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. 28, 2023	Feb. 28, 2022	Feb. 28, 2023	Feb. 28, 2022
Numerator for earnings per share:
Net income attributable to RPM International Inc. stockholders		$ 26,974	$ 33,019	$ 327,331	$ 292,476
Less: Allocation of earnings and dividends to participating securities		(274)	(133)	(1,593)	(2,222)
Net income available to common shareholders - basic		26,700	32,886	325,738	290,254
Reverse: Allocation of earnings and dividends to participating securities			133	1,593	2,222
Net income available to common shareholders - diluted		$ 26,700	$ 33,019	$ 327,331	$ 292,476
Denominator for basic and diluted earnings per share:
Basic weighted average common shares		127,495	127,943	127,564	128,013
Average diluted options and awards		540	1,759	1,225	1,609
Total shares for diluted earnings per share	[1]	128,035	129,702	128,789	129,622
Earnings Per Share of Common Stock Attributable to RPM International Inc. Stockholders:
Basic Earnings Per Share of Common Stock		$ 0.21	$ 0.26	$ 2.55	$ 2.27
Method used to calculate basic earnings per share		Two-class	Two-class	Two-class	Two-class
Diluted Earnings Per Share of Common Stock		$ 0.21	$ 0.25	$ 2.54	$ 2.26
Method used to calculate diluted earnings per share		Two-class	Treasury	Treasury	Treasury

[1] 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. For the three and nine months ended February 28, 2022, approximately 320,000 and 655,000 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.