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, 2017	Feb. 29, 2016	Feb. 28, 2017	Feb. 29, 2016
Numerator for earnings per share:
Net income attributable to RPM International Inc. stockholders		$ 11,928	$ 18,582	$ 53,771	$ 201,830
Less: Allocation of earnings and dividends to participating securities		(232)	(316)	(847)	(3,375)
Net income available to common shareholders - basic		11,696	18,266	52,924	198,455
Reverse: Allocation of earnings and dividends to participating securities					3,375
Add: Income effect of contingently issuable shares					4,067
Net income available to common shareholders - diluted		$ 11,696	$ 18,266	$ 52,924	$ 205,897
Denominator for basic and diluted earnings per share:
Basic weighted average common shares		130,677	129,068	130,657	129,506
Average diluted options					3,456
Additional shares issuable assuming conversion of convertible securities	[1]				3,886
Total shares for diluted earnings per share	[2]	130,677	129,068	130,657	136,848
Earnings per Share of Common Stock Attributable to RPM International Inc. Stockholders:
Basic Earnings Per Share of Common Stock		$ 0.09	$ 0.14	$ 0.41	$ 1.53
Diluted Earnings Per Share of Common Stock		$ 0.09	$ 0.14	$ 0.41	$ 1.50

[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 1,676,404 and 919,918 for the three and nine months ended February 29, 2016, 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 nine months ended February 28, 2017. In addition, stock appreciation rights (SARs) totaling 600,000 for the three and nine months ended February 28, 2017 and 1,140,000 for the three and nine months ended February 29, 2016 were excluded from the calculation of diluted earnings per share as their effect would have been anti-dilutive.