Description of Business and Summary of Significant Accounting Policies (Details 3) - USD ($) $ in Thousands		12 Months Ended
		Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014
Reserves deducted from accounts receivable:
Allowance for doubtful accounts, Balance at beginning of year		$ 5,645	$ 11,507	$ 13,079
Allowance for doubtful accounts, Additions charged to costs and expenses		1,519	97	500
Allowance for doubtful accounts, Deductions	[1]	(2,346)	(5,959)	(2,072)
Allowance for doubtful accounts, Balance at end of year		$ 4,818	$ 5,645	$ 11,507

[1] Primarily uncollectible accounts written off, net of recoveries.