Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Aug. 31, 2021	Aug. 31, 2020
Deferred tax assets:
Accrued expenses	$ 57,245	$ 51,560
Postretirement health care and deferred compensation	42,217	42,898
Tax credit carryforwards	128,824	123,193
Loss carryforwards	115,327	116,741
Nonqualified equity	391,309	344,924
Deferred tax asset lease obligation	62,770	64,140
Other	92,325	85,856
Deferred tax assets valuation allowance	(208,810)	(219,891)
Total deferred tax assets	681,207	609,421
Deferred tax liabilities:
Pension	24,277	17,131
Investments	110,910	95,916
Property, plant and equipment	557,129	556,160
Deferred tax liability right of use asset	61,870	64,140
Other	28,549	15,417
Total deferred tax liabilities	782,735	748,764
Deferred Tax Liabilities, Net	$ 101,528	$ 139,343