Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Nov. 30, 2016	Nov. 30, 2015	Nov. 30, 2016	Nov. 30, 2015
Income Statement [Abstract]
Net Sales		$ 1,190,770	$ 1,155,984	$ 2,442,833	$ 2,398,510
Cost of Sales		669,089	662,050	1,369,110	1,371,618
Gross Profit		521,681	493,934	1,073,723	1,026,892
Selling, General and Administrative Expenses		419,494	352,594	803,579	725,448
Goodwill and Other Intangible Asset Impairments		188,298		188,298
Interest Expense		22,905	22,478	45,683	44,938
Investment (Income), Net		(2,416)	(1,100)	(6,254)	(5,168)
Other Expense (Income), Net		257	(299)	799	(788)
(Loss) Income Before Income Taxes		(106,857)	120,261	41,618	262,462
(Benefit) Provision for Income Taxes		(36,601)	36,112	(1,520)	77,951
Net (Loss) Income		(70,256)	84,149	43,138	184,511
Less: Net Income Attributable to Noncontrolling Interests		670	716	1,295	1,263
Net (Loss) Income Attributable to RPM International Inc. Stockholders		$ (70,926)	$ 83,433	$ 41,843	$ 183,248
Average Number of Shares of Common Stock Outstanding:
Basic		130,695	129,398	130,647	129,723
Diluted	[1]	130,695	136,734	130,647	137,072
(Loss) Earnings per Share of Common Stock Attributable to RPM International Inc. Stockholders:
Basic		$ (0.54)	$ 0.63	$ 0.32	$ 1.39
Diluted		(0.54)	0.62	0.32	1.36
Cash Dividends Declared per Share of Common Stock		$ 0.300	$ 0.275	$ 0.575	$ 0.535

[1] 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.