Warranties (Details) (USD $)	3 Months Ended		9 Months Ended
	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2013	Apr. 30, 2012
Summary of activity in warranty reserves
Beginning balance	$ 1,232,000	$ 2,081,000	$ 1,667,000	$ 2,083,000
Provisions	479,000	748,000	1,182,000	2,528,000
Settlements	(634,000)	(881,000)	(1,772,000)	(2,661,000)
Foreign currency translation		1,000		(1,000)
Ending Balance	$ 1,077,000	$ 1,949,000	$ 1,077,000	$ 1,949,000