Stock Option and Restricted Stock Awards Transactions (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Jul. 31, 2014		Jul. 31, 2013
Outstanding Stock Awards
Number of Shares
Outstanding at beginning period	367,997
Granted	108,139
Exercised	(86,141)
Vesting of restricted stock
Cancelled (forfeited and expired)	(8,205)
Outstanding at end period	381,790		367,997
Options vested or expected to vest at end period	370,851	[1]
Options exercisable at end period	170,334
Weighted Average Exercise Price
Outstanding at beginning period	$ 58.84
Granted	$ 77.14
Exercised	$ 60.53
Vesting of restricted stock
Cancelled (forfeited and expired)	$ 75.36
Outstanding at end period	$ 63.21		$ 58.84
Options vested or expected to vest at end period	$ 62.87	[1]
Options exercisable at end period	$ 55.23
Weighted Average Remaining Contractual Term (Years)
Outstanding at end period	4 years 9 months		4 years 9 months 22 days
Outstanding at end period	4 years 9 months		4 years 9 months 22 days
Options vested or expected to vest at end period	4 years 8 months 16 days	[1]
Options exercisable at end period	3 years 7 months 17 days
Aggregate Intrinsic Value
Outstanding at beginning period	$ 4,746
Outstanding at end period	3,940		4,746
Options vested or expected to vest at end period	3,926	[1]
Options exercisable at end period	$ 2,874
Time Based Restricted Stock
Number of Shares/Units
Outstanding at beginning period	198,441
Granted	32,700
Exercised
Vesting of restricted stock	(73,986)
Cancelled (forfeited and expired)	(13,798)
Outstanding at end period	143,357
Weighted Average Grant Date Fair Value
Outstanding at beginning period	$ 60.10
Granted	$ 82.46
Exercised
Vesting of restricted stock	$ 50.31
Cancelled (forfeited and expired)	$ 71.99
Outstanding at end period	$ 74.25
Performance awards
Number of Shares/Units
Outstanding at beginning period	329,066	[2]
Granted	138,291	[2]
Exercised		[2]
Vesting of restricted stock	(252,420)	[2]
Cancelled (forfeited and expired)	(27,007)	[2]
Outstanding at end period	187,930	[2]
Weighted Average Grant Date Fair Value
Outstanding at beginning period	$ 60.16
Granted	$ 65.66
Exercised
Vesting of restricted stock	$ 44.72
Cancelled (forfeited and expired)	$ 58.01
Outstanding at end period	$ 85.25

[1] In addition to the vested options, we expect a portion of the unvested options to vest at some point in the future. Stock options expected to vest are calculated by applying an estimated forfeiture rate to the unvested options.

[2] The performance-based unvested restricted stock is shown in this table at target, except for the number of shares vested, which reflect the shares earned. As of July 31, 2014, the maximum number of performance-based unvested restricted stock available to be earned is 375,860.