Annual report pursuant to Section 13 and 15(d)

Summary of significant accounting policies (Details) - Allowance for doubtful accounts

v3.3.0.814
Summary of significant accounting policies (Details) - Allowance for doubtful accounts - USD ($)
$ in Thousands
12 Months Ended
Jul. 31, 2015
Jul. 31, 2014
Jul. 31, 2013
Allowance for doubtful accounts [Abstract]      
Beginning balance $ 2,142 $ 2,707  
Provision for doubtful accounts 2,284 3,063 $ 4,496
Write-offs (2,640) (3,628)  
Ending balance $ 1,786 $ 2,142 $ 2,707