Stock-Based Compensation - Stock Options (Details) - USD ($)	3 Months Ended
	Oct. 31, 2015	Oct. 31, 2014
Additional Disclosures
Targeted annual dividend per share (in dollars per share)	$ 1.20
Stock Options
Awards (in Shares)
Outstanding, Beginning Balance (in shares)	2,119,683
Granted (in shares)	480,265
Expired/canceled (in shares)	(182,250)
Exercised (in shares)	(19,200)
Outstanding, Ending Balance (in shares)	2,398,498
Exercisable, Ending Balance (in shares)	1,024,375
Vested and Expected to Vest, Ending Balance (in shares)	2,320,958
Weighted Average Exercise Price
Outstanding, Beginning Balance (in dollars per share)	$ 29.33
Granted (in dollars per share)	28.00
Expired/canceled (in dollars per share)	29.84
Exercised (in dollars per share)	27.24
Outstanding, Ending Balance (in dollars per share)	29.04
Exercisable, Ending Balance (in dollars per share)	28.43
Vested and Expected to Vest, Ending Balance (in dollars per share)	$ 29.03
Weighted Average Remaining Contractual Term (Years)
Outstanding, Ending Balance	7 years 1 month 20 days
Exercisable, Ending Balance	5 years 6 months 25 days
Vested And Expected To Vest, Ending Balance	7 years 1 month 5 days
Aggregate Intrinsic Value
Outstanding, Ending Balance	$ 0
Exercisable, Ending Balance	0
Vested and Expected to Vest, Ending Balance	$ 0
Additional Disclosures
Exercise price, lower range limit (in dollars per share)	$ 24.35
Exercise price, upper range limit (in dollars per share)	$ 33.94
Total intrinsic value of stock-based awards settled	$ 32,000	$ 1,153,000
Contractual term (in years)	10 years	10 years
Vesting period (in years)	5 years	5 years
Vested Stock Based Awards Net Settled Upon Exercise (in shares)	19,200	146,963
Stock Issued During The Period, Shares, Net Settlement Of Stock-Based Awards	706	32,073
Per share weighted average grant date fair value of stock based awards granted (in dollars per share)	$ 5.73	$ 5.94
Fair Value Assumptions
Expected dividend yield	4.29%	3.54%
Expected volatility	34.26%	27.00%
Risk-free interest rate	1.54%	1.76%
Expected life (years)	5 years 1 month 28 days	5 years 5 months 5 days