Contingent Liabilities and Commitments - Additional Informattion (Detail) $ in Thousands	Feb. 28, 2019 USD ($)
Tank Replacement Costs
Loss Contingencies [Line Items]
Best estimated probable costs charge to costs of goods sold	$ 13,000

Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

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Name:	us-gaap_LossContingencyEstimateOfPossibleLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant