Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Nov. 30, 2021	Nov. 30, 2020	Nov. 30, 2021	Nov. 30, 2020
Statement of Comprehensive Income [Abstract]
Net Income	$ 125,116	$ 127,884	$ 259,911	$ 308,670
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments (net of tax of $1,521; $81; $3,858 and $2,944, respectively)	(46,866)	12,495	(85,846)	77,162
Pension and other postretirement benefit liability adjustments (net of tax of $1,213; $1,722; $2,679 and $2,508, respectively)	3,587	5,644	8,029	8,904
Unrealized gain (loss) on securities and other (net of tax of $90; $240; $235 and $322, respectively)	(177)	80	97	170
Unrealized gain (loss) on derivatives (net of tax of $3,142; $119, $5,713 and $5,662, respectively)	10,190	(376)	18,800	(18,489)
Total other comprehensive income (loss)	(33,266)	17,843	(58,920)	67,747
Total Comprehensive Income	91,850	145,727	200,991	376,417
Less: Comprehensive Income Attributable to Noncontrolling Interests	212	225	395	484
Comprehensive Income Attributable to RPM International Inc. Stockholders	$ 91,638	$ 145,502	$ 200,596	$ 375,933