Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Nov. 30, 2018	Nov. 30, 2017	Nov. 30, 2018	Nov. 30, 2017
Income Statement [Abstract]
Net Sales		$ 1,362,531	$ 1,315,416	$ 2,822,520	$ 2,660,810
Cost of Sales		824,562	764,401	1,690,509	1,537,787
Gross Profit		537,969	551,015	1,132,011	1,123,023
Selling, General and Administrative Expenses		430,080	419,599	889,822	814,008
Restructuring Charges		7,724		27,800
Interest Expense		23,127	26,396	47,533	53,169
Investment Expense (Income), Net		7,033	(3,739)	4,600	(8,192)
Other Expense (Income), Net		3,412	(422)	3,725	(427)
Income Before Income Taxes		66,593	109,181	158,531	264,465
Provision for Income Taxes		17,420	13,323	39,172	51,704
Net Income		49,173	95,858	119,359	212,761
Less: Net (Loss) Income Attributable to Noncontrolling Interests		(51)	395	371	882
Net Income Attributable to RPM International Inc. Stockholders		$ 49,224	$ 95,463	$ 118,988	$ 211,879
Average Number of Shares of Common Stock Outstanding:
Basic		131,058	131,163	131,467	131,204
Diluted	[1]	131,667	135,592	133,278	135,663
Earnings per Share of Common Stock Attributable to RPM International Inc. Stockholders:
Basic		$ 0.37	$ 0.72	$ 0.90	$ 1.59
Diluted		0.37	0.70	0.89	1.56
Cash Dividends Declared per Share of Common Stock		$ 0.350	$ 0.320	$ 0.670	$ 0.620

[1] There were no shares of restricted stock identified as being anti-dilutive for the three or six months ended November 30, 2018. Restricted shares totaling 123,262 and 99,612 for the three and six months ended November 30, 2017, 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. In addition, stock appreciation rights (SARs) totaling 480,000 and 890,000 for the three and six months ended November 30, 2018 and 600,000 for the three and six months ended November 30, 2017, were excluded from the calculation of diluted earnings per share as their effect would have been anti-dilutive.