Commitments and Contingencies Schedule of Environmental Liabilities (Details) - USD ($) $ in Thousands	6 Months Ended
	Feb. 28, 2018	Aug. 31, 2017
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning Balance	$ 48,398
Liabilities Established (Released), Net	7,651
Payments and Other	(1,597)
Ending Balance	54,452
Short-Term	6,537	$ 2,007
Long-Term	$ 47,915	$ 46,391