Accounts Receivable Accounts Receivable (Details) - USD ($) $ in Thousands	3 Months Ended
	Oct. 31, 2020	Jul. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Revenue, Practical Expedient, Financing Component [true false]	true
Accounts Receivable, before Allowance for Credit Loss, Current	$ 414,409	$ 356,597
Less: Allowance for credit loss	6,512	6,390
Accounts receivable, net	407,897	350,207
Advance charges receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, before Allowance for Credit Loss, Current	314,371	260,196
Trade accounts receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, before Allowance for Credit Loss, Current	97,583	94,281
Other receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, before Allowance for Credit Loss, Current	$ 2,455	$ 2,120