Restatement of Previously Issued Financial Statements - Reconciliation of Sales and Cost of Sales (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	May 31, 2013	May 31, 2012	May 31, 2013	May 31, 2012
Sales	$ 121,719	$ 111,283	$ 349,823	$ 322,928
Cost of sales	108,528	99,829	312,373	290,265
Industrial Ingredients [Member]
Sales	93,184	85,110	267,030	245,927
As Previously Reported [Member]
Sales		92,924		269,858
Cost of sales		81,470		237,195
As Previously Reported [Member] | Industrial Ingredients [Member]
Sales		66,751		192,857
Adjustment [Member]
Sales		18,359		53,070
Cost of sales		18,359		53,070
Adjustment [Member] | Industrial Ingredients [Member]
Sales		$ 18,359		$ 53,070