Note 11 - Finance Lease Right-of-use - Finance Lease Right-of-use Assets (Details) - USD ($) $ in Thousands	Jan. 31, 2020	Apr. 30, 2019
Right-of-use assets	$ 44,349	$ 1,699
Less accumulated depreciation	2,130
Total	$ 42,219

Amount of lessee's right to use underlying asset under finance lease.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977

Name:	us-gaap_FinanceLeaseRightOfUseAsset
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant