Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Aug. 31, 2020	Aug. 31, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net Income	$ 180,785	$ 106,496
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments (net of tax of $2,862 and $0, respectively)	64,667	(28,434)
Pension and other postretirement benefit liability adjustments (net of tax of $786 and $1,104, respectively)	3,260	3,623
Unrealized gain on securities and other (net of tax benefit of $82 and tax $1, respectively)	89	371
Unrealized gain (loss) on derivatives (net of tax of $5,542 and $579, respectively)	(18,112)	784
Total other comprehensive income (loss)	49,904	(23,656)
Total Comprehensive Income	230,689	82,840
Less: Comprehensive Income Attributable to Noncontrolling Interests	259	277
Comprehensive Income Attributable to RPM International Inc. Stockholders	$ 230,430	$ 82,563