Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2022	Aug. 31, 2021	Aug. 31, 2020
Accumulated other comprehensive income
Balance	$ 344,324	$ 302,792	$ 271,227
Total other comprehensive income (loss)	(9,157)	1,882	2,620
Balance	372,829	344,324	302,792
Accumulated Other Comprehensive Income (loss)
Accumulated other comprehensive income
Balance	(11,210)	(13,092)	(14,324)
Other comprehensive gains (losses) before reclassifications	(9,534)	1,433
Reclassifications to net income of previously deferred (gains) losses	377	449
Total other comprehensive income (loss)	(9,157)	1,882
Balance	(20,367)	(11,210)	(13,092)
Gains on Restricted Investments:
Accumulated other comprehensive income
Balance	518	269
Other comprehensive gains (losses) before reclassifications	(282)	297
Reclassifications to net income of previously deferred (gains) losses	(72)	(48)
Total other comprehensive income (loss)	(354)	249
Balance	164	518	269
Loss on Funded Pension Plan adjustments:
Accumulated other comprehensive income
Balance	(7,979)	(8,317)
Other comprehensive gains (losses) before reclassifications	330	(159)
Reclassifications to net income of previously deferred (gains) losses	449	497
Total other comprehensive income (loss)	779	338
Balance	(7,200)	(7,979)	(8,317)
Foreign Currency Translation Adjustment
Accumulated other comprehensive income
Balance	(3,749)	(5,044)
Other comprehensive gains (losses) before reclassifications	(9,582)	1,295
Total other comprehensive income (loss)	(9,582)	1,295
Balance	$ (13,331)	$ (3,749)	$ (5,044)