Stockholder's Investments - Schedule of Other Activity in Stockholders' Investments (Details) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014	Jul. 31, 2013
Class of Stock [Line Items]
Sale Of Shares At Cost	$ 40	$ (90)	$ (141)
Purchase Of Shares At Cost	(839)	(815)	0
Forfeitures of Restricted Stock			(2,435)
Amortization Of Restricted Stock			1,137
Ending Balance, Other Stockholders Equity	(3,863)	(3,064)	(2,159)	$ (720)
Unearned Restricted Stock [Member]
Class of Stock [Line Items]
Sale Of Shares At Cost	0	0	0
Purchase Of Shares At Cost	0	0	0
Forfeitures of Restricted Stock			0
Amortization Of Restricted Stock			1,137
Ending Balance, Other Stockholders Equity	0	0	0	(1,137)
Shares Held Rabbi Trust At Cost [Member]
Class of Stock [Line Items]
Sale Of Shares At Cost	1,278	2,235	1,496
Purchase Of Shares At Cost	(1,017)	(1,035)	(821)
Forfeitures of Restricted Stock			0
Amortization Of Restricted Stock			0
Ending Balance, Other Stockholders Equity	$ (8,487)	$ (8,748)	$ (9,948)	$ (10,623)
Ending Balance, Other Stockholders Equity Shares	347,081	362	423	470
Deferred Compensation [Member]
Class of Stock [Line Items]
Sale Of Shares At Cost	$ (1,238)	$ (2,325)	$ (1,637)
Purchase Of Shares At Cost	178	220	821
Forfeitures of Restricted Stock			(2,435)
Amortization Of Restricted Stock			0
Ending Balance, Other Stockholders Equity	$ 4,624	$ 5,684	$ 7,789	$ 11,040
Ending Balance, Other Stockholders Equity Shares	201,418	252	339	470