Restatement of Previously Issued Financial Statements - Reconciliation of Sales and Cost of Sales (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Feb. 28, 2013	Feb. 29, 2012	Feb. 28, 2013	Feb. 29, 2012
Sales	$ 110,082	$ 103,477	$ 228,104	$ 211,645
Cost of sales	99,081	94,076	203,845	190,436
Industrial Ingredients [Member]
Sales	83,478	78,573	173,846	160,817
As Previously Reported [Member]
Sales	89,037	86,188	183,896	176,934
Cost of sales	78,036	76,787	159,637	155,725
As Previously Reported [Member] | Industrial Ingredients [Member]
Sales	62,433	61,284	129,638	126,106
Adjustment [Member]
Sales	21,045	17,289	44,208	34,711
Cost of sales	21,045	17,289	44,208	34,711
Adjustment [Member] | Industrial Ingredients [Member]
Sales	$ 21,045	$ 17,289	$ 44,208	$ 34,711