Stock-Based Compensation (Performance Shares, RSUs, Restricted Stock and Share Unit Awards) (Details)		12 Months Ended
	Jul. 31, 2017 $ / shares shares	Jul. 31, 2020 USD ($) $ / shares shares	Jul. 31, 2019 USD ($) $ / shares shares	Jul. 31, 2018 USD ($) $ / shares shares	Jul. 31, 2016
Dividend Equivalents [Abstract]
Accrued during the period | $		$ 294,000	$ 327,000	$ 300,000
Carrying value at period end | $		380,348,000	352,629,000
Income tax benefit from settlement of stock-based awards | $		$ 224,000	$ 479,000	$ 1,193,000
Performance Shares, RSUs, Restricted Stock and Share Units
Awards (In Shares)
Outstanding, Beginning Balance (in shares)		954,676	818,438	830,197
Granted (in shares)		560,361	442,363	473,005
Settled (in shares)		(431,581)	(275,619)	(354,822)
Forfeited (in shares)		(83,882)	(30,506)	(129,942)
Outstanding, Ending Balance (in shares)	830,197	999,574	954,676	818,438
Vested, Ending Balance (in shares)		429,191
Vested and Expected to Vest, Ending Balance (in shares)		964,807
Weighted Average Grant Date Fair Value
Outstanding, Beginning Balance (in dollars per share) | $ / shares		$ 22.40	$ 19.78	$ 16.95
Granted (in dollars per share) | $ / shares		19.93	29.76	22.45
Settled (in dollars per share) | $ / shares		22.02	26.05	17.66
Forfeited (in dollars per share) | $ / shares		22.84	25.52	17.26
Outstanding, Ending Balance (in dollars per share) | $ / shares	$ 16.95	21.15	$ 22.40	$ 19.78
Vested, Ending Balance (in dollars per share) | $ / shares		16.22
Vested and Expected to Vest, Ending Balance (in dollars per share) | $ / shares		$ 21.10
Aggregate Intrinsic Value
Outstanding, Ending Balance | $		$ 16,413,000
Vested, Ending Balance | $		7,047,000
Vested and Expected to Vest, Ending Balance | $		15,842,000
Additional Disclosures
Total intrinsic value relating to fully vested stock-based awards converted during the period | $		$ 9,635,000	$ 8,772,000	$ 10,473,000
Performance shares | Employees | Granted since fiscal 2014
Additional Disclosures
Performance period (in years)		3 years
RSUs and restricted stock | Employees
Additional Disclosures
Vesting period (in years)		5 years
Common stock, conversion ratio (in shares)		1
RSUs and restricted stock | Non-Employee Director
Additional Disclosures
Vesting period (in years)		5 years		3 years
Common stock, conversion ratio (in shares)				1
Share units
Awards (In Shares)
Granted (in shares)		330,696
Additional Disclosures
Common stock, conversion ratio (in shares)					1
Conversion period of vested share units	1 year
Granted units converted into common stock (in shares)		223,739
Number of shares issued as result of conversion		81,507
Number of units settled to date (in shares)		658,583
Dividend equivalents
Dividend Equivalents [Abstract]
Accrued during the period | $		$ 294,000	327,000	$ 300,000
Paid during the period | $		288,000	263,000	$ 141,000
Carrying value at period end | $		$ 783,000	$ 777,000