Restructuring and Impairment Costs (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Aug. 31, 2020	Nov. 30, 2020
Restructuring and Impairment Costs
Rotable asset impairment charges	$ 5.8	$ 7.0
Cost of sales and Selling, general and administrative expenses
Restructuring and Impairment Costs
Severance and furlough-related costs		8.2
Accounts liabilities
Restructuring and Impairment Costs
Liability for severance costs		$ 3.9

Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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Data Type:	xbrli:monetaryItemType
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Period Type:	duration