Service Revenue (Summary of Changes in Deferred Revenue Related to Material Rights Performance Obligations) (Details) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Feb. 28, 2021 |
Feb. 29, 2020 |
Feb. 28, 2021 |
Feb. 29, 2020 |
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| Service Revenue [Abstract] | ||||
| Balance, beginning of period | $ 39.6 | $ 45.1 | $ 42.6 | $ 45.7 |
| Deferral of revenue | 6.9 | 7.4 | 16.6 | 20.3 |
| Recognition of unearned revenue | (6.7) | (7.4) | (19.4) | (20.9) |
| Balance, end of period | $ 39.8 | $ 45.1 | $ 39.8 | $ 45.1 |
| X | ||||||||||
- Definition Contract With Customer Liability Additions No definition available.
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| X | ||||||||||
- Definition Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- References No definition available.
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