REVENUES - Building sales and other revenues (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Jan. 31, 2023	Jan. 31, 2022	Jan. 31, 2023	Jan. 31, 2022
Building sales and other revenues
Sale of buildings				$ 6,750
Oil and gas royalties	$ 34	$ 48	$ 140	223
Miscellaneous other revenues	77	88	462	290
Total	$ 111	$ 136	$ 602	$ 7,263

Ancillary revenue earned during the period from the consideration paid to the entity for the use of its rights and property by another party. Examples include licensing the use of copyrighted materials and leasing the extraction of natural resources.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.7)
-URI https://asc.fasb.org/extlink&oid=126953954&loc=SL114868664-224227

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