Derivative Financial Instruments and Hedging Activities - Commodity Derivatives (Details) - Commodity derivatives - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	May 31, 2020	May 31, 2019	May 31, 2020	May 31, 2019
Cost of goods sold
Derivative [Line Items]
Pretax gains (losses) reclassified from AOCI related to cash flow hedges	$ 884	$ 1,810	$ 7,862	$ 9,812
Cash Flow Hedging
Derivative [Line Items]
Pretax gains (losses) recorded in OCI related to cash flow hedges	$ 11,081	$ (21,029)	$ (4,153)	$ (9,323)