Stock-Based Compensation - Additional Information (Detail) (USD $)	12 Months Ended	1 Months Ended			12 Months Ended				1 Months Ended		12 Months Ended
	Aug. 31, 2013	Jan. 11, 2012 Carolina Starches, LLC [Member]	Jan. 26, 2012 2006 Incentive Plan [Member]	Aug. 31, 2013 2006 Incentive Plan [Member]	Aug. 31, 2013 Restricted Stock [Member]	Aug. 31, 2012 Restricted Stock [Member]	Aug. 31, 2011 Restricted Stock [Member]	Aug. 31, 2013 Restricted Stock [Member] Maximum [Member]	Jan. 01, 2013 Restricted Stock [Member] 2006 Incentive Plan [Member] Non Employee Directors [Member]	Jan. 26, 2012 Restricted Stock [Member] 2006 Incentive Plan [Member] Non Employee Directors [Member]	Aug. 31, 2013 Stock Options [Member]	Aug. 31, 2013 Stock Options [Member] 2006 Incentive Plan [Member]	Aug. 31, 2012 Stock Options [Member] 2006 Incentive Plan [Member]	Aug. 31, 2011 Stock Options [Member] 2006 Incentive Plan [Member]	Aug. 31, 2013 Stock Options [Member] 2006 Incentive Plan [Member] Vesting Period Two Years [Member]	Aug. 31, 2013 Stock Options [Member] 2006 Incentive Plan [Member] Vesting Period Three Years [Member]	Aug. 31, 2011 Stock Options [Member] 2006 Incentive Plan [Member] Vesting Period One Year [Member]	Aug. 31, 2011 Stock Options [Member] 2006 Incentive Plan [Member] Vesting Period Four Years [Member]	Aug. 31, 2013 Non Qualified Stock Options And Restricted Stock [Member] 2006 Incentive Plan [Member]	Aug. 31, 2013 Non Qualified Stock Options And Restricted Stock [Member] 2006 Incentive Plan [Member] Minimum [Member]	Aug. 31, 2013 Non Qualified Stock Options And Restricted Stock [Member] 2006 Incentive Plan [Member] Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of additional common shares authorized for issuance under the plan (in shares)			800,000
Number of common shares available for issuance under the plan				388,882
Vesting period (in Years)		2 years							1 year	1 year			3 years		2 years	3 years	1 year	4 years		1 year	4 years
Expiration period (in years)																			Seven years
Share price of Company's stock	$ 13.55
Intrinsic value of options exercised	$ 835,300
Options granted during the period		82,500										120,000	678,000	98,000	75,000	45,000	80,000	18,000
Option term		7 years
Compensation expense related to non-vested awards not yet recognized											900,000
Weighted-average period over which unrecognized compensation cost will be recognized (in years)					3 months 18 days						1 year 2 months 12 days
Total fair value of restricted stock vested					400,000	1,000,000	1,200,000
Number of shares issued for non-employee director, shares									2,721	3,539
Restricted stock awards granted					24,489		0
Compensation expense related to unvested awards not yet recognized								$ 100,000