Stockholder's Investments - Schedule of Other Activity in Stockholders' Investments (Details) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2016
Class of Stock [Line Items]
Sale Of Shares At Cost	$ 0	$ 0	$ (41)
Purchase Of Shares At Cost	0	0	(610)
Ending Balance, Other Stockholders Equity	0	0	0	$ (3,863)
Shares Held Rabbi Trust At Cost [Member]
Class of Stock [Line Items]
Sale Of Shares At Cost	(928)	(977)	(1,288)
Purchase Of Shares At Cost	(1,212)	(1,075)	(925)
Ending Balance, Other Stockholders Equity	$ (8,506)	$ (8,222)	$ (8,124)	$ (8,487)
Ending Balance, Other Stockholders Equity Shares	285,533	299,916	314,082	347,081
Deferred Compensation [Member]
Class of Stock [Line Items]
Sale Of Shares At Cost	$ (928)	$ (977)	$ (1,247)
Purchase Of Shares At Cost	1,212	1,075	315
Ending Balance, Other Stockholders Equity	$ 8,506	$ 8,222	$ 8,124	$ 4,624
Ending Balance, Other Stockholders Equity Shares	285,533	299,916	314,082	201,418