Note 11 - Shareholders' Equity (Details Textual) - USD ($)	3 Months Ended	12 Months Ended		163 Months Ended
	Sep. 30, 2026	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Mar. 31, 2026	Sep. 14, 2024	Jun. 30, 2024	Feb. 25, 2022	Feb. 24, 2022
Payments of Ordinary Dividends, Common Stock		$ 1,141,000	$ 1,208,000
Common Stock, Dividends, Per Share, Cash Paid (in dollars per share)		$ 0.0075	$ 0.0075
Payments for Repurchase of Common Stock		$ 1,972,000	$ 1,969,000
Excise Tax Liability Accrued on Stock Repurchases		$ 18,000	$ 19,000
Plan 1989 [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares)		1,600,000		1,600,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year)		10 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)		0	125,100
Plan 1989 [Member] | Share-Based Payment Arrangement, Tranche One [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage		20.00%
Plan 1997 [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares)		400,000		400,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year)		10 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)		0	0
Share Repurchase Plan Renewal December2012 December2020 [Member]
Stock Repurchase Program, Authorized Amount		$ 5,000,000	$ 5,000,000	$ 5,000,000	$ 5,000,000	$ 5,000,000	$ 6,500,000	$ 5,000,000	$ 2,750,000
Share Repurchase Program, Remaining Authorized, Amount		$ 4,100,000		$ 4,100,000
O 2026 M 7-9, Dividends [Member] | Forecast [Member]
Common Stock, Dividends, Per Share, Cash Paid (in dollars per share)	$ 0.0075
Conversion of Common Stock From Class C to Class A [Member]
Conversion of Stock, Shares Converted (in shares)		0	0
Common Class B [Member]
Preferred Stock, Shares Issued (in shares)		0	0	0
Common Class A [Member]
Payments of Ordinary Dividends, Common Stock		$ 955,000	$ 1,000,000
Treasury Stock, Shares, Acquired (in shares)		733,848	801,043	3,523,768
Payments for Repurchase of Common Stock		$ 2,000,000	$ 2,000,000	$ 9,500,000
Common Stock Award, Number of Shares Granted (in shares)		0	0
Common Class C [Member]
Payments of Ordinary Dividends, Common Stock		$ 186,000	$ 186,000