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	70,186					69,764	69,764	422
Other comprehensive (loss)	(34,236)				(33,978)		(33,978)	(258)
Dividends 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)	(103,446)	(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, 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 (loss)	(23,656)				(23,625)		(23,625)	(31)
Dividends 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)	(1,655,616)	(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