SCHEDULE II - Valuation and Qualifying Accounts (Parenthetical ) (Detail) $ in Thousands	12 Months Ended
May 31, 2018 USD ($)
Worthington Aritas
Valuation and Qualifying Accounts Disclosure [Line Items]
Assets held for sale	$ 1,215

The increase (decrease) during the period in book value of long-lived assets that the reporting entity plans to sell within one year (or one business cycle).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

Name:	us-gaap_IncreaseDecreaseInAssetsHeldForSale
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration