Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions		1 Months Ended	12 Months Ended
	Oct. 10, 2003	Oct. 31, 2019	May 31, 2024	May 31, 2023	May 31, 2022	May 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding			1,990,000	2,288,000
Aggregate intrinsic value of options outstanding			$ 72.7
Weighted-average remaining contractual life of options outstanding			6 years 4 months 20 days
Aggregate intrinsic value of options exercisable			$ 52.1
Weighted-average remaining contractual life of options exercisable			5 years 2 months 15 days
Beginning balance			2,288,000
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]
Shares of common stock authorized			6,000,000
Additional shares of common stock authorized		5,000,000
Shares available for future issuance			0
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			$ 2.4
Weighted-average grant date fair value			$ 98.61	$ 92.87	$ 81.53
Shares granted			18,000
Shares of common stock available for grant	500,000
Shares of restricted stock vested			19,000
2007 Plan and 2014 Omnibus Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value			$ 93.51	$ 81.01	$ 86.93
Shares granted			25,643
Shares outstanding			384,000	390,000
Employee Incentive Plan 2007
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unamortized stock-based compensation expense			$ 4.6
Shares granted			0
Stock Appreciation Rights (SARs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock appreciation rights expected term			6 years	6 years	6 years
Unamortized stock-based compensation expense			$ 10.7
Unamortized stock-based compensation expense expected recognition period			2 years 5 months 23 days
Shares expected to vest			2,000,000
Shares expected to vest, weighted-average exercise price			$ 75.52
Shares vested or expected to vest, weighted-average remaining contractual term			6 years 4 months 17 days
Stock Appreciation Rights (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			1,989,900
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			$ 13.1
Weighted-average grant date fair value			$ 93.74		$ 81.03	$ 86.88
Shares granted			344,000
Shares of restricted stock vested			357,000
Performance Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance goals attainment period for PSUs awards			3 years
Performance Stock Units | Earnings Before Interest Taxes Margin
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			50.00%
Performance Stock Units | Upon Achievement of Performance Goals | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			0.00%
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			$ 29.9
Weighted-average grant date fair value			$ 93.95
Shares granted			388,000
Remaining weighted-average contractual term			2 years 5 months 19 days
Shares of restricted stock vested			421,000