Stock-Based Compensation - Schedule of Share Based Compensation Stock Options Activity (Detail) (USD $)	3 Months Ended		3 Months Ended
	Nov. 30, 2012	Aug. 31, 2012 Outstanding Beginning Balance Option Price Range [Member]	Nov. 30, 2012 Granted During Period Option Price Range [Member]	Nov. 30, 2012 Cancelled During Period Option Price Range [Member]	Nov. 30, 2012 Outstanding Ending Balance Option Price Range [Member]	Nov. 30, 2012 Exercisable Ending Balance Option Price Range [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding, beginning of period, Shares		1,824,916
Options outstanding, end of period, Shares		1,824,916			1,801,725
Shares, Granted			25,000
Weighted-Average Exercise Price, Options Outstanding end of period (in USD per share)		$ 10.94			$ 10.82
Shares, Exercised
Shares, Cancelled				(48,191)
Options exercisable, end of period, Shares						1,005,225
Weighted-Average Exercise Price, Options Outstanding beginning of period (in USD per share)		$ 10.94
Weighted-Average Exercise Price, Granted (in USD per share)			$ 7.60
Weighted-Average Exercise Price, Exercised (in USD per share)
Weighted-Average Exercise Price, Cancelled (in USD per share)				$ 13.92
Weighted-Average Exercise Price, Options Exercisable, end of period (in USD per share)						$ 14.90
Weighted Average Remaining Term, Outstanding, Ending Balance (in years)					3 years 10 months 10 days
Weighted Average Remaining Term, Options Exercisable (in years)						2 years 18 days
Aggregate Intrinsic value, Outstanding, Ending Balance					$ 1,394,000
Aggregate Intrinsic value, Options Exercisable						$ 50,300