Accounts Receivable Accounts Receivable (Details) - USD ($) $ in Thousands	6 Months Ended
	Jan. 31, 2020	Jul. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Revenue, Practical Expedient, Financing Component [true false]	false
Accounts Receivable, before Allowance for Credit Loss, Current	$ 452,279	$ 372,207
Less: Allowance for doubtful accounts	6,316	4,942
Accounts receivable, net	445,963	367,265
Advance charges receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, before Allowance for Credit Loss, Current	349,517	280,835
Trade accounts receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, before Allowance for Credit Loss, Current	98,529	89,274
Other receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, before Allowance for Credit Loss, Current	$ 4,233	$ 2,098