Consolidated Statements of Stockholders' Equity (Parenthetical) - $ / shares	3 Months Ended	6 Months Ended
Aug. 31, 2019	Aug. 31, 2018	Nov. 30, 2019	Nov. 30, 2018
Statement Of Stockholders Equity [Abstract]
Dividends declared and paid per share	$ 0.35	$ 0.32	$ 0.36	$ 0.35

Common stock dividends declared and paid per share.

No definition available.

Name:	rpm_CommonStockDividendsDeclaredAndPaidPerShare
Namespace Prefix:	rpm_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration