Acquisitions - Solbar Industries Ltd. Acquisition (Details) (USD $)	12 Months Ended						0 Months Ended
	Aug. 31, 2013	Aug. 31, 2012	Aug. 31, 2011	Aug. 31, 2013 Ag Business	Aug. 31, 2012 Ag Business	Aug. 31, 2011 Ag Business	Feb. 09, 2012 Ag Business Solbar Industries Ltd. [Member]
Business Acquisition [Line Items]
Cash to receive for each outstanding share of Solbar, Right							$ 4.00
Payments to Acquire Businesses, Net of Cash Acquired	$ 12,711,000	$ 166,033,000	$ 67,489,000				$ 128,700,000
Cash acquired in acquisition							6,600,000
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Current assets							74,240,000
Investments							961,000
Property, plant and equipment							71,324,000
Goodwill	85,063,000	81,693,000	26,409,000	77,000,000	73,630,000	18,346,000	39,794,000
Definite-lived intangible assets							23,306,000
Current liabilities							(63,417,000)
Long-term debt							(15,849,000)
Other liabilities							(1,694,000)
Aggregate base purchase price							$ 128,665,000