Schedule of Share Based Compensation Stock Options Activity (Detail) (USD $)	12 Months Ended						12 Months Ended									12 Months Ended
	Aug. 31, 2012	Aug. 31, 2012 Minimum [Member]	Aug. 31, 2012 Maximum [Member]	Aug. 31, 2011 Outstanding Beginning Balance Option Price Range [Member]	Aug. 31, 2011 Outstanding Beginning Balance Option Price Range [Member] Minimum [Member]	Aug. 31, 2011 Outstanding Beginning Balance Option Price Range [Member] Maximum [Member]	Aug. 31, 2012 Granted During Period Option Price Range [Member]	Aug. 31, 2012 Granted During Period Option Price Range [Member] Minimum [Member]	Aug. 31, 2012 Granted During Period Option Price Range [Member] Maximum [Member]	Aug. 31, 2012 Cancelled During Period Option Price Range [Member]	Aug. 31, 2012 Cancelled During Period Option Price Range [Member] Minimum [Member]	Aug. 31, 2012 Cancelled During Period Option Price Range [Member] Maximum [Member]	Aug. 31, 2012 Outstanding Ending Balance Option Price Range [Member]	Aug. 31, 2012 Outstanding Ending Balance Option Price Range [Member] Minimum [Member]	Aug. 31, 2012 Outstanding Ending Balance Option Price Range [Member] Maximum [Member]	Aug. 31, 2012 Exercisable Ending Balance Option Price Range [Member]	Aug. 31, 2012 Exercisable Ending Balance Option Price Range [Member] Minimum [Member]	Aug. 31, 2012 Exercisable Ending Balance Option Price Range [Member] Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate Intrinsic value, Outstanding, Ending Balance													$ 1,360,000
Option Price Range, Outstanding Beginning of the period				$ 14.52	$ 4.66	$ 21.73								$ 4.66	$ 21.73
Aggregate Intrinsic value, Options Exercisable																$ 40,500
Options outstanding, end of period, Shares				1,333,885									1,824,916
Option Price Range, Granted							$ 5.61	$ 5.29	$ 5.65
Option Price Range, Exercised
Option Price Range, Cancelled										$ 13.61	$ 7.73	$ 17.50
Weighted Average Remaining Term, Outstanding, Ending Balance (in years)													3 years 11 months 19 days
Weighted Average Remaining Term, Options Exercisable (in years)																2 years 2 months 9 days
Option Price Range, Outstanding end of the period				$ 14.52	$ 4.66	$ 21.73							$ 10.94	$ 4.66	$ 21.73
Weighted-Average Exercise Price, Options Exercisable, end of period (in USD per share)																$ 14.88	$ 4.66	$ 21.73
Options Price Range, Exercisable end of period																$ 14.88	$ 4.66	$ 21.73
Options outstanding, beginning of period, Shares				1,333,885
Shares, Granted							760,500
Shares, Exercised	0
Shares, Cancelled										(269,469)
Options exercisable, end of period, Shares																1,050,916