Warranty (Details) (USD $)	3 Months Ended
	Oct. 31, 2014	Oct. 31, 2013
Warranty [Abstract]
Beginning balance	$ 9,029,000	$ 10,526,000
Accruals for warranties issued during the reporting period	859,000	1,096,000
Accruals related to pre-existing warranties (including changes in estimates)	(542,000)	230,000
Less settlements made during the period	(1,290,000)	(1,640,000)
Ending balance	8,056,000	10,212,000
Specific warranty matters accrued	$ 0	$ 0