Document and Entity Information - shares	9 Months Ended
	Feb. 28, 2017	Mar. 31, 2017
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Feb. 28, 2017
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	Q3
Trading Symbol	WOR
Entity Registrant Name	WORTHINGTON INDUSTRIES INC
Entity Central Index Key	0000108516
Current Fiscal Year End Date	--05-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		63,680,574