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		3 Months Ended		6 Months Ended
		Nov. 30, 2023	Nov. 30, 2022	Nov. 30, 2023	Nov. 30, 2022
Numerator for earnings per share:
Net income attributable to RPM International Inc. stockholders		$ 145,505	$ 131,344	$ 346,587	$ 300,357
Less: Allocation of earnings and dividends to participating securities		(707)	(676)	(1,597)	(1,466)
Net income available to common shareholders - basic		144,798	130,668	344,990	298,891
Reverse: Allocation of earnings and dividends to participating securities		0	676	0	1,466
Add: Undistributed earnings reallocated to unvested shareholders		2	0	4	0
Net income available to common shareholders - diluted		$ 144,800	$ 131,344	$ 344,994	$ 300,357
Denominator for basic and diluted earnings per share:
Basic weighted average common shares		127,758	127,585	127,816	127,600
Average diluted options and awards		491	1,326	496	1,287
Total shares for diluted earnings per share	[1]	128,249	128,911	128,312	128,887
Earnings Per Share of Common Stock Attributable to RPM International Inc. Stockholders:
Basic Earnings Per Share of Common Stock		$ 1.13	$ 1.02	$ 2.7	$ 2.34
Method used to calculate basic earnings per share		Two-class	Two-class	Two-class	Two-class
Diluted Earnings Per Share of Common Stock		$ 1.13	$ 1.02	$ 2.69	$ 2.33
Method used to calculate diluted earnings per share		Two-class	Treasury	Two-class	Treasury

[1] For the three and six months ended November 30, 2023, approximately 360,000 and 280,000 shares of stock granted under stock-based compensation plans were excluded from the calculation of diluted EPS, as the effect would have been anti-dilutive. For the three and six months ended November 30, 2022, approximately 700,000 and 720,000 shares of stock granted under stock-based compensation plans were excluded from the calculation of diluted EPS, as the effect would have been anti-dilutive.