Stock-Based Compensation Plans (Other Information Pertaining to Restricted Stock Awards) (Details) - USD ($) $ / shares in Units, $ in Millions |
12 Months Ended | |||||
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May 31, 2020 |
May 31, 2019 |
May 31, 2018 |
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| Time-Based Restricted Stock Awards [Member] | ||||||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||||
| Weighted-average grant-date fair value per share | $ 84.46 | $ 69.80 | $ 57.50 | |||
| Total grant-date fair value of shares vested | $ 3.2 | $ 3.0 | $ 3.0 | |||
| Performance-Based Restricted Stock Awards [Member] | ||||||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||||
| Weighted-average grant-date fair value per share | $ 80.59 | [1] | $ 65.17 | $ 53.08 | ||
| Total grant-date fair value of shares vested | $ 5.8 | $ 5.3 | $ 6.6 | |||
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- Definition The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition 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. No definition available.
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