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
		Aug. 31, 2025	Feb. 28, 2025	Aug. 31, 2024
Numerator for earnings per share:
Net Income (Loss)		$ 227,605		$ 227,692
Less: Allocation of earnings and dividends to participating securities		(885)		(893)
Net income available to common shareholders - basic		226,720		226,799
Add: Undistributed earnings reallocated to unvested shareholders		3		4
Net income available to common shareholders - diluted		$ 226,723		$ 226,803
Denominator for basic and diluted earnings per share:
Basic weighted average common shares		127,283		127,691
Average diluted options and awards		667		729
Total shares for diluted earnings per share	[1]	127,950		128,420
Earnings Per Share of Common Stock Attributable to RPM International Inc. Stockholders:
Basic Earnings Per Share of Common Stock		$ 1.78	$ 1.78	$ 1.78
Method used to calculate basic earnings per share		Two-class		Two-class
Diluted Earnings Per Share of Common Stock		$ 1.77	$ 1.77	$ 1.77
Method used to calculate diluted earnings per share		Two-class		Two-class

[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 three months ended August 31, 2025 and 2024, approximately 400,000 and 180,000 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.