Earnings Per Share and Dividends (Earnings Per Share) (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	May 31, 2021	May 31, 2020	May 31, 2021	May 31, 2020
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common shares excluded from computation of diluted earnings per share (in shares)	665	3,717	665	3,379
Employee stock purchase plan
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common shares excluded from computation of diluted earnings per share (in shares)	0	57	0	92
Stock appreciation rights
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common shares excluded from computation of diluted earnings per share (in shares)	0	5	0	28