Note 11 - Subsequent Events (Details Textual) - USD ($) | | | | 3 Months Ended | |
Aug. 01, 2022 | Jul. 28, 2022 | Jul. 14, 2022 | Jun. 30, 2022 | Jun. 30, 2021 | Aug. 02, 2022 |
Common Stock, Dividends, Per Share, Declared (in dollars per share) | | | | $ 0.30 | $ 0.30 | |
Restricted Stock [Member] | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares) | | | | 10,125 | 1,380 | |
Subsequent Event [Member] | Quarterly Dividend [Member] | | | | | | |
Common Stock, Dividends, Per Share, Declared (in dollars per share) | | $ 0.30 | | | | |
Dividends Payable | | | | | | $ 6,300,000 |
Chief Financial Officer [Member] | Subsequent Event [Member] | | | | | | |
Annual Salary | | | $ 375,000 | | | |
One-time Sign-on Bonus | | | $ 50,000 | | | |
Chief Financial Officer [Member] | Subsequent Event [Member] | 2016 Employee Equity Compensation Restricted Stock Plan [Member] | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Grant Released From Restriction Period (Year) | | | 3 years | | | |
Chief Financial Officer [Member] | Subsequent Event [Member] | Restricted Stock [Member] | The 2016 Employee Equity Compensation Restricted Stock Plan [Member] | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares) | | | 13,000 | | | |
Chief Financial Officer [Member] | Subsequent Event [Member] | Restricted Stock [Member] | 2016 Employee Equity Compensation Restricted Stock Plan [Member] | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares) | 13,000 | | | | | |
Chief Financial Officer [Member] | Subsequent Event [Member] | Performance Restricted Stock [Member] | The 2016 Employee Equity Compensation Restricted Stock Plan [Member] | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares) | | | 3,000 | | | |
Chief Financial Officer [Member] | Subsequent Event [Member] | Performance Restricted Stock [Member] | 2016 Employee Equity Compensation Restricted Stock Plan [Member] | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares) | 3,000 | | | | | |
Employees [Member] | Subsequent Event [Member] | Restricted Stock [Member] | 2016 Employee Equity Compensation Restricted Stock Plan [Member] | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares) | 7,000 | 39,215 | | | | |
Independent Directors [Member] | Subsequent Event [Member] | Restricted Stock [Member] | 2015 Outside Director Equity Compensation Restricted Stock Plan ("2015 Director Plan") [Member] | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares) | | 37,500 | | | | |