Stockholder's Investments - Schedule of Other Activity in Stockholders' Investments (Details) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2017
Class of Stock [Line Items]
Sale Of Shares At Cost	$ 0	$ 0	$ 0
Purchase Of Shares At Cost	0	0	0
Ending Balance, Other Stockholders Equity	0	0	0	$ 0
Shares Held Rabbi Trust At Cost [Member]
Class of Stock [Line Items]
Sale Of Shares At Cost	(460)	(928)	(977)
Purchase Of Shares At Cost	(1,293)	(1,212)	(1,075)
Ending Balance, Other Stockholders Equity	$ (9,339)	$ (8,506)	$ (8,222)	$ (8,124)
Ending Balance, Other Stockholders Equity Shares	292,329	285,533	299,916	314,082
Deferred Compensation [Member]
Class of Stock [Line Items]
Sale Of Shares At Cost	$ (460)	$ (928)	$ (977)
Purchase Of Shares At Cost	(1,293)	(1,212)	(1,075)
Ending Balance, Other Stockholders Equity	$ 9,339	$ 8,506	$ 8,222	$ 8,124
Ending Balance, Other Stockholders Equity Shares	292,329	285,533	299,916	314,082