Note 7 - Related Party Transactions (Details Textual) - USD ($) |
3 Months Ended | ||
|---|---|---|---|
Jul. 31, 2026 |
Jul. 31, 2025 |
Apr. 30, 2026 |
|
| Ownership Percentage By Parent | 92.01% | ||
| AB and Co [Member] | |||
| Accounts Receivable, after Allowance for Credit Loss | $ 0 | $ 0 | |
| Reimbursement for Payments and Services [Member] | AB and Co [Member] | |||
| Related Party Transaction, Amounts of Transaction | 58,000 | $ 58,000 | |
| EAM Trust [Member] | |||
| Assets under Management, Carrying Amount | $ 3,400,000,000 | $ 5,010,000,000.00 | |
| Percentage of Assets Increased (Decreased) in Unconsolidated Entities | (32.20%) | ||
| Non Voting Profits Interest Percent | 50.00% | ||
| Accrued Investment Income Receivable | $ 3,827,000 | ||
| 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% | ||