Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Feb. 29, 2016	Feb. 28, 2015	Feb. 29, 2016	Feb. 28, 2015
Income Statement [Abstract]
Net Sales		$ 988,555	$ 946,367	$ 3,387,065	$ 3,221,391
Cost of Sales		575,593	566,629	1,947,211	1,879,317
Gross Profit		412,962	379,738	1,439,854	1,342,074
Selling, General and Administrative Expenses		370,913	346,171	1,096,361	1,027,585
Interest Expense		23,140	21,493	68,078	60,312
Investment (Income), Net		(2,909)	(7,693)	(8,077)	(16,554)
Other (Income), Net		(88)	(660)	(876)	(3,524)
Income (Expense) Before Income Taxes	[1]	21,906	20,427	284,368	274,255
Provision for Income Taxes		2,613	99,379	80,564	174,512
Net Income (Loss)		19,293	(78,952)	203,804	99,743
Less: Net Income (Loss) Attributable to Noncontrolling Interests		711	(21,604)	1,974	(11,754)
Net Income (Loss) Attributable to RPM International Inc. Stockholders		$ 18,582	$ (57,348)	$ 201,830	$ 111,497
Average Number of Shares of Common Stock Outstanding:
Basic		129,068	129,795	129,506	130,039
Diluted	[2],[3]	129,068	129,795	136,848	134,995
Earnings (Loss) per Share of Common Stock Attributable to RPM International Inc. Stockholders:
Basic		$ 0.14	$ (0.44)	$ 1.53	$ 0.84
Diluted		0.14	(0.44)	1.50	0.84
Cash Dividends Declared per Share of Common Stock		$ 0.275	$ 0.260	$ 0.810	$ 0.760

[1] The presentation includes a reconciliation of Income (Loss) Before Income Taxes, a measure defined by Generally Accepted Accounting Principles (GAAP) in the United States, to EBIT.

[2] For the nine month period ended February 28, 2015, approximately 3.0 million shares of stock granted under stock-based compensation plans were excluded from the calculation of diluted EPS, as the effect would have been anti-dilutive.

[3] For the three months ended February 28, 2015, basic weighted-average shares outstanding and basic net income available to common shareholders under the treasury method are used in calculating basic and diluted earnings per share as a result of the reported loss for the period. For the three month period ended February 29, 2016, basic weighted-average shares outstanding and basic net income available to common shareholders are used in calculating diluted earnings per share under the two-class method, as that method resulted in the most dilutive earnings per share. For the nine month period ended February 29, 2016, basic and diluted earnings per share are calculated under the two-class method and the treasury method, respectively, as those methods resulted in the most dilutive earnings per share.