Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2019	Aug. 31, 2018	Aug. 31, 2017
Accumulated other comprehensive income
Balance at the beginning of the period	$ (12,336)	$ (13,469)
Other comprehensive gains (losses) before reclassifications	(3,134)	506
Reclassifications to net income of previously deferred (gains) losses	1,146	627
Total other comprehensive (loss) income	(1,988)	1,133	$ 2,010
Balance at the ending of the period	(14,324)	(12,336)	(13,469)
Restricted investments
Accumulated other comprehensive income
Balance at the beginning of the period	126	121
Other comprehensive gains (losses) before reclassifications	36	77
Reclassifications to net income of previously deferred (gains) losses	(8)	(72)
Total other comprehensive (loss) income	28	5
Balance at the ending of the period	154	126	121
Change in funded status of pension plans
Accumulated other comprehensive income
Balance at the beginning of the period	(5,796)	(6,181)
Other comprehensive gains (losses) before reclassifications	(1,629)	(314)
Reclassifications to net income of previously deferred (gains) losses	1,154	699
Total other comprehensive (loss) income	(475)	385
Balance at the ending of the period	(6,271)	(5,796)	(6,181)
Foreign currency translation adjustment
Accumulated other comprehensive income
Balance at the beginning of the period	(6,666)	(7,409)
Other comprehensive gains (losses) before reclassifications	(1,541)	743
Total other comprehensive (loss) income	(1,541)	743
Balance at the ending of the period	$ (8,207)	$ (6,666)	$ (7,409)