Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Feb. 28, 2018	Feb. 28, 2017	Feb. 28, 2018	Feb. 28, 2017
Income Statement [Abstract]
Net Sales		$ 1,102,677	$ 1,022,496	$ 3,763,487	$ 3,465,329
Cost of Sales		663,184	593,923	2,200,971	1,963,033
Gross Profit		439,493	428,573	1,562,516	1,502,296
Selling, General and Administrative Expenses		382,972	386,032	1,196,980	1,189,611
Goodwill and Other Intangible Asset Impairments			4,900		193,198
Interest Expense		27,459	23,769	80,628	69,452
Investment (Income), Net		(5,471)	(3,627)	(13,663)	(9,881)
Other (Income) Expense, Net		(165)	502	(592)	1,301
Income Before Income Taxes		34,698	16,997	299,163	58,615
(Benefit) Provision for Income Taxes		(5,890)	4,313	45,814	2,793
Net Income		40,588	12,684	253,349	55,822
Less: Net Income Attributable to Noncontrolling Interests		361	756	1,243	2,051
Net Income Attributable to RPM International Inc. Stockholders		$ 40,227	$ 11,928	$ 252,106	$ 53,771
Average Number of Shares of Common Stock Outstanding:
Basic		131,178	130,677	131,195	130,657
Diluted	[1]	131,178	130,677	135,657	130,657
Earnings per Share of Common Stock Attributable to RPM International Inc. Stockholders:
Basic		$ 0.30	$ 0.09	$ 1.90	$ 0.41
Diluted		0.30	0.09	1.87	0.41
Cash Dividends Declared per Share of Common Stock		$ 0.320	$ 0.300	$ 0.940	$ 0.875

[1] Restricted shares totaling 48,212 for the three and nine months ended February 28, 2018 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, 2018 and 2017 were excluded from the calculation of diluted earnings per share as their effect would have been anti-dilutive.