v3.26.3
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, 2026
Aug. 31, 2025
Numerator for earnings per share:    
Net Income (Loss) $ 256,357 $ 227,605
Less: Allocation of earnings and dividends to participating securities (915) (885)
Net income available to common shareholders - basic 255,442 226,720
Add: Undistributed earnings reallocated to unvested shareholders 3 3
Net income available to common shareholders - diluted $ 255,445 $ 226,723
Denominator for basic and diluted earnings per share:    
Basic weighted average common shares 126,744 127,283
Average diluted options and awards 496 667
Total shares for diluted earnings per share [1] 127,240 127,950
Earnings Per Share of Common Stock Attributable to RPM International Inc. Stockholders:    
Basic Earnings Per Share of Common Stock $ 2.02 $ 1.78
Method used to calculate basic earnings per share Two-class Two-class
Diluted Earnings Per Share of Common Stock $ 2.01 $ 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 stock appreciation rights (“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, 2026 and 2025, approximately 860,000 and 400,000 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.