Accumulated Other Comprehensive Loss (Roll Forward of Balances in Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2020	Aug. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	$ (19,847)	$ (18,088)
Current period change	(725)	(1,759)
Balance	(20,572)	(19,847)
Defined Benefit Pension Plan Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(2,916)	(2,199)
Current period change	(312)	(717)
Balance	(3,228)	(2,916)
Defined Benefit Pension Plan Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(16,931)	(15,889)
Current period change	(499)	(1,042)
Balance	(17,430)	(16,931)
Unrealized Gains on Marketable Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	0	0
Current period change	86	0
Balance	$ 86	$ 0