Accounts Receivable, Net (Details) - USD ($) $ in Thousands	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, gross, current	$ 357,045	$ 316,157
Less allowance for doubtful accounts	(5,444)	(4,311)	$ (4,120)	$ (2,988)
Accounts receivable, net	351,601	311,846
Advance charges receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, gross, current	230,092	204,097
Trade accounts receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, gross, current	125,255	110,189
Other receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, gross, current	$ 1,698	$ 1,871