Stock-Based Compensation Stock Options (Details) - USD ($)	12 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2016
Additional Disclosures
Common stock issued for net settlement of stock-based awards (in shares)	8,706
Stock options
Awards (In Shares)
Outstanding, Beginning Balance (in shares)	1,855,875	2,256,679	2,119,683
Granted (in shares)	0	0	552,806
Expired/canceled (in shares)	(72,190)	(400,804)	(396,610)
Exercised (in shares)	(114,710)	0	(19,200)
Outstanding, Ending Balance (in shares)	1,668,975	1,855,875	2,256,679
Exercisable, Ending Balance (in shares)	1,314,448
Vested and Expected to Vest, Ending Balance (in shares)	1,632,696
Weighted Average Exercise Price (Per Share)
Outstanding, Beginning Balance (in dollars per share)	$ 28.60	$ 28.87	$ 29.33
Granted (in dollars per share)			27.15
Expired/canceled (in dollars per share)	27.58	30.15	28.99
Exercised (in dollars per share)	27.44		27.24
Outstanding, Ending Balance (in dollars per share)	28.72	$ 28.60	$ 28.87
Exercisable, Ending Balance (in dollars per share)	28.67
Vested and Expected to Vest, Ending Balance (in dollars per share)	$ 28.70
Weighted Average Remaining Contractual Term (Years)
Outstanding, Ending Balance	4 years 6 months 10 days
Exercisable, Ending Balance	4 years 24 days
Vested And Expected To Vest, Ending Balance	4 years 5 months 24 days
Aggregated Intrinsic Value
Outstanding, Ending Balance	$ 8,198,000
Exercisable, Ending Balance	6,516,000
Vested and Expected to Vest, Ending Balance	$ 8,049,000
Additional Disclosures
Exercise price, lower range limit (in dollars per share)	$ 20.90
Exercise price, upper range limit (in dollars per share)	$ 33.94
Total intrinsic value relating to stock-based awards exercised during the period	$ 469,000		$ 32,000
Vested stock-based awards net settled upon exercise (in shares)	101,610
Per share weighted average grant date fair value of stock based awards granted (in dollars per share)			$ 5.50
Fair Value Assumptions
Expected dividend yield			4.46%
Expected volatility			34.44%
Risk-free interest rate			1.52%
Expected life (years)			5 years 1 month 24 days
Stock options | Stock-based Awards with Five Year Contractual Term
Additional Disclosures
Contractual term (in years)			5 years
Vesting period (in years)			3 years
Stock options | Stock-based Awards with Ten Year Contractual Term
Additional Disclosures
Contractual term (in years)			10 years
Vesting period (in years)			5 years