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, 2017	$ 1,438,700	$ 1,336	$ 954,491	$ (218,222)	$ (473,986)	$ 1,172,442	$ 1,436,061	$ 2,639
Beginning Balance (in shares) at May. 31, 2017		133,563,000
Net Income	116,903					116,416	116,416	487
Other comprehensive income (loss)	44,635				44,604		44,604	31
Dividends paid	(40,089)					(40,089)	(40,089)
Other noncontrolling interest activity	(65)							(65)
Stock compensation expense and other deferred compensation, shares granted less shares returned for taxes	2,119	$ (1)	7,465	(5,345)			2,119
Stock compensation expense and other deferred compensation, shares granted less shares returned for taxes (in shares)		(26,000)
Ending Balance at Aug. 31, 2017	1,562,203	$ 1,335	961,956	(223,567)	(429,382)	1,248,769	1,559,111	3,092
Ending Balance (in shares) at Aug. 31, 2017		133,537,000
Beginning Balance at May. 31, 2017	1,438,700	$ 1,336	954,491	(218,222)	(473,986)	1,172,442	1,436,061	2,639
Beginning Balance (in shares) at May. 31, 2017		133,563,000
Net Income	253,349
Other comprehensive income (loss)	68,241
Ending Balance at Feb. 28, 2018	1,636,022	$ 1,337	972,187	(233,288)	(405,734)	1,298,876	1,633,378	2,644
Ending Balance (in shares) at Feb. 28, 2018		133,730,000
Beginning Balance at Aug. 31, 2017	1,562,203	$ 1,335	961,956	(223,567)	(429,382)	1,248,769	1,559,111	3,092
Beginning Balance (in shares) at Aug. 31, 2017		133,537,000
Net Income	95,858					95,463	95,463	395
Other comprehensive income (loss)	(5,288)				(5,216)		(5,216)	(72)
Dividends paid	(42,790)					(42,790)	(42,790)
Other noncontrolling interest activity	(647)							(647)
Stock compensation expense and other deferred compensation, shares granted less shares returned for taxes	185	$ 2	6,963	(6,780)			185
Stock compensation expense and other deferred compensation, shares granted less shares returned for taxes (in shares)		129,000
Ending Balance at Nov. 30, 2017	1,609,521	$ 1,337	968,919	(230,347)	(434,598)	1,301,442	1,606,753	2,768
Ending Balance (in shares) at Nov. 30, 2017		133,666,000
Net Income	40,588					40,227	40,227	361
Other comprehensive income (loss)	28,895				28,864		28,864	31
Dividends paid	(42,793)					(42,793)	(42,793)
Other noncontrolling interest activity	(516)							(516)
Stock compensation expense and other deferred compensation, shares granted less shares returned for taxes	327		3,268	(2,941)			327
Stock compensation expense and other deferred compensation, shares granted less shares returned for taxes (in shares)		64,000
Ending Balance at Feb. 28, 2018	1,636,022	$ 1,337	972,187	(233,288)	(405,734)	1,298,876	1,633,378	2,644
Ending Balance (in shares) at Feb. 28, 2018		133,730,000
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	(2,834)					(2,834)	(2,834)
Net Income	70,186					69,764	69,764	422
Other comprehensive income (loss)	(34,236)				(33,978)		(33,978)	(258)
Dividends paid	(42,714)					(42,714)	(42,714)
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	(2,834)					(2,834)	(2,834)
Net Income	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	49,173					49,224	49,224	(51)
Other comprehensive income (loss)	(7,983)				(8,074)		(8,074)	91
Dividends 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	14,496					14,190	14,190	306
Other comprehensive income (loss)	22,919				23,443		23,443	(524)
Dividends 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