Stock-Based Compensation Plans (Total Cost Of Share-Based Compensation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2020	Aug. 31, 2019	Aug. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost	$ (573)	$ 4,789	$ 2,846
Performance Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost	(1,518)	3,853	2,034
Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost	700	700	642
Compensation Cost Of The ESPP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost	185	176	155
Fully Vested Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost	$ 60	$ 60	$ 15