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		9 Months Ended
		Feb. 29, 2024	Feb. 28, 2023	Feb. 29, 2024	Feb. 28, 2023
Numerator for earnings per share:
Net income attributable to RPM International Inc. stockholders		$ 61,199	$ 26,974	$ 407,786	$ 327,331
Less: Allocation of earnings and dividends to participating securities		(279)	(274)	(1,840)	(1,593)
Net income available to common shareholders - basic		60,920	26,700	405,946	325,738
Reverse: Allocation of earnings and dividends to participating securities		0	0	0	1,593
Add: Undistributed earnings reallocated to unvested shareholders		0	0	5	0
Net income available to common shareholders - diluted		$ 60,920	$ 26,700	$ 405,951	$ 327,331
Denominator for basic and diluted earnings per share:
Basic weighted average common shares		127,781	127,495	127,803	127,564
Average diluted options and awards		553	540	512	1,225
Total shares for diluted earnings per share	[1]	128,334	128,035	128,315	128,789
Earnings Per Share of Common Stock Attributable to RPM International Inc. Stockholders:
Basic Earnings Per Share of Common Stock		$ 0.48	$ 0.21	$ 3.18	$ 2.55
Method used to calculate basic earnings per share		Two-class	Two-class	Two-class	Two-class
Diluted Earnings Per Share of Common Stock		$ 0.47	$ 0.21	$ 3.16	$ 2.54
Method used to calculate diluted earnings per share		Two-class	Two-class	Two-class	Treasury

[1] For the three and nine months ended February 29, 2024, approximately 300,000 and 250,000 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 nine months ended February 28, 2023, approximately 680,000 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.