Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2017	Oct. 31, 2019
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ (7,517)
Accounts payable and accrued liabilities (Note 7)	607,857	$ 504,533
Retained earnings	759,801	726,722
Impairment to goodwill or intangible assets	0
Advertising expense	44,600	39,800	$ 40,000
Prior Period Reclassification Adjustment			(6,200)
Increase (Decrease) in Restricted Cash for Operating Activities		3,100	2,200
Restricted cash	9,539	$ 6,895	$ 10,300
Accounts Payable and Accrued Liabilities [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	6,350
Retained Earnings [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	(7,517)
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Net Income	$ (6,350)
Scenario, Forecast [Member]
Right-of-use asset adjustments				$ 33,000
Scenario, Forecast [Member] | Minimum [Member]
Operating Lease, Right-of-Use Asset				212,000
Operating Lease, Liability				245,000
Scenario, Forecast [Member] | Maximum [Member]
Operating Lease, Right-of-Use Asset				232,000
Operating Lease, Liability				$ 265,000