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, 2018	$ 1,633,538	$ 1,336	$ 982,067	$ (236,318)	$ (459,048)	$ 1,342,736	$ 1,630,773	$ 2,765
Beginning Balance (in shares) at May. 31, 2018		133,647,000
Cumulative-effect adjustment upon adoption of ASU 2014-09 at May. 31, 2018	(2,833)					(2,833)	(2,833)
Net income (loss)	70,186					69,764	69,764	422
Other comprehensive income (loss)	(34,236)				(33,978)		(33,978)	(258)
Dividends declared and paid	(42,715)					(42,715)	(42,715)
Other noncontrolling interest activity	3							3
Share repurchases under repurchase program	(6,994)	$ (1)	1	(6,994)			(6,994)
Share repurchases under repurchase program (in shares)		(103,000)
Stock compensation expense and other deferred compensation, shares granted less shares returned for taxes	(3,570)	$ (1)	10,018	(13,587)			(3,570)
Stock compensation expense and other deferred compensation, shares granted less shares returned for taxes (in shares)		(136,000)
Ending Balance at Aug. 31, 2018	1,613,379	$ 1,334	992,086	(256,899)	(493,026)	1,366,952	1,610,447	2,932
Ending Balance (in shares) at Aug. 31, 2018		133,408,000
Beginning Balance at May. 31, 2018	1,633,538	$ 1,336	982,067	(236,318)	(459,048)	1,342,736	1,630,773	2,765
Beginning Balance (in shares) at May. 31, 2018		133,647,000
Cumulative-effect adjustment upon adoption of ASU 2014-09 at May. 31, 2018	(2,833)					(2,833)	(2,833)
Net income (loss)	133,855
Other comprehensive income (loss)	(19,299)
Share repurchases under repurchase program	$ (173,200)
Share repurchases under repurchase program (in shares)	(2,819,045)
Ending Balance at Feb. 28, 2019	$ 1,442,267	$ 1,315	984,358	(406,367)	(477,657)	1,337,545	1,439,194	3,073
Ending Balance (in shares) at Feb. 28, 2019		131,544,000
Beginning Balance at Aug. 31, 2018	1,613,379	$ 1,334	992,086	(256,899)	(493,026)	1,366,952	1,610,447	2,932
Beginning Balance (in shares) at Aug. 31, 2018		133,408,000
Net income (loss)	49,173					49,224	49,224	(51)
Other comprehensive income (loss)	(7,983)				(8,074)		(8,074)	91
Dividends declared and paid	(46,481)					(46,481)	(46,481)
Other noncontrolling interest activity	567							567
Share repurchases under repurchase program	(74,998)	$ (11)	11	(74,998)			(74,998)
Share repurchases under repurchase program (in shares)		(1,145,000)
Stock compensation expense and other deferred compensation, shares granted less shares returned for taxes	5,197	$ 2	7,277	(2,082)			5,197
Stock compensation expense and other deferred compensation, shares granted less shares returned for taxes (in shares)		274,000
Convertible bond redemption	(2,808)	$ 6	(23,029)	20,215			(2,808)
Convertible bond redemption (in shares)		599,000
Ending Balance at Nov. 30, 2018	1,536,046	$ 1,331	976,345	(313,764)	(501,100)	1,369,695	1,532,507	3,539
Ending Balance (in shares) at Nov. 30, 2018		133,136,000
Net income (loss)	14,496					14,190	14,190	306
Other comprehensive income (loss)	22,919				23,443		23,443	(524)
Dividends declared and paid	(46,340)					(46,340)	(46,340)
Other noncontrolling interest activity	(248)							(248)
Share repurchases under repurchase program	$ (91,230)	$ (16)	16	(91,230)			(91,230)
Share repurchases under repurchase program (in shares)	(1,570,647)	(1,571,000)
Stock compensation expense and other deferred compensation, shares granted less shares returned for taxes	$ 6,624		7,997	(1,373)			6,624
Stock compensation expense and other deferred compensation, shares granted less shares returned for taxes (in shares)		(21,000)
Ending Balance at Feb. 28, 2019	1,442,267	$ 1,315	984,358	(406,367)	(477,657)	1,337,545	1,439,194	3,073
Ending Balance (in shares) at Feb. 28, 2019		131,544,000
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 (loss)	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 (loss)	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 (loss)	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 (loss)	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