Stock Compensation Plan (Schedule of Share Based Compensation SARs Activity) (Details) - $ / shares shares in Thousands	12 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	1,324	2,290	2,381	2,385
Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	232	318
Awards, granted (in shares)	86
Awards, vested (in shares)	(169)
Awards, forfeited (in shares)	(3)
Weighted-average grant-date fair value, outstanding beginning balance (in dollars per share)	$ 42.46
Weighted-average grant-date fair value, granted (in dollars per share)	78.07
Weighted-average grant-date fair value, vested (in dollars per share)	38.59
Weighted-average grant-date fair value, forfeited (in dollars per share)	54.32
Weighted-average grant-date fair value, outstanding ending balance (in dollars per share)	$ 56.72