Note 1 - Organization and Summary of Significant Accounting Policies (Details Textual) - USD ($)	12 Months Ended
Apr. 30, 2016	Apr. 30, 2015
EAM Trust [Member] \| Minimum [Member]
Non Voting Revenues Interest Percent	41.00%
Percentage of Non Voting Profits Interests Due from Ex Subsidiary Payable to Parent under Agreement	90.00%
EAM Trust [Member] \| Maximum [Member]
Non Voting Revenues Interest Percent	55.00%
EAM Trust [Member]
Non Voting Profits Interest Percent	50.00%
Cash and Cash Equivalents, Fair Value Disclosure	$ 12,037,000	$ 5,272,000

Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash
-URI http://asc.fasb.org/extlink&oid=6506951

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash Equivalents
-URI http://asc.fasb.org/extlink&oid=6507016

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