginning balance	$ 10,526	$ 10,905
Accruals for warranties issued during the reporting period	4,339	5,940
Accruals related to pre-existing warranties (including changes in estimates)	(1,185)	(1,081)
Less settlements made during the period	(4,651)	(5,238)
Ending balance	$ 9,029	$ 10,526