Earnings Per Share - Reconciliation of Numerator and Denominator of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		12 Months Ended
		May 31, 2024	May 31, 2023	May 31, 2022
Numerator for earnings per share:
Net Income (Loss)		$ 588,397	$ 478,691	$ 491,481
Less: Allocation of earnings and dividends to participating securities		(2,630)	(2,156)	(3,924)
Net income available to common shareholders - basic		585,767	476,535	487,557
Reverse: Allocation of earnings and dividends to participating securities		0	2,156	3,924
Add: Undistributed earnings reallocated to unvested shareholders		8	0	0
Net income available to common shareholders - diluted		$ 585,775	$ 478,691	$ 491,481
Denominator for basic and diluted earnings per share:
Basic weighted average common shares		127,767	127,507	127,948
Average diluted options and awards		573	1,309	1,632
Total shares for diluted earnings per share	[1]	128,340	128,816	129,580
Earnings Per Share of Common Stock Attributable to RPM International Inc. Stockholders:
Basic Earnings Per Share of Common Stock		$ 4.58	$ 3.74	$ 3.81
Method used to calculate basic earnings per share		Two-Class	Two-Class	Two-Class
Diluted Earnings Per Share of Common Stock		$ 4.56	$ 3.72	$ 3.79
Method used to calculate diluted earnings per share		Two-Class	Treasury	Treasury

[1] The dilutive effect of performance-based restricted stock units is included when they have met minimum performance thresholds. The dilutive effect of SARs includes all outstanding awards except awards that are considered antidilutive. SARs are antidilutive when the exercise price exceeds the average market price of the Company’s common shares during the periods presented. For the years ended May 31, 2024, 2023 and 2022, approximately 260,000, 750,000 and 655,000 shares of stock, respectively, granted under stock-based compensation plans were excluded from the calculation of diluted EPS, as the effect would have been anti-dilutive.