Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Aug. 31, 2021	Aug. 31, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net Income	$ 134,795	$ 180,785
Other comprehensive income, net of tax:
Foreign currency translation adjustments (net of tax of $2,337 and $2,862, respectively)	(38,980)	64,667
Pension and other postretirement benefit liability adjustments (net of tax of $1,466 and $786, respectively)	4,442	3,260
Unrealized gain on securities and other (net of tax of $145 and $82, respectively)	274	89
Unrealized gain (loss) on derivatives (net of tax of $2,571 and $5,542, respectively)	8,610	(18,112)
Total other comprehensive income (loss)	(25,654)	49,904
Total Comprehensive Income	109,141	230,689
Less: Comprehensive Income Attributable to Noncontrolling Interests	183	259
Comprehensive Income Attributable to RPM International Inc. Stockholders	$ 108,958	$ 230,430