Commitments and Contingencies (Summary of Undiscounted Environmental Remediation Liability Classifications) (Details) - USD ($) $ in Thousands	Feb. 28, 2019	Aug. 31, 2018	Feb. 28, 2018
Commitments And Contingencies Disclosure [Abstract]
Other current liabilities	$ 1,243	$ 1,264	$ 1,544
Other noncurrent liabilities	14,993	15,319	15,677
Total environmental remediation liabilities	$ 16,236	$ 16,583	$ 17,221

Carrying value of the obligation (known or estimated) arising from requirements to perform activities to remediate one or more sites, payable in twelve months or in the next operating cycle if longer.

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