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Share Based Compensation Arrangement By Share Based Payment Award Options Expected To Vest Weighted Average Remaining Contractual Term

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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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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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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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Weighted average remaining contractual term for equity-based awards excluding options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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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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.

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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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Number of additional shares authorized for issuance under share-based payment arrangement.

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Number of shares authorized for issuance under share-based payment arrangement.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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Number of options outstanding, including both vested and non-vested options.

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Percentage of vesting of award under share-based payment arrangement.

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Intrinsic value of outstanding award under share-based payment arrangement. Excludes share and unit options.

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Expected term of 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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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions				1 Months Ended	12 Months Ended
	Jul. 18, 2019	Oct. 03, 2018	Oct. 10, 2003	Oct. 31, 2019	May 31, 2020	May 31, 2019	May 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value of options outstanding					$ 61.8
Weighted-average remaining contractual life of options outstanding					6 years 1 month 9 days
Aggregate intrinsic value of options exercisable					$ 46.6
Weighted-average remaining contractual life of options exercisable					4 years 10 months 6 days
Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incentive plan approval date					Oct. 09, 2014
2014 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unamortized stock-based compensation expense					$ 3.5
Shares of common stock authorized					6,000,000
Additional shares of common stock authorized				5,000,000
Shares of common stock available for grant				6,100,427
Directors Equity Incentive Plan 2003
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incentive plan approval date			Oct. 10, 2003
Share based compensation arrangement vesting period			3 years
Unamortized stock-based compensation expense					$ 1.9
Shares of common stock available for grant			500,000		7,200
Shares granted to Directors					$ 67.26	$ 60.50	$ 51.63
Shares granted					23,000
Shares of restricted stock vested					16,000
2007 Plan and 2014 Omnibus Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted to Directors					$ 62.17	$ 60.01	$ 55.19
Shares granted					30,185
Shares outstanding					446,000	432,000
Employee Incentive Plan 2007
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unamortized stock-based compensation expense					$ 0.6
Shares of common stock available for grant					0
SARs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock appreciation rights expected term					6 years 6 months	6 years 6 months	7 years
Unamortized stock-based compensation expense					$ 7.9
Unamortized stock-based compensation expense expected recognition period					2 years 3 months 18 days
Shares expected to vest					2,500,000
Shares expected to vest, weighted-average exercise price					$ 49.86
Shares expected to vest, weighted-average remaining contractual term					6 years 1 month 6 days
SARs \| Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock appreciation rights expected term					10 years
Share based compensation arrangement vesting period					4 years
Stock options outstanding					2,482,500
Full Value Stock Award \| 2014 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock authorized					3,000,000
Additional shares of common stock authorized				2,250,000
Performance Earned Restricted Stock Awards and Performance Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation arrangement vesting period					3 years
Unamortized stock-based compensation expense					$ 15.8
Shares granted to Directors					$ 63.52	$ 60.36	$ 52.26
Shares granted					405,000
Shares of restricted stock vested					361,000
2018 Contingent Performance Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unamortized stock-based compensation expense					$ 0.6
Unamortized stock-based compensation expense expected recognition period					1 year
Shares granted to Directors		$ 60.50
Shares granted		192,000
Performance goals attainment period for PSUs awards		3 years
Shares outstanding					168,000
2018 Contingent Performance Stock Units \| Earnings Before Interest Taxes
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		50.00%
2018 Contingent Performance Stock Units \| Earnings Before Interest Taxes Margin
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		50.00%
2018 Contingent Performance Stock Units \| Upon Achievement of Performance Goals \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		0.00%
2018 Contingent Performance Stock Units \| Upon Achievement of Performance Goals \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		200.00%
2019 Contingent Performance Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unamortized stock-based compensation expense					$ 3.3
Unamortized stock-based compensation expense expected recognition period					2 years
Shares granted to Directors	$ 62.17
Shares granted	178,000
Performance goals attainment period for PSUs awards	3 years
Shares outstanding					178,000
2019 Contingent Performance Stock Units \| Earnings Before Interest Taxes
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	50.00%
2019 Contingent Performance Stock Units \| Earnings Before Interest Taxes Margin
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	50.00%
2019 Contingent Performance Stock Units \| Upon Achievement of Performance Goals \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	0.00%
2019 Contingent Performance Stock Units \| Upon Achievement of Performance Goals \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	200.00%
Nonvested Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unamortized stock-based compensation expense					$ 25.7
Unamortized stock-based compensation expense expected recognition period					2 years 2 months 4 days
Shares granted to Directors					$ 63.62	$ 60.34	$ 52.62
Shares granted					458,000
Remaining weighted-average contractual term					2 years 2 months 4 days
Total fair value of shares vested					$ 20.8	$ 37.8	$ 29.9
Shares expected to vest					1,120,000
Shares expected to vest, weighted-average grant-date fair value					$ 58.03
Shares of restricted stock vested					421,000
Total intrinsic value of restricted shares converted					$ 26.8	$ 58.1	$ 7.6
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of restricted stock vested					420,571	832,717