Equity - Restricted Stock (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
May 31, 2022	May 31, 2021	May 31, 2020
Selling, general and administrative expenses
Weighted Average Fair Value on Grant Date
Excess tax benefit recognized	$ 4.4	$ 5.2	$ 3.4
Restricted stock
Number of Shares
Nonvested at the beginning of the period ( in shares)	369,000
Granted (in shares)	336,000
Vested (in shares)	(127,000)
Forfeited (in shares)	(24,000)
Nonvested at the end of the period (in shares)	554,000	369,000
Weighted Average Fair Value on Grant Date
Nonvested at the beginning of the period (in dollars per share)	$ 30.12
Granted (in dollars per share)	46.44
Vested (in dollars per share)	32.30
Forfeited (in dollars per share)	43.30
Nonvested at the end of the period (in dollars per share)	$ 38.95	$ 30.12
Unearned compensation not yet recognized	$ 13.2
Average remaining expensed period of unearned compensation	0 years
Performance Based Restricted Stock \| Executives and other key employees
Number of Shares
Granted (in shares)	43,010	0	52,475
Time Based Restricted Stock \| Board of Directors
Number of Shares
Granted (in shares)	32,307	72,021	44,123
Time Based Restricted Stock \| Executives and other key employees
Number of Shares
Granted (in shares)	260,742	144,255	56,535

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of cash outflow for realized tax benefit related to deductible compensation cost reported on the entity's tax return for equity instruments in excess of the compensation cost for those instruments recognized for financial reporting purposes.

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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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The number of grants made 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).

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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).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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