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, 2016	Nov. 30, 2015	Nov. 30, 2016	Nov. 30, 2015
Numerator for earnings per share:
Net income (loss) attributable to RPM International Inc. stockholders		$ (70,926)	$ 83,433	$ 41,843	$ 183,248
Less: Allocation of earnings and dividends to participating securities			(1,571)	(621)	(3,068)
Net income (loss) available to common shareholders – basic		(70,926)	81,862	41,222	180,180
Reverse: Allocation of earnings and dividends to participating securities			1,571		3,068
Add: Income effect of contingently issuable shares			1,354		2,706
Net income (loss) available to common shareholders – diluted		$ (70,926)	$ 84,787	$ 41,222	$ 185,954
Denominator for basic and diluted earnings per share:
Basic weighted average common shares		130,695	129,398	130,647	129,723
Average diluted options			3,453		3,466
Additional shares issuable assuming conversion of convertible securities	[1]		3,883		3,883
Total shares for diluted earnings per share	[2]	130,695	136,734	130,647	137,072
Earnings (Loss) Per Share of Common Stock Attributable to RPM International Inc. Stockholders:
Basic Earnings (Loss) Per Share of Common Stock		$ (0.54)	$ 0.63	$ 0.32	$ 1.39
Diluted Earnings (Loss) Per Share of Common Stock		$ (0.54)	$ 0.62	$ 0.32	$ 1.36

[1] Represents the number of shares that would be issued if our contingently convertible notes were converted. We include these shares in the calculation of diluted EPS as the conversion of the notes may be settled, at our election, in cash, shares of our common stock, or a combination of cash and shares of our common stock.

[2] Restricted shares totaling 1,169,393 and 919,918 for the three and six months ended November 30, 2015, respectively, were excluded from the calculation of diluted earnings per share because the grant price of the restricted shares exceeded the average market price of the shares during the period and their effect, accordingly, would have been anti-dilutive. There were no restricted shares identified as being anti-dilutive for the three and six months ended November 30, 2016. In addition, stock appreciation rights (SARs) totaling 1,400,000 for the three and six months ended November 30, 2015 were excluded from the calculation of diluted earnings per share as their effect would have been anti-dilutive.