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, 2019	Aug. 31, 2018
Numerator for earnings per share:
Net income attributable to RPM International Inc. stockholders		$ 106,188	$ 69,764
Less: Allocation of earnings and dividends to participating securities		(623)	(611)
Net income available to common shareholders - basic		105,565	69,153
Add: Undistributed earnings reallocated to unvested shareholders		2	1
Add: Income effect of contingently issuable shares			1,480
Net income available to common shareholders - diluted		$ 105,567	$ 70,634
Denominator for basic and diluted earnings per share:
Basic weighted average common shares		128,882	131,861
Average diluted options and awards		622	636
Additional shares issuable assuming conversion of convertible securities	[1]		3,933
Total shares for diluted earnings per share	[2]	129,504	136,430
Earnings Per Share of Common Stock Attributable to RPM International Inc. Stockholders:
Basic Earnings Per Share of Common Stock		$ 0.82	$ 0.52
Diluted Earnings Per Share of Common Stock		$ 0.82	$ 0.52

[1] Represents the number of shares that would have been issued if our contingently convertible notes had been converted.  We included these shares in the calculation of diluted EPS as the conversion of the notes were eligible to be settled, at our election, in cash, shares of our common stock, or a combination of cash and shares of our common stock.  On November 27, 2018, we redeemed all of our 2.25% convertible senior notes due 2020, primarily for cash, but also issued 598,601 shares of our common stock in the transaction.

[2] Restricted shares totaling 178,000 and 126,750 for the three months ended August 31, 2019 and 2018, respectively, were excluded from the calculation of diluted earnings per share as their effect would have been anti-dilutive. In addition, stock appreciation rights (SARs) totaling  790,000 for the three months ended August 31, 2019 and 890,000 for the three months ended August 31, 2018, were excluded from the calculation of diluted earnings per share as their effect would have been anti-dilutive.