Stockholder's Investments - Schedule of Other Activity in Stockholders' Investments (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2010
Class of Stock [Line Items]
Other Stockholders Equity	$ (720)	$ (3,304)	$ (4,864)	$ (2,829)
Sale Of Shares At Cost	(42)	(39)	(46)
Purchase Of Shares At Cost	0	0	0
Stock Issued During Period, Value, Restricted Stock Award, Forfeitures	838
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures			(2,835)
Amortization Of Restricted Stock	1,788	1,599	846
Unearned Restricted Stock [Member]
Class of Stock [Line Items]
Other Stockholders Equity	(1,137)	(3,763)	(5,362)	(3,373)
Sale Of Shares At Cost	0	0	0
Purchase Of Shares At Cost	0	0	0
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures			(2,835)
Amortization Of Restricted Stock	1,788	1,599	846
Shares Held Rabbi Trust At Cost [Member]
Class of Stock [Line Items]
Other Stockholders Equity	(10,623)	(11,151)	(11,595)	(12,304)
Ending Balance Other Stockholders Equity Shares	469,797	517,105	560,078	614,988
Sale Of Shares At Cost	1,419	1,368	1,375
Purchase Of Shares At Cost	(891)	(924)	(666)
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures			0
Amortization Of Restricted Stock	0	0	0
Deferred Compensation [Member]
Class of Stock [Line Items]
Other Stockholders Equity	11,040	11,610	12,093	12,848
Ending Balance Other Stockholders Equity Shares	469,797	517,105	560,078	614,988
Sale Of Shares At Cost	(1,461)	(1,407)	(1,421)
Purchase Of Shares At Cost	891	924	666
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures			0
Amortization Of Restricted Stock	$ 0	$ 0	$ 0