Contract Receivables, net, Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2016
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at beginning of period	$ 2,044	$ 6,792	$ 6,817
Provision for doubtful accounts during the period	813	682	1,164
Write-offs and recoveries of allowance recorded in prior periods	(943)	(5,430)	(1,189)
Reclassification of allowance from current to noncurrent	(630)	0	0
Balance at end of period	$ 1,284	2,044	$ 6,792
Reversal of allowance for doubtful accounts		4,900
Specific write offs of aged and uncollectable contract receivables		$ 4,900