Stock-Based Compensation - Summary of Activity under Company's Share-Based Compensation Plans (Detail) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
	Jan. 31, 2016	Jan. 31, 2015
Summary of Stock Option Activity [Abstract]
Options Outstanding at July 31, 2014	3,500,951
Options Outstanding at July 31, 2014, Weighted Average Exercise Price	$ 29.64
Options, Grants in Period	881,744
Options, Grants in Period, Weighted Average Exercise Price	$ 20.02	$ 22.70
Options, Exercised in Period	(2,454)
Options, Exercised in Period, Weighted Average Exercise Price	$ 21.73
Options, Forfeitures and Expirations in Period	(375,756)
Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price	$ 32.20
Options Outstanding at January 31, 2015	4,004,485
Options Outstanding at January 31, 2015, Weighted Average Exercise Price	$ 27.28
Options Outstanding, Exercisable	2,723,184	3,131,418
Options Outstanding, Exercisable, Weighted Average Exercise Price	$ 30.00	$ 30.97
Options Outstanding, Weighted Average Remaining Contractual Term	6 years
Options Outstanding, Aggregate Intrinsic Value	$ 1,898,393
Options Outstanding, Exercisable, Weighted Average Remaining Contractual Term	4 years 6 months
Options Outstanding, Exercisable, Aggregate Intrinsic Value	$ 183,307
Service Based Restricted Shares and Restricted Stock Units [Member]
Summary of Restricted Stock Unit and Restricted Share Activity [Abstract]
RSUs and Restricted Shares Outstanding at July 31, 2014	677,454
RSUs and Restricted Shares Outstanding at July 31, 2014, Weighted Average Grant Date Fair Value	$ 24.72
RSUs and Restricted Shares, Grants in Period	173,394
RSUs and Restricted Shares, Grants in Period, Weighted Average Grant Date Fair Value	$ 20.07
RSUs and Restricted Shares, Vested in Period	(72,164)
RSUs and Restricted Shares, Vested in Period, Weighted Average Grant Date Fair Value	$ 25.12
RSUs and Restricted Shares, Forfeited in Period	(41,869)
RSUs and Restricted Shares, Forfeitures, Weighted Average Grant Date Fair Value	$ 24.12
RSUs and Restricted Shares Outstanding at January 31, 2015	736,815
RSUs and Restricted Shares Outstanding at January 31, 2015, Weighted Average Grant Date Fair Value	$ 23.62