Components of Total Equity and Comprehensive Income (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended			9 Months Ended
	Feb. 28, 2013		Feb. 29, 2012	Feb. 28, 2013		Feb. 29, 2012
Stockholders Equity Note [Line Items]
Total equity, beginning of period	$ 1,374,550	[1]	$ 1,388,027	$ 1,313,983		$ 1,387,368
Net income (loss)	(24,200)	[1]	7,924	41,762		145,183
Other Comprehensive Income:
Foreign Currency Translation Adjustments	(19,938)	[1]	22,257	17,256		(51,160)
Pension and other postretirement benefit liability adjustments, net of tax	5,278	[1]	871	9,862		6,270
Unrealized gain (loss) on securities, net of tax	(712)	[1]	2,474	1,012		(8,498)
Unrealized (loss) on derivatives, net of tax	328	[1]	(793)	(229)		(4,665)
Total Other Comprehensive Income, net of tax	(15,044)	[1]	24,809	27,901		(58,053)
Total Comprehensive Income	(39,244)	[1]	32,733	69,663		87,130
Dividends paid	(29,778)	[1]	(28,251)	(87,832)		(83,871)
Other noncontrolling interest activity	(152)	[1]	1,118	157		(875)
Shares repurchased	(1,235)	[1]		(2,329)		(3,008)
Stock option exercises, net	1,384	[1]	2,970	3,749		6,151
Stock based compensation expense	583	[1]	3,182	1,794		9,874
Restricted awards, net	3,637	[1]	(575)	10,560		(3,565)
Total Equity, end of period	1,309,745	[1]	1,399,204	1,309,745	[1]	1,399,204
Total RPM International Inc. Equity
Stockholders Equity Note [Line Items]
Total equity, beginning of period	1,224,960	[1]	1,255,094	1,183,656		1,263,164
Net income (loss)	(24,364)	[1]	6,625	33,225		133,367
Other Comprehensive Income:
Foreign Currency Translation Adjustments	(19,401)	[1]	24,083	5,604		(45,821)
Pension and other postretirement benefit liability adjustments, net of tax	4,736	[1]	983	9,512		5,823
Unrealized gain (loss) on securities, net of tax	(1,626)	[1]	3,592	1,064		(9,374)
Unrealized (loss) on derivatives, net of tax	238	[1]	(623)	(178)		(3,667)
Total Other Comprehensive Income, net of tax	(16,053)	[1]	28,035	16,002		(53,039)
Total Comprehensive Income	(40,417)	[1]	34,660	49,227		80,328
Dividends paid	(29,778)	[1]	(28,251)	(87,832)		(83,871)
Other noncontrolling interest activity	(152)	[1]	1,118	157		(875)
Shares repurchased	(1,235)	[1]		(2,329)		(3,008)
Stock option exercises, net	1,384	[1]	2,970	3,749		6,151
Stock based compensation expense	583	[1]	3,182	1,794		9,874
Restricted awards, net	3,637	[1]	(575)	10,560		(3,565)
Total Equity, end of period	1,158,982	[1]	1,268,198	1,158,982	[1]	1,268,198
Noncontrolling Interest
Stockholders Equity Note [Line Items]
Total equity, beginning of period	149,590		132,933	130,327		124,204
Net income (loss)	164		1,299	8,537		11,816
Other Comprehensive Income:
Foreign Currency Translation Adjustments	(537)		(1,826)	11,652		(5,339)
Pension and other postretirement benefit liability adjustments, net of tax	542		(112)	350		447
Unrealized gain (loss) on securities, net of tax	914		(1,118)	(52)		876
Unrealized (loss) on derivatives, net of tax	90		(170)	(51)		(998)
Total Other Comprehensive Income, net of tax	1,009		(3,226)	11,899		(5,014)
Total Comprehensive Income	1,173		(1,927)	20,436		6,802
Total Equity, end of period	$ 150,763		$ 131,006	$ 150,763		$ 131,006

[1] Restated