Commitments and Contingencies (Summary of Undiscounted Environmental Remediation Liability Classifications) (Details) - USD ($) $ in Thousands	May 31, 2020	Aug. 31, 2019	May 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Other current liabilities	$ 1,182	$ 1,243	$ 1,243
Other noncurrent liabilities	14,257	14,674	14,871
Total environmental remediation liabilities	$ 15,439	$ 15,917	$ 16,114

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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