Summary of Significant Accounting Policies - Property, Plant and Equipment and Investments (Details) - USD ($) $ in Millions	12 Months Ended
May 31, 2021	May 31, 2020
Investments
Rotable asset impairment charges	$ 9.1	$ 8.1
Future rent due to us under non-cancelable leases
2022	21.0
2023	21.7
2024	21.1
2025	21.1
2026	$ 19.1
Building and improvements \| Minimum
Property, Plant and Equipment
Useful life	10 years
Building and improvements \| Maximum
Property, Plant and Equipment
Useful life	40 years
Equipment \| Minimum
Property, Plant and Equipment
Useful life	3 years
Equipment \| Maximum
Property, Plant and Equipment
Useful life	10 years
Furniture and fixtures \| Minimum
Property, Plant and Equipment
Useful life	3 years
Furniture and fixtures \| Maximum
Property, Plant and Equipment
Useful life	10 years
Capitalized software \| Minimum
Property, Plant and Equipment
Useful life	3 years
Capitalized software \| Maximum
Property, Plant and Equipment
Useful life	10 years
Rotable assets
Investments
Rotable asset impairment charges	$ 5.8	$ 1.9
Additional impairment charges	1.4
Manufacturing facilities
Investments
Impairment and related charges	$ 2.6

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Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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Amount of lease payment to be received by lessor for operating lease in fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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