Stock-Based Compensation Performance Shares, RSUs, Restricted Stock and Share Unit Awards (Details) - USD ($)	12 Months Ended
	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014
Additional Disclosures
Cash payments to remit employee's minimum statutory withholding requirements related to the net settlement of stock-based awards	$ 105,000	$ 473,000	$ 1,151,000
Dividend Equivalents [Abstract]
Accrued during the period	155,000	224,000	$ 113,000
Carrying value at period end	$ 450,795,000	$ 72,468,000
Performance Shares, RSUs, Restricted Stock and Share Units [Member]
Awards (In Shares)
Outstanding, Beginning Balance (in shares)	224,165	180,097	102,334
Granted (in shares)	71,605	66,294	95,326
Converted to common stock (in shares)	(16,439)	(18,422)	(7,857)
Forfeited (in shares)	(62,118)	(3,804)	(9,706)
Outstanding, Ending Balance (in shares)	217,213	224,165	180,097
Vested, Ending Balance (in shares)	35,855
Vested and Expected to Vest, Ending Balance (in shares)	209,521
Weighted Average Grant Date Fair Value
Outstanding, Beginning Balance (in dollars per share)	$ 28.26	$ 26.20	$ 25.80
Granted (in dollars per share)	27.45	33.96	26.48
Converted to common stock (in dollars per share)	26.35	27.79	26.18
Forfeited (in dollars per share)	27.62	32.47	24.83
Outstanding, Ending Balance (in dollars per share)	28.32	$ 28.26	$ 26.20
Vested, Ending Balance (in dollars per share)	27.24
Vested and Expected to Vest, Ending Balance (in dollars per share)	$ 28.26
Aggregate Intrinsic Value
Outstanding, Ending Balance	$ 2,839,000
Vested, Ending Balance	469,000
Vested and Expected to Vest, Ending Balance	2,738,000
Additional Disclosures
Total intrinsic value relating to fully vested stock-based awards converted during the period	$ 660,000
Performance Shares [Member] | Employees [Member] | Granted prior to fiscal 2014 [Member]
Additional Disclosures
Vesting period (in years)	5 years 3 months 19 days
Performance Shares [Member] | Employees [Member] | Granted Since Fiscal 2014 [Member]
Additional Disclosures
Performance period (in years)	3 years
RSUs and restricted stock [Member] | Non-Employee Director [Member]
Additional Disclosures
Vesting period (in years)	3 years
RSUs and restricted stock [Member] | Employees [Member]
Additional Disclosures
Vesting period (in years)	5 years
Dividend Equivalents [Member]
Dividend Equivalents [Abstract]
Accrued during the period	$ 155,000	$ 224,000	$ 113,000
Paid during the period	23,000	15,000	$ 4,000
Carrying value at period end	$ 457,000	$ 325,000