Accumulated Other Comprehensive Income - Reclassifications (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	May 31, 2022	May 31, 2021	May 31, 2022	May 31, 2021
Accumulated other comprehensive income
Selling, general and administrative expenses	$ (13,807)	$ (13,969)	$ (40,307)	$ (38,560)
Amortization of prior pension service costs and unrecognized losses	1	1	3	3
Tax expense (benefit)	(3,803)	(3,454)	(10,434)	(10,288)
Net income (loss)	15,545	14,289	34,398	34,297
Reclassification out of accumulated other comprehensive income (loss)
Accumulated other comprehensive income
Net income (loss)	107	120	272	331
Gains on Restricted Investments: | Reclassification out of accumulated other comprehensive income (loss)
Accumulated other comprehensive income
Selling, general and administrative expenses	(6)	(5)	(86)	(54)
Tax expense (benefit)	1	1	22	14
Net income (loss)	(5)	(4)	(64)	(40)
Loss on Funded Pension Plan adjustments: | Reclassification out of accumulated other comprehensive income (loss)
Accumulated other comprehensive income
Amortization of prior pension service costs and unrecognized losses	149	165	447	495
Tax expense (benefit)	(37)	(41)	(111)	(124)
Net income (loss)	$ 112	$ 124	$ 336	$ 371