Other Assets - Rollforward of Capitalized Maintenance Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2019	Aug. 31, 2018	Aug. 31, 2017
Capitalized Maintenance Expense [Roll Forward]
Balance at Beginning of Year	$ 130,780	$ 105,006	$ 169,054
Cost Deferred	224,406	87,460	3,010
Amortization	(68,296)	(61,686)	(67,058)
Balance at End of Year	$ 286,890	$ 130,780	$ 105,006