Consolidated Statements of Income (USD $) In Thousands, except Per Share data	12 Months Ended
May 31, 2011	May 31, 2010	May 31, 2009
CONSOLIDATED STATEMENTS OF INCOME [ABSTRACT]
Net Sales	$ 3,381,841	$ 3,412,716	$ 3,368,167
Cost of Sales	(1,980,974)	(1,977,341)	(2,015,078)
Gross Profit	1,400,867	1,435,375	1,353,089
Selling, General and Administrative Expenses	(1,056,069)	(1,107,278)	(1,096,505)
Goodwill and Other Intangible Asset Impairments			(15,462)
Net loss upon deconsolidation of SPHC		(7,946)
Interest Expense	(65,427)	(59,273)	(54,460)
Investment Expense (Income), Net	15,682	7,576	(5,794)
Income Before Income Taxes	295,053	268,454	180,868
Provision for Income Taxes	(91,885)	(87,327)	(61,252)
Net Income	203,168	181,127	119,616
Less: Net Income Attributable to Noncontrolling Interests	14,110	1,090	0
Net Income Attributable to RPM International Inc. Stockholders	$ 189,058	$ 180,037	$ 119,616
Average Number of Shares of Common Stock Outstanding:
Basic	127,403	127,047	126,373
Diluted	128,066	127,731	127,689
Earnings Per Share of Common Stock Attributable to RPM International Inc. Stockholders:
Basic Earnings Per Share	$ 1.46	$ 1.40	$ 0.93
Diluted Earnings Per Share	$ 1.45	$ 1.39	$ 0.93
Cash Dividends Declared per Share of Common Stock	$ 0.835	$ 0.815	$ 0.790

Total loss recognized during the period from the impairment of goodwill plus the loss recognized in the period resulting from the impairment of the carrying amount of intangible assets, other than goodwill.

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Aggregate dividends declared during the period for each share of common stock outstanding.

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Total costs related to goods produced and sold during the reporting period.

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This element represents the gain or loss recognized by the parent and included in its attributable portion of net income for the period due to deconsolidation of a subsidiary by other than a nonreciprocal transfer to owners, such as a spin-off. The gain or loss recognized and included in the net income attributable to the parent for the period is generally computed as the difference between: (a) the aggregate of: (1) the fair value of any consideration received; (2) the fair value of any retained noncontrolling investment in the former subsidiary at the date the subsidiary was deconsolidated; and (3) the carrying amount of any noncontrolling interest in the former subsidiary (including any accumulated other comprehensive income attributable to the noncontrolling interest) at the date the subsidiary was deconsolidated and (b) the carrying amount of the former subsidiary's assets and liabilities.

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The amount of net income or loss for the period per each share of common stock outstanding during the reporting period.

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The amount of net income or loss for the period per each share of common stock and dilutive common stock equivalents outstanding during the reporting period.

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Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity.

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Sum of operating profit and nonoperating income (expense) before income (loss) from equity method investments, income taxes, extraordinary items, cumulative effects of changes in accounting principles, and noncontrolling interest.

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The sum of the current income tax expense (benefit) and the deferred income tax expense (benefit) pertaining to continuing operations.

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The cost of borrowed funds accounted for as interest that was charged against earnings during the period.

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This item represents investment income derived from investments in debt and equity securities consisting of interest income earned from investments in debt securities and on cash and cash equivalents, dividend income from investments in equity securities, and income or expense derived from the amortization of investment related discounts or premiums, respectively, net of related investment expenses. This item does not include realized or unrealized gains or losses on the sale or holding of investments in debt and equity securities required to be included in earnings for the period or for other than temporary losses related to investments in debt and equity securities which are included in realized losses in the period recognized, and does not include investment income from real or personal property, such as rental income.

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The portion of consolidated profit or loss for the period, net of income taxes, which is attributable to the parent. If the entity does not present consolidated financial statements, the amount of profit or loss for the period, net of income taxes.

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The portion of net income (loss) attributable to the noncontrolling interest (if any) deducted in order to derive the portion attributable to the parent.

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The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

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Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

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The aggregate total costs related to selling a firm's product and services, as well as all other general and administrative expenses. Direct selling expenses (for example, credit, warranty, and advertising) are expenses that can be directly linked to the sale of specific products. Indirect selling expenses are expenses that cannot be directly linked to the sale of specific products, for example telephone expenses, Internet, and postal charges. General and administrative expenses include salaries of non-sales personnel, rent, utilities, communication, etc.

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The average number of shares issued and outstanding that are used in calculating diluted EPS, determined based on the timing of issuance of shares in the period.

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This element represents the weighted average total number of shares issued throughout the period including the first (beginning balance outstanding) and last (ending balance outstanding) day of the period before considering any reductions (for instance, shares held in treasury) to arrive at the weighted average number of shares outstanding. Weighted average relates to the portion of time within a reporting period that common shares have been issued and outstanding to the total time in that period. Such concept is used in determining the weighted average number of shares outstanding for purposes of calculating earnings per share (basic).

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