Warranty (Details) (USD $)
In Thousands, unless otherwise specified
6 Months Ended
Jan. 31, 2015
Jan. 31, 2014
Warranty [Abstract]    
Beginning balance $ 9,029 $ 10,526
Accruals for warranties issued during the reporting period 1,617 1,710
Accruals related to pre-existing warranties (including changes in estimates) (204) (342)
Less settlements made during the period (2,020) (2,404)
Ending balance $ 8,422 $ 9,490