Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Paid-In Capital	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Total RPM International Inc. Equity	Noncontrolling Interests
Beginning Balance at May. 31, 2019	$ 1,408,605	$ 1,310	$ 994,508	$ (437,290)	$ (577,628)	$ 1,425,052	$ 1,405,952	$ 2,653
Beginning Balance (in shares) at May. 31, 2019		130,995,000
Net income	106,496					106,188	106,188	308
Other comprehensive income (loss)	(23,656)				(23,625)		(23,625)	(31)
Dividends declared and paid	(45,323)					(45,323)	(45,323)
Other noncontrolling interest activity	(297)							(297)
Share repurchases under repurchase program	(100,000)	$ (16)	16	(100,000)			(100,000)
Share repurchases under repurchase program (in shares)		(1,656,000)
Stock compensation expense and other deferred compensation, shares granted less shares returned for taxes	200	$ 3	6,557	(6,360)			200
Stock compensation expense and other deferred compensation, shares granted less shares returned for taxes (in shares)		330,000
Ending Balance at Aug. 31, 2019	1,346,025	$ 1,297	1,001,081	(543,650)	(601,253)	1,485,917	1,343,392	2,633
Ending Balance (in shares) at Aug. 31, 2019		129,669,000
Beginning Balance at May. 31, 2019	1,408,605	$ 1,310	994,508	(437,290)	(577,628)	1,425,052	1,405,952	2,653
Beginning Balance (in shares) at May. 31, 2019		130,995,000
Net income	195,907
Other comprehensive income (loss)	(14,384)
Share repurchases under repurchase program	$ (100,000)
Share repurchases under repurchase program (in shares)	(1,655,616)
Ending Balance at Feb. 29, 2020	$ 1,353,349	$ 1,299	1,013,561	(553,663)	(592,024)	1,481,339	1,350,512	2,837
Ending Balance (in shares) at Feb. 29, 2020		129,879,000
Beginning Balance at Aug. 31, 2019	1,346,025	$ 1,297	1,001,081	(543,650)	(601,253)	1,485,917	1,343,392	2,633
Beginning Balance (in shares) at Aug. 31, 2019		129,669,000
Net income	77,322					77,030	77,030	292
Other comprehensive income (loss)	24,597				24,546		24,546	51
Dividends declared and paid	(46,717)					(46,717)	(46,717)
Other noncontrolling interest activity	(368)							(368)
Stock compensation expense and other deferred compensation, shares granted less shares returned for taxes	2,441	$ 1	6,473	(4,033)			2,441
Stock compensation expense and other deferred compensation, shares granted less shares returned for taxes (in shares)		97,000
Ending Balance at Nov. 30, 2019	1,403,300	$ 1,298	1,007,554	(547,683)	(576,707)	1,516,230	1,400,692	2,608
Ending Balance (in shares) at Nov. 30, 2019		129,766,000
Net income	12,090					11,853	11,853	237
Other comprehensive income (loss)	(15,325)				(15,317)		(15,317)	(8)
Dividends declared and paid	$ (46,744)					(46,744)	(46,744)
Share repurchases under repurchase program (in shares)	0
Stock compensation expense and other deferred compensation, shares granted less shares returned for taxes	$ 28	$ 1	6,007	(5,980)			28
Stock compensation expense and other deferred compensation, shares granted less shares returned for taxes (in shares)		113,000
Ending Balance at Feb. 29, 2020	1,353,349	$ 1,299	1,013,561	(553,663)	(592,024)	1,481,339	1,350,512	2,837
Ending Balance (in shares) at Feb. 29, 2020		129,879,000
Beginning Balance at May. 31, 2020	1,264,663	$ 1,295	1,014,428	(580,117)	(717,497)	1,544,336	1,262,445	2,218
Beginning Balance (in shares) at May. 31, 2020		129,511,000
Net income	180,785					180,595	180,595	190
Other comprehensive income (loss)	49,904				49,835		49,835	69
Dividends declared and paid	(46,622)					(46,622)	(46,622)
Stock compensation expense and other deferred compensation, shares granted less shares returned for taxes	3,341	$ 5	10,451	(7,115)			3,341
Stock compensation expense and other deferred compensation, shares granted less shares returned for taxes (in shares)		464,000
Ending Balance at Aug. 31, 2020	1,452,071	$ 1,300	1,024,879	(587,232)	(667,662)	1,678,309	1,449,594	2,477
Ending Balance (in shares) at Aug. 31, 2020		129,975,000
Beginning Balance at May. 31, 2020	1,264,663	$ 1,295	1,014,428	(580,117)	(717,497)	1,544,336	1,262,445	2,218
Beginning Balance (in shares) at May. 31, 2020		129,511,000
Net income	347,136
Other comprehensive income (loss)	94,673
Share repurchases under repurchase program	$ (24,600)
Share repurchases under repurchase program (in shares)	(290,174)
Ending Balance at Feb. 28, 2021	$ 1,549,670	$ 1,298	1,045,585	(621,836)	(622,937)	1,745,375	1,547,485	2,185
Ending Balance (in shares) at Feb. 28, 2021		129,815,000
Beginning Balance at Aug. 31, 2020	1,452,071	$ 1,300	1,024,879	(587,232)	(667,662)	1,678,309	1,449,594	2,477
Beginning Balance (in shares) at Aug. 31, 2020		129,975,000
Net income	127,884					127,659	127,659	225
Other comprehensive income (loss)	17,843				17,843		17,843
Dividends declared and paid	(49,397)					(49,397)	(49,397)
Stock compensation expense and other deferred compensation, shares granted less shares returned for taxes	2,042	$ 1	10,660	(8,619)			2,042
Stock compensation expense and other deferred compensation, shares granted less shares returned for taxes (in shares)		131,000
Ending Balance at Nov. 30, 2020	1,550,443	$ 1,301	1,035,539	(595,851)	(649,819)	1,756,571	1,547,741	2,702
Ending Balance (in shares) at Nov. 30, 2020		130,106,000
Net income	38,466					38,242	38,242	224
Other comprehensive income (loss)	26,926				26,882		26,882	44
Dividends declared and paid	(49,438)					(49,438)	(49,438)
Other noncontrolling interest activity	(785)							(785)
Share repurchases under repurchase program	$ (24,628)	$ (3)	3	(24,628)			(24,628)
Share repurchases under repurchase program (in shares)	(290,174)	(290,000)
Stock compensation expense and other deferred compensation, shares granted less shares returned for taxes	$ 8,686		10,043	(1,357)			8,686
Stock compensation expense and other deferred compensation, shares granted less shares returned for taxes (in shares)		(1,000)
Ending Balance at Feb. 28, 2021	$ 1,549,670	$ 1,298	$ 1,045,585	$ (621,836)	$ (622,937)	$ 1,745,375	$ 1,547,485	$ 2,185
Ending Balance (in shares) at Feb. 28, 2021		129,815,000