Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Feb. 28, 2018	Feb. 28, 2017	Feb. 28, 2018	Feb. 28, 2017
Net income (loss)	$ 166,626	$ 14,973	$ 346,245	$ 223,915
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract]
Postretirement benefit plan activity, net of tax expense (benefit)	3,141	3,724	7,338	6,963
Unrealized net gain (loss) on available for sale investments, net of tax expense (benefit)	3,554	968	7,194	1,744
Cash flow hedges, net of tax expense (benefit)	1,063	963	1,059	1,618
Foreign currency translation adjustment, net of tax expense (benefit)	2,461	9,123	(146)	(10,041)
Other comprehensive income (loss), net of tax	10,219	14,778	15,445	284
Comprehensive income (loss)	176,845	29,751	361,690	224,199
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest	(48)	406	(512)	198
Comprehensive Income (Loss) Attributable to CHS	$ 176,893	$ 29,345	$ 362,202	$ 224,001