XML 42 R28.htm IDEA: XBRL DOCUMENT v3.5.0.2
Activity in Allowance for Doubtful Accounts (Detail) - USD ($)
$ in Thousands
 12 Months Ended
May 31, 2016
May 31, 2015
May 31, 2014
Financing Receivable, Allowance for Credit Losses [Line Items]      
Beginning Balance $ 1,300 $ 1,200 $ 900
Provision 305 337 367
Recoveries 90 92 8
Write-offs (195) (329) (75)
Ending Balance $ 1,500 $ 1,300 $ 1,200